Ebook Thermodynamic Analysis and Optimization of Geothermal Power Plants PDF Full Chapter PDF

Thermodynamic Analysis and
Optimization of Geothermal Power

Plants - eBook PDF
Visit to download the full and correct content document:
https://ebooksecure.com/download/thermodynamic-analysis-and-optimization-of-geot
hermal-power-plants-ebook-pdf/
Thermodynamic Analysis and Optimization
of Geothermal Power Plants
Thermodynamic Analysis
and Optimization of
Geothermal Power Plants
Edited by
Can Ozgur Colpan
Mehmet Akif Ezan
Onder Kizilkan
Elsevier
Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands
The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom
50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States
Copyright © 2021 Elsevier Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying, recording, or any information storage and retrieval system, without
permission in writing from the publisher. Details on how to seek permission, further information about the
Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance
Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions.
This book and the individual contributions contained in it are protected under copyright by the Publisher (other
than as may be noted herein).
Notices
Knowledge and best practice in this field are constantly changing. As new research and experience broaden our
understanding, changes in research methods, professional practices, or medical treatment may become
necessary.
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using
any information, methods, compounds, or experiments described herein. In using such information or methods
they should be mindful of their own safety and the safety of others, including parties for whom they have a
professional responsibility.
To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability
for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or
from any use or operation of any methods, products, instructions, or ideas contained in the material herein.
Library of Congress Cataloging-in-Publication Data

A catalog record for this book is available from the Library of Congress
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library
ISBN: 978-0-12-821037-6
For information on all Elsevier publications

visit our website at https://www.elsevier.com/books-and-journals
Publisher: Brian Romer

Acquisitions Editor: Graham Nisbet
Editorial Project Manager: Leticia M. Lima
Production Project Manager: Poulouse Joseph
Cover Designer: Miles Hitchen
Typeset by SPi Global, India

Contributors
Numbers in parenthesis indicate the pages on which the authors’ C. Ozgur Colpan (153) The Graduate School of Natural
contributions begin. and Applied Sciences; Faculty of Engineering,
Department of Mechanical Engineering, Dokuz Eylul
Sertaҫ Akar (17) National Renewable Energy Laboratory University, Buca, Izmir, Turkey
(NREL), Golden, CO, United States
Ibrahim Dincer (207, 225) Clean Energy Research
Olusola Charles Akinsipe (3) School of Engineering & Built Laboratory, Faculty of Engineering and Applied
Environment, Griffith University, Brisbane, QLD, Australia Science, University of Ontario Institute of Technology,
Panagiotis Alexopoulos (131) Laboratory of Soft Energy Oshawa, ON, Canada
Applications and Environmental Protection, Mechanical Anil Erdogan (153) The Graduate School of Natural and
Engineering Department, University of West Attica, Applied Sciences, Dokuz Eylul University, Buca, Izmir,
Athens, Greece Turkey
Sharjeel Ashraf Ansari (249) Department of Engineering Mehmet Akif Ezan (153) The Graduate School of Natural
Sciences, National University of Sciences and Tech- and Applied Sciences; Faculty of Engineering,
nology, Islamabad, Pakistan Department of Mechanical Engineering, Dokuz Eylul
Chad Augustine (17) National Renewable Energy Labo- University, Buca, Izmir, Turkey
ratory (NREL), Golden, CO, United States Muhammad Farooq (315) Department of Mechanical
Muhammad Aziz (97) Institute of Industrial Science, The Engineering, University of Engineering and Tech-
University of Tokyo, Tokyo, Japan nology, KSK Campus, Lahore, Pakistan
Young-Jin Baik (315) Thermal Energy Systems Labo- Milad Feili (167) Department of Mechanical Engineering,
ratory, Korea Institute of Energy Research, Daejeon, Faculty of Engineering, University of Mohaghegh Ard-
Republic of Korea abili, Ardabil, Iran
gul (113) Department of Mechanical Engi-
Yusuf Başo Hikari Fujii (83) Graduate School of Engineering and
neering, Engineering Faculty, Adıyaman University, Resource Science, Akita University, Akita, Japan
Adıyaman, Turkey Hadi Ghaebi (167) Department of Mechanical Engi-
Riccardo Basosi (53) Center for Colloid and Surface neering, Faculty of Engineering, University of Moha-
Science, University of Firenze, Sesto Fiorentino; R2ES ghegh Ardabili, Ardabil, Iran
Lab, Department of Biotechnology, Chemistry and Onur Vahip G€ uler (113) Department of Energy Systems
Pharmacy, University of Siena, Siena; National Research Engineering, Technology Faculty, Mugla Sıtkı Koçman
Council—Institute for the Chemistry of OrganoMetallic University, Mugla, Turkey
Compounds, Sesto Fiorentino, Italy
Muhammad Imran (315) School of Engineering and
Joseph Bonafin (43) Turboden S.p.A., Brescia, Italy Applied Science, Aston University, Birmingham, West
Arianna Bonzanini (43) Turboden S.p.A., Brescia, Italy Midlands, United Kingdom
urcan Çetin (263) Department of Information Systems
G€ Mohammad Ashar Jamal (185) Department of Engi-
Engineering, Technology Faculty, Mu
gla Sıtkı Koçman neering Sciences, National University of Sciences and
University, Mu
gla, Turkey Technology, Islamabad, Pakistan
George Charis (131) Laboratory of Soft Energy Applications Rao Hamza Jamil (185) Department of Engineering Sci-
and Environmental Protection, Mechanical Engineering ences, National University of Sciences and Technology,
Department, University of West Attica, Athens, Greece Islamabad, Pakistan
xi
xii Contributors
Firman Bagja Juangsa (97) Faculty of Mechanical and Farayi Musharavati (279) Department of Mechanical
Aerospace Engineering, Institut Teknologi Bandung, and Industrial Engineering, Qatar University, Doha,
Bandung, Indonesia Qatar
Khurram Kamal (249) Department of Engineering Sci- Greg F. Naterer (225) Clean Energy Research Laboratory,
ences, National University of Sciences and Technology, Faculty of Engineering and Applied Science, Uni-
Islamabad, Pakistan versity of Ontario Institute of Technology, Oshawa,
Prasad Kaparaju (3) Institute for Applied Sustainability ON; Faculty of Engineering and Applied Science,
Research (iiasur), Quito, Ecuador; School of Engi- Memorial University of Newfoundland, St. John’s,
neering & Built Environment, Griffith University, NL, Canada
Brisbane, QLD, Australia €
Osman Ozkaraca (263) Department of Information
Spyridon Karytsas (65) Geothermal Energy Department, Systems Engineering, Technology Faculty, Mu gla Sıtkı
Division of Renewable Energy Sources, Centre for Koçman University, Mugla, Turkey
Renewable Energy Sources and Saving (CRES), Murat Ozturk (207) Faculty of Technology, Department of
Pikermi; Department of Home Economics and Ecology, Mechatronics Engineering, Isparta University of
School of Environment, Geography and Applied Eco- Applied Science, Isparta, Turkey
nomics, Harokopio University (HUA), Kallithea, Mohammad Mustafa Pardesi (185) Department of Engi-
Greece neering Sciences, National University of Sciences and
Kosmas A. Kavadias (131) Laboratory of Soft Energy Technology, Islamabad, Pakistan
Applications and Environmental Protection, Mechanical Maria Laura Parisi (53) Center for Colloid and Surface
Engineering Department, University of West Attica, Science, University of Firenze, Sesto Fiorentino; R2ES
Athens, Greece Lab, Department of Biotechnology, Chemistry and
Ali Keçebaş (113, 263) Department of Energy Systems Pharmacy, University of Siena, Siena; National
Engineering, Technology Faculty, Mu
gla Sıtkı Koçman Research Council—Institute for the Chemistry of
University, Mugla, Turkey OrganoMetallic Compounds, Sesto Fiorentino, Italy
Shoaib Khanmohammadi (279) Department of Olympia Polyzou (65) Geothermal Energy Department,
Mechanical Engineering, Kermanshah University of Division of Renewable Energy Sources, Centre for
Technology, Kermanshah, Iran Renewable Energy Sources and Saving (CRES),
Onder Kizilkan (153, 279) Department of Mechanical Pikermi, Greece
Engineering, Faculty of Technology, Isparta University Tahir Abdul Hussain Ratlamwala (185, 249) Department
of Applied Sciences, Isparta, Turkey of Engineering Sciences, National University of Sci-
Parthiv Kurup (17) National Renewable Energy Labo- ences and Technology, Islamabad, Pakistan
ratory (NREL), Golden, CO, United States Zabdur Rehman (315) Department of Mechanical Engi-
Saeid Mohammadzadeh Bina (83) Graduate School of neering, Air University Islamabad, Aerospace and Avi-
Engineering and Resource Science, Akita University, ation Campus, Kamra, Pakistan
Akita, Japan Ron R. Roberts (225) Clean Energy Research Laboratory,
Diego Moya (3) Department of Chemical Engineering Faculty of Engineering and Applied Science, University
& Grantham Institute—Climate Change and the of Ontario Institute of Technology, Oshawa, ON,
Environment, Science and Solutions for a Changing Canada
Planet DTP, Imperial College London, London, Hadi Rostamzadeh (167) Energy and Environment
United Kingdom; Institute for Applied Sustainability Research Center, Niroo Research Institute (NRI),
Research (iiasur), Quito; Carrera de Ingenierı́a Tehran, Iran
Mecánica, Facultad de Ingenierı́a Civil y Mecánica,
Universidad Tecnica de Ambato, Ambato; Lalit Chandra Saikia (293) Department of Electrical Engi-
Coordinación de Investigación e Innovación, ABREC, neering, National Institute of Technology, Silchar,
Quito, Ecuador Assam, India
Hafiz Ali Muhammad (315) Thermal Energy Systems Muhammad Nouman Saleem (249) Department of Engi-
Laboratory, Korea Institute of Energy Research, neering Sciences, National University of Sciences and
Daejeon, Republic of Korea Technology, Islamabad, Pakistan
Contributors xiii
Muhammad Afzal Sheikh (249) Department of Engi- Washima Tasnin (293) School of Electrical Engineering,
neering Sciences, National University of Sciences and Vellore Institute of Technology, Vellore, Tamil Nadu,
Technology, Islamabad, Pakistan India
Farooq Sher (315) School of Mechanical, Aerospace and Lorenzo Tosti (53) Center for Colloid and Surface Science,
Automotive Engineering, Coventry University, Cov- University of Firenze, Sesto Fiorentino; R2ES Lab,
entry, United Kingdom Department of Biotechnology, Chemistry and
Uzair Aziz Suria (185) Department of Engineering Sci- Pharmacy, University of Siena, Siena, Italy
ences, National University of Sciences and Technology, Shunsuke Tsuya (83) Graduate School of Engineering and
Islamabad, Pakistan Resource Science, Akita University, Akita, Japan
Chapter 1
Various cycle configurations for

geothermal power plants
Diego Moyaa,b,c,d, Olusola Charles Akinsipee, and Prasad Kaparajub,e
a
Department of Chemical Engineering & Grantham Institute—Climate Change and the Environment, Science and Solutions for a Changing Planet DTP,
Imperial College London, London, United Kingdom, b Institute for Applied Sustainability Research (iiasur), Quito, Ecuador, c Carrera de Ingenierı´a
ecnica de Ambato, Ambato, Ecuador, d Coordinación de Investigación e Innovación,
Mecánica, Facultad de Ingenierı´a Civil y Mecánica, Universidad T
ABREC, Quito, Ecuador, e School of Engineering & Built Environment, Griffith University, Brisbane, QLD, Australia
1.1 Introduction reservoir [8]. Depending upon the location, temperature,

and depth of the geothermal reservoir, geothermal fluids
Globally, the transition from the present petroleum- consisting of mineral-coated hot water known as brine
dependent energy technology to green energy is fundamen- and steam (vapor-dominated fluids) are generally used
tally contingent on making a decision on result-driven [9]. The heat energy that is transported to the ground surface
renewable systems [1]. Mitigating climate issues as well is further processed for electricity generation and/or direct
as promoting sustainable development are unattainable uses [8]. Depending on the geothermal site features, thermal
without innovative systems and technology transfer. Fea- energy can be harvested from depths of 300 to 3000 m and
tures such as low greenhouse gas emissions, minimized beyond. At greater depths, thermofluids are naturally
environmental disruption, and the viability of technology occurring as the porous hot rock of the hydrothermal and
extraction have demonstrated geothermal energy as a sus- geopressured geothermal reservoirs [10]. Harvesting the
tainable energy resource [2] that could be harnessed and hot fluids is a contingent feature of these reservoirs, and
exploited regardless of climatic factors [3]. The Earth’s various control measures are factored to maximize the uti-
crust houses the renewable geothermal energy source [4], lization of this heat energy [11]. Finally, the electrical power
usually associated with tectonic activity and volcanic activ- generation is dependent upon the application of various geo-
ities [5]. Typically, geothermal energy is located as a heat thermal heat [12]. In this chapter, current geothermal power
source in hot rocks [6] as well as hydrothermal reservoirs plant systems and their significance in applying cutting-
in the Earth’s crust. edge geothermal configurations as well as undertaking
Geothermal energy is considered a sustainable clean research on hybrid configurations are presented.
renewable energy resource. The global installed geothermal
capacity is estimated to be 12.729 MW and that is projected
to grow by 68.46% in 2020. Among the geothermal power
plant configurations, single flash (41%) is the predominant 1.2 Geothermal power plant system
configuration followed by dry steam (23%), double flash The abundance of hydrothermal resources has influenced
(19%), and binary (14%). The triple flash (2%) and back the development of geothermal power plant arrangements
pressure (1%) plant configurations are less popular [7]. and systems [13]. Geothermal power plants can be classified
Factors such as the heat reinjection mechanism, geothermal as single-flash steam power plants, double-flash steam
applications, and geologic time scale are backstopping the power plants, dry steam power plants, binary (Organic
accelerated geothermal reservoir heat extraction in com- Rankine-Kalina Cycle) power plants, and advanced geo-
parison with the replacement of heat in the reservoirs. thermal energy systems. The advanced geothermal energy
However, methods for heat reinjection have been developed systems are further classified as hybrid single-double-flash
to ensure geothermal energy as a renewable energy systems, hybrid flash-binary systems, hybrid fossil-
resource. geothermal technologies, and hybrid other renewable heat
Geothermal fluids are generally used to capture heat source-geothermal systems [12]. Geothermal power plants
energy from the Earth’s crust and transport it to the surface are best grouped into steam and binary cycles for cycles
through production wells drilled into the geothermal for higher well enthalpies and lower enthalpies, respectively
Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00005-6

Copyright © 2021 Elsevier Inc. All rights reserved. 3
4 PART I Basics of geothermal power plants
[14]. This chapter will assess the thermodynamic aspects of thermal production wells. The identified constraint is the
the five geothermal power plant configurations. drop in vapor pressure due to the pipe frictional force asso-
ciated with harvesting mechanisms [16]. Empirical correla-
tions are investigated, considering their complication and
1.2.1 Single-flash steam power plants
reliability, by deploying factors such as the vapor mass flow
The single-flash steam power plant is the simplest geo- rate, the density, the pipe diameter, the length, and the com-
thermal power transformation arrangement. This configu- ponents of the pipe to forecast pressure loss. The variables
ration facilitates liquid-vapor production from the are significant compared to the investment cost of the power
geothermal production wells. Based on their large density plant and the energy conversion technology [16]. A turbine
disparity, these are separated into two dissimilar phases: generator produces electrical energy from vapor (around
steam and liquid with the support of a cylindrical cyclone 99.95% dry) after separation of the vapor and liquid [15].
pressure vessel [14]. The term “single” depicts a single The choice of a single-flash process is applicable when
flashing mechanism of the geofluid obtained by depres- the geothermal fluid temperature exceeds 260°C with the
suring the geothermal fluid pressure [15]. This can be attainment of a capacity factor between 95% and 100% [10].
achieved in a production well, a reservoir, or a cyclone inlet Fig. 1.1 shows the single-flash process of energy con-
to support the transition of pressurized liquid to liquid-steam version technology. Station 1 is where the single-flash
mixture production. A 30 MW single-flash geothermal steam power process commences while the geothermal fluid
power plant demands between 5 and 6 production wells accesses the production well through the source inlet tem-
and 2–3 reinjection wells appropriated along with the geo- perature. Between stations 1 and 2 (producing pipes), a
fluid resource [15]. Further, pipes are deployed for mixture pressure drop occurs, and this facilitates the boiling of the
accumulation and transportation from the various geofluid (a vapor-liquid mixture) before it is transported to
SV
CV
MR
EG
T G
5
BCV c2
3
SE/C 6
ST C CT
CS
CP c1
WV WV ST
S CWP
WH 7
2
IW 4
PW 1
PW Production well BCV Ball check valve SV Stop valve

S Silencer MR Moisture remover SE Steam jet ejectors
WV Well valves ST Steam tramp C Condenser
CS Cyclone separator CV Control valve CP Condensate pump
IW Injection well EG Electric grid CWP Condensed water pump
G Generator T Turbine WH Wellhead
FIG. 1.1 Single-flash geothermal power cycle [17].
Various cycle configurations for geothermal power plants Chapter 1 5
station 2. At station 5, it collects steam from the mixture principle, the two fundamental thermodynamic principles,
fluid after separation while the brine (mineral-laden hot are considered in the investigation of the process with the
water) is collected at station 3 before reinjecting at station 4. aid of the diagram. In a single-flash power plant, flashing
At station 5, the induced motion of the turbine generator occurs when the geothermal fluid under pressure initiates
supports the electrical energy at the entrance of the steam, the process close to the saturation curve at state 1
followed by the production of steam expansion along with (Fig. 1.2). The change in the potential or kinetic energy is
the turbine to station 6 at condenser pressure. An air cooler not considered, and the enthalpy (h) is designed as constant,
condenser may be used at station c1 to allow the cooling of h1 ¼ h2, as can be seen in Eq. (1.1) in Table 1.1. After the
air and exit at station c2 [15]. The significance of certain flashing process, the separation process occurs at state 2,
plant equipment in the operation of a single-flash steam geo- and is simulated at constant pressure. Further, the vapor
thermal power plant is greatly acknowledged. In this config- and liquid mixture is shown, ascertaining the mixture
uration, large amounts of freshwater are not needed for quality in this state. The dryness fraction (x2) drives this
cooling [18]. Nevertheless, cooling the tower, particularly quality, as shown by Eq. (1.2) in Table 1.1. The quantity
the dry regions without fresh water, is achieved by of vapor entering the turbine is represented by the steam
deploying cooling water obtained from condensed mass fraction. Eq. (1.3) in Table 1.1 shows the work per unit
steam [16]. mass (w1) generated by the turbine expansion process
Fig. 1.2 is a thermodynamic state (T-s) diagram ana- between states 4 and 5. The potential and kinetic energy
lyzing the single-flash steam conversion process. It should are not generally considered, and heat losses are neglected
be noted that mass conversion and the energy conversion when the thermal fluid enters and leaves the turbine.
Eq. (1.4) in Table 1.1 is the isentropic turbine efficiency,
which is denoted by t. This is considered the ratio of the
actual work to that of the isentropic work, which is the ideal
process from states 4 to 5. Eq. (1.5) indicates the turbine
gross mechanical power (W_ t ). The electrical power output
of the generator (Eq. 1.6) is given as the turbine’s
mechanical power times the efficiency of the generator
(g). Lastly, at states 5 and 6, the condensation and cooling
processes occur, and Eq. (1.7) gives the cooling water flow
rate [4].
For the purpose of analyzing the whole plant efficiency,
the second law of thermodynamics is investigated [16]. This
allows its examination in contrast to the actual power output
toward the finish of the single-flash process and to the
utmost theoretical power that is generated by the geothermal
FIG. 1.2 Temperature-entropy (T-s) diagram of a single-flash cycle [4]. fluid [15]. Exergy is the energy feasible to be used and the
capacity to produce work from energy [16]. Eq. (1.8) pre-
sented in Table 1.2 defines the specific exergy (ex) of the
TABLE 1.1 Equations used for thermodynamic state analysis [15].

State Main characteristics Equation Equation number
Flashing process Constant enthalpy h1 ¼ h2 (1.1)
Separation process Constant pressure x2 ¼ hh24 h3
h3
(1.2)
Liquid plus vapor mixture
Turbine expansion process Constant entropy w1 ¼ h4 h5 (1.3)
t ¼ hh44h
h5
5s
(1.4)
W_ t ¼ m_ s wt (1.5)
W_ e ¼ g W_ t (1.6)
Condensing process m_ cw ¼ x2 m_ total hcDT

5 h6 (1.7)
1.2.2 Double-flash steam power plants

TABLE 1.2 Exergy and power plant efficiency [19].
The development of the double-flash steam geothermal
Thermodynamic Equation
power plant was to support power generation by the use
dimension Equation number
of a mixture of vapor and liquid water generated in the geo-
Specific exergy ex ¼ h(T, P) h(TO, (1.8) thermal production wells [21]. A double-flash power plant
PO) TO[s(T, P) is considered more advantageous than a single-flash power
s(TO, PO)]
plant, as the former can generate 25% more output power
Exergetic power _ ¼ m_ total ex
Ex (1.9) than the latter under the same geothermal fluid conditions
_ _ [13]. However, double-flash steam power plant technology
Entire power plant u ¼ WE_net ¼ WE_e (1.10)
efficiency is more complex and its operation and maintenance are
more expensive than single-flash power plants. Never-
theless, the efficient use of the geothermal resource is a
pointer that a secondary flash process is valuable. The use
of a second pressure drop in a secondary flash process
geothermal fluid for a given pressure (P), temperature (T), (second separator), after the first pressure drop, supports
ambient pressure (PO). and ambient temperature (TO). the production of extra vapor from the separated liquid
Eq. (1.9) shows the exergetic power, also known as the exiting the first separator. Further, the coupled turbine gen-
maximum theoretical thermodynamic power, which is the erator is able to produce additional power due to the supply
total geothermal mass flow rate times the exergy. Finally, of lower-pressure steam [22] or to a turbine depending on
the exergy efficiency of the entire power plant is given by the configuration [23]. The double-flash power plant’s com-
Eq. (1.10) [19]. plete exergy performance is optimally boosted due to the
There are several environmental impacts of single-flash separator of the geothermal steam-water, which is the prin-
geothermal power plants [15]. Locations such as the cooling cipal technological development of this power plant
tower, the ejector vents, the pipeline drains, the steam technology.
tramps, the silencers, the mufflers, and the wellhead, which Upon comparison to a single-flash system (Fig. 1.1), a
offers a structural interface between the wells and the pro- double-flash configuration (Fig. 1.3) uses a dual-admission
duction system, are the prime areas of pollution [18]. The turbine and a low-pressure separator. For the purpose of
blending of noncondensable gases such as methane smooth combination with the expanded high-pressure
(CH4), hydrogen sulfide (H2S), and carbon dioxide (CO2) steam, the low-pressure steam is supplied to the turbine at
from the steam of geothermal reservoirs is considered a the right stage [15]. Fig. 1.3 presents the energy conversion
main environmental concern. These gases are, however, process in a double-flash steam geothermal power plant.
subjected to treatment and isolation before being discharged The double-flash steam power process commences at
into the atmosphere [20]. Further, in spite of its CO2 emis- station 2; the source of the inlet temperature is the corridor
sions, the GHG emissions from a single-flash geothermal of the geofluid. The first flashed-steam process occurs
power plant (0.06 kg CO2/kWh) are significantly lower than between stations 1 and 2, when the pressure drops and the
the traditional coal-fired (1.13 kg CO2/kWh) or natural-gas- fluids begin to boil (mixture steam-liquid) before reaching
fired power plants (0.59 kg CO2/kWh) [13]. With respect to the separator at station 2. The fluid mixture is then separated
footprint, the land requirements of a coal-fired power plant into the brine and high-pressure steam. The mineral-laden
(40,000 m2/MW) and a solar photovoltaic power plant brine hot water (station 3) is then downwardly controlled
(66,000 m2/MW) are much higher than the 1200 m2/MW to low-pressure (station 8) and high-pressure steam (station
required for a single-flash plant [15]. In general, the loss 5) with the support of a separator. This prompts the second
of characteristic beauty, ozone-depleting substances, land flashed-steam process. The second pressure drop at station 9
and water utilization, visual and noise pollution, and water will lead to the production of a steam-brine mixture and the
contamination are some of the other environmental brine is collected by the low-pressure separator. The second
concerns associated with geothermal power plants [10]. steam is injected into the system at station 9 and the turbine
Strategies to mitigate the environmental impacts of collects the second fresh low-pressure steam. At station 5,
single-flash geothermal power plant as proposed in [20] the first high-pressure steam gains access to the turbine after
include mufflers and silencers to abate noise pollution, the initial steam injection. The induced motion of the dual-
air-cooled condensers, reinjection for surface water, and injection turbine, connected to a generator, generates elec-
preventing expansion of geothermal projects into national trical energy. The condenser pressure at station 6, connected
parks. By and large, the emissions from geothermal power to the turbine, is the location where the steam expansion
plants are inconsequential compared to fossil-fuel conven- happens [15]. With respect to the process design, the first
tional power plants. stage admission or injection of the turbine should have
PW Production well SV Stop valve MR Moisture remover

S Silencer SE Steam jet ejectors ST Steam tramp
WV Well valves C Condenser CV Control valve
BCV Ball check valve CP Condensate pump TV Throttle valve
IW Injection well HPT High-pressure turbine G Generator
CWP Condensed water pump LPT Low-pressure turbine EG Electric grid
HPCS High-pressure cyclone LPFS Low-pressure flash WH Wellhead
separator separator
FIG. 1.3 Double-flash geothermal power plant with a dual admission turbine [15, 17].
the same pressure difference between the high and low sep- (1.18) are used to calculate the mass flow rate of brine pro-
arators [24]. The high-pressure stage mass flow is expected duced at high pressure (m_ hpb , at state 3) and low pressure
to be lower than the low-pressure stage mass flow. The (m_ lpb , at state 7). The low-pressure turbine stage (at state
residual hot fluids at station 6 are condensed by using an 9) accommodates the high-pressure and low-pressure
air-cooled condenser. Cool air is supplied at station c1 steams together. With the aid of Eqs. (1.15)–(1.18), four
and exited at station c2. Finally, the residual brine from values are appraised: the disposed waste liquid, the
the second flashed process at station 10 and the condensed
fluid from station 7 is reinjected into the system at station 4
(Fig. 1.3).
The temperature-entropy (T-s) of a double-flash power
plant is presented in Fig. 1.4. The two flash processes that
exist in states 1–2 and 3–6 are significant, and they are
studied separately as a single process [15]. To ascertain
the quantity of steam generated in the separators at each
flashed process (x2 in states 1–2 and x6 in states 3–6, the sep-
aration process), Eqs. (1.11)–(1.14) in Table 1.3 are applied.
Further, the evaluation of the steam at state 2 and the
brine at state 6, obtained from different separators at the
high- and low-pressure stages, was achieved by using four
equations, as shown in Eqs. (1.15)–(1.18). Again,
Eqs. (1.15), (1.17) give the mass flow rate of steam gen-
erated at high pressure (m_ hps , at state 5) as well as at low FIG. 1.4 Temperature-entropy process diagram for a double-flash power
pressure (m_ lps , at state 8), respectively. Also, Eqs. (1.16), plant with a dual admission or injection turbine [15].
TABLE 1.3 Thermodynamic equations for double-flash geothermal power plants [14, 15].
State Main characteristics Equation Equation number

Flash process 1 Constant enthalpy h1 ¼ h2 (1.11)
Separation process 1 Constant pressure x2 ¼ hh24 h3
h3
(1.12)
Mixture of liquid plus vapor
Flash process 2 Constant enthalpy h3 ¼ h6 (1.13)
Separation process 2 Constant pressure x6 ¼ hh38 h7
h7
(1.14)
Mixture of liquid plus vapor
Mass flow rate of steam High pressure m_ hps ¼ x2 m_ total ¼ m_ 4 ¼ m_ 5 (1.15)
generated
Mass flow rate of brine High pressure m_ hpb ¼ ð1 x2 Þm_ total ¼ m_ 3 ¼ m_ 6 (1.16)
produced
Mass flow rate of steam Low pressure m_ lps ¼ ð1 x2 Þx6 m_ total ¼ m_ 8 (1.17)
generated
Mass flow rate of brine Low pressure m_ lpb ¼ ð1 x2 Þð1 x6 Þm_ total ¼ m_ 7 (1.18)
produced
Turbine expansion High-pressure stage (Eqs. 1.22–1.23 are the whpt ¼ h4 h5 (1.19)
process Baumann rule)
hpt ¼ hh44h
h5
5s
(1.20)
W_ hpt ¼ m_ hps whpt ¼ x2 m_ total whpt (1.21)

h7 (1.22)
h4 A 1
h8 h7
h5 ¼ A
1+
h8 h7
A ¼ 0.425(h4 h5s) (1.23)
Turbine expansion Low-pressure stage m_ 5 h5 + m_ 8 h8 ¼ ðm_ 5 + m_ 8 Þ h9 (1.24)
process
h9 ¼ x2 hx52 ++ ðð1x2 Þx6 h8
1x2 Þx6
(1.25)
wlpt ¼ h9 h10 (1.26)
W_ lpt ¼ m_ 9 ðh9 h10 Þ (1.27)

h11 (1.28)
h9 A x9
h12 h11
h10 ¼ A
1+
h12 h11
A ¼ 0.425(h9 h10s) (1.29)
lpt ¼ hh99h
h10
10s
(1.30)
W_ total ¼ W_ hpt + W_ lpt (1.31)
W_ e , gross ¼ g W_ total (1.32)
condenser heat dissipated, the cooling water heat losses, and Thus, for a typical double-flash power plant with the
the turbine power production. high-pressure (hpt) and low-pressure (lpt) processes, two
This system is applied for the illustration of the two isentropic turbine efficiencies are derived by using
turbine expansion processes. Eq. (1.19) is the representation Eq. (1.20), and a low-pressure process (lpt) by using
of the first turbine expansion process producing work (whpt) Eq. (1.30). The first turbine stage power produced at high
that occurs between states 4 and 5. Eq. (1.26) describes the pressure (W_ hpt ) and the second stage power produced at
second turbine expansion process producing work (wlpt). low pressure (W_ lpt ) are defined by using Eq. (1.21) and
Eq. (1.27), respectively. Eq. (1.31) provides the aggregate converting the flashed generation systems into a dry-steam
turbine power produced (W_ total ), which is an addition of system. Considering high enthalpy system configurations,
individual turbine stage power generated. Lastly, as dry-steam geothermal power plants are the most efficient
explained in Eq. (1.32), the efficiency of the generator because the hydrothermal reservoirs support these configu-
(g) impacts the electrical power (W_ e, gross ). The efficiency rations with vapor-dominant geothermal fluid at high tem-
of the overall power plant, the incoming geothermal fluid peratures [25, 26]. The coupled turbine generator is able
exergy, the environmental impacts, and the deployed to generate electrical energy using the steam supplied
equipment are similar to that of the single-flash process directly from the production well [10].
[24, 25]. In dry-steam power generation, between 50% and 70%
of the geothermal fluid available work (exergy) is converted
into electrical power [25]. Upon comparison with the steam-
1.2.3 Dry-steam power plants
flashed process, the dry steam has a simpler concept and
Studies have shown that several locations around the globe requires centrifugal cyclones to separate particulate matters
are endowed with geothermal dry-steam, particularly in such as rock chippings and dust [25]. Similarly, the con-
places such as the geysers in the United States and Lar- densate is eliminated by using drain pots, and the last
derello, Italy. Both places have the two largest dry-steam moisture is eliminated to achieve high-grade steam in the
reservoirs. However, places such as Cove Fort, Utah, United turbine. A Venturi meter is also needed for the accurate cal-
States; Wairakei, New Zealand; Matsukawa, Japan; and ibration of the turbine steam flow rate [13].
Kamojang, Indonesia are characterized by limited dry steam The mechanism of conversion of energy in the dry-steam
[16, 20]. In the event that a geothermal reservoir dries, power plant process is described in Fig. 1.5. Both single-
Zarrouk and Moon [16] discussed the possibility of flash and dry-steam (geothermal fluid) processes share
FIG. 1.5 Dry-steam geothermal power plant [9, 17].

similar features of the whole power generation cycle, from 1.2.4 Binary-organic Rankine cycle and
the production wells to the production turbine [15]. For both Kalina cycle power plants
smaller or larger units of single flow or double flow, a single
pressure is performed by the blading turbine of impulse- The binary geothermal power plant (B-GPP) generates elec-
reaction. Based on the graphs, Fig. 1.1 (single flash) shares trical energy from a secondary separated process. Pre-
the same similarity with Fig. 1.5 with a particulate remover heating of the working fluid is involved and heat is lost
rather than a cyclone separator. upon contacting the geothermal fluid [10]. Geothermal
Fig. 1.6 is the T-s thermodynamic state of the dry-steam resources with a temperature range of 20–150°C [25] or
system. At state 1, saturated steam or lightly superheated 85–170°C [27] are well suited for binary configurations
steam is generated in the production wells. The expansion [25]. A higher temperature range provide thermal stability
of the turbine occurs between states 1 and 2 while the of the working fluid while the lower temperatures are more
cooling process is attained between states 2 and 3, where feasible in terms of technoeconomic and financial factors.
an emission of heat via the condenser occurs. The single- Further, the impacts of corrosion and scaling are not
flash geothermal power plant system is equivalent to the apparent at high temperature, as there is no contact between
thermodynamic study [18]. Table 1.4 shows the equations the power generation equipment and the geofluid. Under a
in analyzing the dry-steam power plants. In terms of impacts conventional Rankine cycle, there is the functionality of the
on the environment, the single-flash geothermal power plant secondary fluid (working fluid) in the binary system [28],
process has a lower environmental impact than flashed and the binary cycle is identified as the Organic Rankine
power plants, as the system does not use mineral-laden Cycle (ORC) due to the organic nature of the working fluid.
brine [15]. Binary power plants are versatile and the functionality of
the power plant is decided by the secondary cycle. Different
types of configurations of binary power plants are in oper-
ation, including B-GPP using an ORC with an internal heat
exchanger (IHE), B-GPP with a regenerative ORC, and
B-GPP with a regenerative ORC using IHE [29]. In 1982,
Kalina patented a variation in B-GPP [30]. The working
fluid used in the Kalina cycle consists of water and ammonia
and can be used in different compositions to suit various
configurations [31]. A thermal efficiency of 30%–40% is
achievable and is considered more efficient than that of
an ordinary B-GPP [28].
A closed loop of a thermodynamic Rankine Cycle used
for the energy conversion system of a basic binary geo-
thermal power plant is shown in Fig. 1.7. Harvesting the
geothermal fluid via the production wells (PW) and then
transporting it through various primary cycle components
necessitates that pumping systems are deployed. The
scouring and erosion of pipes and tubes can be prevented
by extracting sand from the geofluid by employing sand
FIG. 1.6 Temperature-entropy (T-s) process diagram for a dry-steam removers (SR). Finally, an evaporator (E) and a preheater
power plant with saturated steam at the turbine inlet [15, 18]. (pH) are used for continuous fluid flow while the geo-
thermal fluid is reinjected into the reservoir near the
injection well (IW) by using an injection pump (IP).
TABLE 1.4 Thermodynamic equations in the dry-steam
Regarding the working cycle, two heating-boiling pro-
process for turbine expansion process [15].
cedures are included in the working fluid. The PH is the
location of the boiling point of the working fluid. Upon
Equation Equation number contact of PH with E, the working fluid becomes a saturated
wt ¼ h1 h2 (1.33) vapor. This results in the expansion and condensation of the
working fluid in the turbine. The working fluid is then
t ¼ hh11h
h2
2s
(1.34)
returned to the evaporator, thereby concluding the loop
W_ t ¼ m_ s wt ¼ m_ s ðh1 h2 Þ (1.35) process and beginning the process again [31]. To prevent
steam eruption and calcite scaling within the pipes, moni-
W_ e ¼ g W_ t (1.36)
toring the geothermal fluid above the flash pressure point
is necessary [13]. Thus, the low-temperature geothermal
FIG. 1.7 Basic binary geothermal power plant [17, 18].
resources are enabled by this binary-type energy conversion emergence of the working fluid as saturated vapor initiates
setup and by relying upon specialized highlights to attain the process repeatedly [14, 15].
amazingly high plant performances [32]. Regarding the condenser, the turbine, and the feed
Fig. 1.8 presents the pressure-enthalpy of a binary geo- pump, the flash and dry-steam plants share similar
thermal power plant. At state 1, the working fluid at the sat-
urated vapor point accesses the turbine and facilitated the
expansion and production of work, and this marks the
beginning of the thermodynamic process. Based on the
work produced, electrical energy is generated by the gen-
erator. At state 2, after the expansion process of the turbine,
the temperature and pressure of the saturated vapor reduce.
At state 3, a temperature reduction occurs as the working
steam-fluid enters the condenser, and this eventually culmi-
nates into fluid condensation. The application of cooled
water from the air-cooled tower initiates the cooling process
of the working fluid between states 3 and 4. The transfor-
mation of the working fluid state into a saturated liquid is
achieved by this cooling phase. At states 5 and 6, the
working saturated liquid-fluid is pumped back to the pre- FIG. 1.8 Pressure-enthalpy diagram of a binary geothermal power plant
heater and evaporator, respectively. At state 1, the [15].
The analysis of geothermal fluid and the working fluid

TABLE 1.5 Thermodynamic equations for binary evaporation heat transfer rate is shown in Eq. (1.46). The
geothermal power plants [15]. known brine inlet temperature is represented as Ta; Tb is
Equation obtained from the pinch-point temperature (minimum tem-
State Equation number perature difference between two fluids supplied by the man-
ufacturer) and the known T5. Lastly, Eqs. (1.48)–(1.50) give
Turbine w1 ¼ h1 h2 (1.37)
the performance assessment parameters of the cycle. Based
expansion
process t ¼ hh11h
h2 (1.38) on the input of thermal power (Q_ PH=E ) and the thermal
power rejected (Q_ c ), Eq. (1.48) is the presentation of the
2s
W_ t ¼ m_ wf wt ¼ m_ wf t ðh1 h2s Þ (1.39)

thermal efficiency of the entire cycle (th) [15, 19].
W_ e ¼ g W_ t (1.40) During the design process of a B-GPP, choosing the
working fluid is critical and entails considering the geofluid
Condensing Q_ c ¼ m_ wf ðh2 h3 Þ (1.41)
process
and working fluid thermodynamics characteristics as well as
safety, health, and the effect on the environment [15]. The
Feed pump W_ p ¼ m_ wf ðh4 h3 Þ (1.42) economy and the efficiency of B-GPP are described by the
Heat m_ b ðha hc Þ ¼ m_ wf ðh1 h4 Þ (1.43) working fluid adoption [33]. Table 1.6 shows different
exchange working fluids and explicitly explains how working fluid
PH: m_ b c b ðTa Tc Þ ¼ m_ wf ðh5 h4 Þ (1.44)
process at E critical temperatures (CT) and critical pressures (CP) are
and PH E: m_ b c b ðTa Tc Þ ¼ m_ wf ðh1 h5 Þ (1.45) extremely lower in contrast to water. Different contem-
Q_ E ¼ m_ b c b ðTa Tb Þ ¼ (1.46) porary binary technologies have emerged, promoting
m_ wf ðh1 h5 Þ advancement at higher performances via the flexible
adoption of a secondary cycle in B-GPP [24]. Studies by
DiPippo [15] and Valdimarsson [34] describe various other
Q_ PH ¼ m_ b c b ðTb Tc Þ ¼ (1.47) binary configurations, including the dual-pressure binary
m_ wf ðh5 h4 Þ cycle, the dual-fluid binary cycle, the Kalina binary cycles,
and regenerative ORC.
To adopt ORC-GPP, different methods have been inves-
_ tigated regarding working fluid. A work by Quoilin [35] put
th ≡ QW
_
net (1.48)
PH=E
forward an approach for the selection of the working fluid
W_ net ¼ Q_ PH=E Q_ c ; (1.49) and an expansion process in the same system. For any
Q_ PH=E ¼ Q_ E + Q_ PH ORC process, the working fluid and expansion mechanism
are adopted by the application of this method. Mikielewicz
th ¼ 1 hh21 h3
h4
(1.50)
and Mikielewicz [25] studied 20 working fluids for an ORC
and concluded that R123 and R141b possess the most suit-
ability for small-scale operations. Regarding the adoption of
the best applicable working fluid for an ORC, extensive
thermodynamic analyses. The equation for the analysis of a
binary geothermal power plant is captured in Table 1.5. The
turbine expansion process work generated is computed in
TABLE 1.6 Working fluids commonly used in binary
Eq. (1.37) while the isentropic turbine efficiency (t) is
geothermal plants [15].
described in Eq. (1.38). Similarly, in Eqs. (1.39), (1.40),
the power of the turbine (W_ t ) as well as the power of the gen- CT (° PC PS @
erator (W_ e ) are evaluated as m_ wf connotes the mass flow rate Fluid Formula C) (MPa) 300 k MPa
of the working fluid and g is the efficiency of the generator. Propane C3H8 96.9 4.24 0.9935
Q_ c is the description of the working fluid heat discarded due
to cooling during the condensation process. Eq. (1.42) pre- i-Butane i-C4H10 135.9 3.69 0.3727
sents the power transferred to the working fluid from the n-Butane C4H10 150.8 3.72 0.2559
feed pump (W_ p ). A steady flow, well-insulated PH and E i-Pentane i-C5H12 187.8 3.41 0.0975
as well as insignificant potential and kinetic energy are
the three propositions useful in analyzing the heat exchange n-Pentane C5H12 193.9 3.24 0.0738
process [15]. Eq. (1.43) is administered to the thermody- Ammonia NH3 133.6 11.63 1.061
namic system where a symbolizes the geothermal fluid inlet Water H2O 374.1 22.09 0.003536
while b represents the geothermal fluid after E and c
after PH.
indicators are provided in [35], namely thermodynamic per- concentrating parabolic collector hybridized to a single-
formance, isentropic saturation vapor curve, high vapor and double-flash geothermal power plant for various
density, low viscosity, high conductivity, evaporating geothermal reservoir situations. Based on their findings,
pressure, condensing gauge pressure, high-temperature sta- the hybrid single-flash configuration generates an increment
bility, melting point, low ozone-depleting potential, low of 20% extra power output, and the quantity of the geo-
greenhouse warming potential, availability, and low cost. thermal fluid deployed from reservoirs in the hybrid
Astolfi [36] conducted a comprehensive study of binary double-flash configuration dropped by 19%. Ayub and
ORC power plants focusing on harvesting low-medium Mitsos [38] integrated two existing simulations, an ORC
temperature geothermal sources [37]. The above authors geothermal model and a low-temperature solar technology,
examined 54 working fluids in six dissimilar cycle config- and the results showed how the hybrid system’s levelized
urations and concluded that the optimal fluid is decafluoro- energy cost was lowered by 2% while the ORC geothermal
butane at a low temperature of 120°C while at a higher configuration’s levelized energy cost was reduced by 8%.
temperature of 180°C, R236ea has been the optimum fluid. Zhou [39] investigated hybrid geothermal energy
systems. The result of the solar-geothermal viability inves-
tigation indicates an increment in the efficiency of the net
1.2.5 Advanced geothermal energy electrical output of the power plant by 12.7% as well as
an increment in the performance of the thermal plant by
conversion systems—Hybrid configurations
7.5%. A related study in [40] showed the possibility of min-
Concerning configurations of geothermal energy con- imizing the cost of electrical energy generation by 20% via
version processes, three innovative technologies were sug- the deployment of a solar-geothermal power plant compared
gested: hybrid single-flash and double-flash systems, hybrid to using a standalone enhanced geothermal system. For a
flash-binary systems, and hybrid fossil-geothermal systems subcritical and supercritical ORC solar-geothermal plant,
[15]. Also, the amalgamation of geothermal technologies the yearly electricity production increases by 15% and
with biomass, waste-to-energy systems, fuel cells, and solar 19% with the exergy of the solar fraction above 66%
thermal systems is attracting significant attention [12, 38]. [39]. Recently, a novel solar-geothermal hybrid power plant
Thain and DiPippo [12] also stated the principal signifi- was proposed based on the hybridization of an existing geo-
cance of hybrid geothermal as other clean energy technol- thermal binary cycle with a solar-powered steam-Rankine
ogies under the following factors: impacts on the topping cycle [41]. This hybridization can produce approx-
environment, electrical energy cost, exergy, plant perfor- imately 60% more electricity per day in hot seasons,
mances, the performance of turbo-machinery, the viability decreasing the use of geothermal resources by 17% per year.
of the technoeconomic aspects, and the investment risk. Hybrid geothermal-fossil fuel power plant configura-
With respect to the binary power plant’s environmental tions provide substitutes to minimize the use of fossil fuels
impact, the geothermal fluid is evacuated and returned to and greenhouse gas emissions for low-enthalpy geothermal
the reservoir. There is no chemical or physical interaction resources. Zhou [39] examined a 500 MW hybrid
of the working fluid with the environment. The environ- geothermal-coal configuration with a 210°C reservoir tem-
mental impact is the only thermal pollution that occurs as perature and a 400 kg/s brine flow rate, and he showed that
a result of heat rejection along the cycle, and this is appli- 0.3 million tonnes of coal per year could be saved and
cable for direct heating purposes [20]. approximately 0.72 million tonnes of GHE per year could
The attention of many studies focuses on the hybrid con- be reduced [27]. In addition, in comparison with the stan-
figuration of various thermal and nonthermal clean energies dalone geothermal power plant, electrical energy can be
with geothermal resources [12]; nevertheless, hybrid reduced by between 33% and 87%; also, in comparison with
geothermal-fossil fuel systems have been in existence a sole coal-fired power plant, electricity production can be
[39]. The current interest of the research community is increased by approximately 19% [39].
the study of hybrid solar and geothermal energy configura- Power generation also depends on the potential of oil
tions for power plants [26, 29]. Jiang [26] conducted ther- and gas fields. In a study, 349 abandoned onshore oil and
modynamic research for a hybrid solar-enhanced gas wells were investigated by Reyes [42], and it was con-
geothermal system power plant, where the working fluid cluded that 1.7 109 kWh could be integrated into the elec-
used was CO2 in a supercritical CO2 Brayton cycle. Based tricity network of New Zealand. Likewise, a recent work in
on their conclusion, the hybrid system has higher efficiency [30] investigated three gas reserves in Croatia, and the
compared to the aggregate of the two independent off-grid results showed the possibility of the economic viability of
systems. Supplementary electricity was produced during the unexploited gas fields. A study by Davis and Michae-
peak demand hours due to the increased capacity driven lides [43] showed that South Texas untapped oil wells have
by the solar system, even as the geothermal cycle supports the potential to drive about 3 MW of electrical energy.
based-load electricity. Cardemil [29] analyzed the solar- Similar studies can be found in the literature [44].
Few studies have focused on the geothermal and biomass Acknowledgments

power plant hybrid systems. In order to achieve a higher
Diego Moya has been funded by the Ecuadorian Secretariat for Higher
power output, Thain and DiPippo [12] examined the hybrid
Education, Science, Technology, and Innovation (SENESCYT),
system of a geothermal-biomass power plant. The authors’ Award No. CZ03-35-2017; The Technical University of Ambato
findings showed an increase in net power by 32% in contrast (UTA), Award No. 1895-CU-P-2017 (Resolución HCU); and sup-
with the standalone power plants. Similarly, Moret [45] pre- ported by The Science and Solutions for a Changing Planet Doctoral
sented the findings of a study on geothermal biomass. Training Partnership, Grantham Institute, at Imperial College London.
Overall, the deployment of geothermal heat to advance the The Institute for Applied Sustainability Research (IIASUR) supports
biomass conversion system performances is proven by inno- international research on global sustainability applied to the Global
vative hybrid geothermal-biomass systems that indicate pos- South. We acknowledge the important comments and suggestions
itive synergies. A recent study also proposed a novel made by anonymous reviewers to improve the quality, clarity, and
configuration of a hybrid binary geothermal-biomass power strictness of this article. Andrea Morales and Rafaela Moya are highly
appreciated for their support during the development of the
plant [46]. This proposed configuration increased the temper-
manuscript.
ature of the geothermal fluid by 28%, minimizing the oper-
ational cost associated with the biomass.
REFERENCES
1.3 Closing remarks [1] Christensen JL, Hain DS. Knowing where to go: the knowledge foun-
dation for investments in renewable energy. Energy Res Soc Sci
This study reveals other measures of minimizing global 2017;25:124–33.
fossil fuel consumption and its environmental effects by [2] Shortall R, Davidsdottir B, Axelsson G. Geothermal energy for sus-
using a geothermal energy system in a range of power plant tainable development: a review of sustainability impacts and
configurations. An assessment study by Stefansson [47] assessment frameworks. Renew Sust Energ Rev 2015;44:391–406.
shows that a geothermal potential lower limit is expected [3] Budisulistyo D, Krumdieck S. Thermodynamic and economic
to generate 1.5 TW of electricity from the global geo- analysis for the pre-feasibility study of a binary geothermal power
thermal resource. Further, the author discovered that plant. Energy Convers Manag 2015;103:639–49.
[4] DiPippo R. Geothermal power plants: evolution and performance
around 68% of the aggregate geothermal resources have
assessments. Geothermics 2015;53:291–307.
temperatures below 130°C (mainly for direct heat uses), [5] Axelsson G, Stefánsson V, Xu Y. Sustainable management of geo-
and the extra resources are temperatures above 130°C thermal resources. In: Proceedings of the international geothermal
(appropriate for power generation). The application of conference; 2003.
low-temperature geothermal resources might be achieved [6] Chen J, Jiang F. Designing multi-well layout for enhanced geothermal
by using Binary Organic Rankine Cycle power plants. In system to better exploit hot dry rock geothermal energy. Renew
addition, studying a hybrid geothermal-biomass configu- Energy 2015;74:37–48.
ration is expedient despite the in depth research on hybrid [7] Bertani R. Geothermal power generation in the world 2010–2014
geothermal-solar thermal configurations. The increase of update report. Geothermics 2016;60:31–43.
energy output, the thermal performance, and the increase [8] Eslami-Nejad P, Ouzzane M, Aidoun Z. Modeling of a two-phase
CO2-filled vertical borehole for geothermal heat pump applications.
of the geothermal reservoir lifespan are features of both
Appl Energy 2014;114:611–20.
solar and biomass. In contrast, favorable opportunities
[9] Zarrouk SJ, Purnanto MH. Geothermal steam-water separators:
for increasing geothermal project income are attained by design overview. Geothermics 2015;53:236–54.
the direct applications of geothermal heat. The application [10] Braun GW, McCluer PH. Geothermal power generation in United
of numerous direct uses is achievable subject to the geo- States. Proc IEEE 1993;81(3):434–48.
graphic zone. The applications of the geoheat contribute [11] Kipsang C. Cost model for geothermal wells. vol. 11. Reykjavik,
to increasing the living conditions of the regions situated Icelan: United Nations University; 2014. Geothermal training pro-
at the geothermal resource due to the contribution of the gramme reports 2013.
cascade configurations (for example) to maximize the [12] Thain I, DiPippo R. Hybrid geothermal-biomass power plants: appli-
use of geoheat. Cascade applications allow the use of dif- cations, designs and performance analysis. In: Proceedings of the
ferent temperatures of the same geothermal fluid in staging world geothermal congress 2015; 2015. [cited 2017 February 2];
Available from: http://events.bioenergy.org.nz/documents/events/
and successive applications in a sequence that require
Thain-DiPippo-WGC2015-Geothermal-Biomass-Hybrid-Power-
lower temperatures downstream. Geothermal hybrid con-
Plant-FINAL-VERSION.pdf.
figurations along with direct uses (heat, air conditioning, [13] Bertani R. Geothermal power Generation in the world 2010–2014,
refrigeration, drying, evaporation, and district heating, update report. In: Proceedings of the world geothermal congress
among others)—cascade applications—are some of the 2015. International Geothermal Association; 2015.
poly-generation hybrid configurations identifiable for [14] Valdimarsson P. Geothermal power plant cycles and main compo-
future research opportunities. nents. In: Presented at “short course on geothermal drilling, resource
development and power plants” organized by UNU-GTP and LaGeo, [31] Zhang X, He M, Zhang Y. A review of research on the Kalina cycle.
in Santa Tecla, El Salvador; 2011. Renew Sust Energ Rev 2012;16(7):5309–18.
[15] DiPippo R. Geothermal power plants: Principles, applications, case [32] DiPippo R. Second law assessment of binary plants generating power
studies and environmental impact. 3rd ed. Butterworth-Heinemann; from low-temperature geothermal fluids. Geothermics 2004;33
2012. (5):565–86.
[16] Zarrouk SJ, Moon H. Efficiency of geothermal power plants: a [33] Bao J, Zhao L. A review of working fluid and expander selections for
worldwide review. Geothermics 2014;51:142–53. organic Rankine cycle. Renew Sust Energ Rev 2013;24:325–42.
[17] SmartDraw. Engineering library. San Diego, CA: Smart Draw [34] Valdimarsson P. Short course: electricity generation from low tem-
Software LLC; 2015. perature geothermal resources. In: Presented at ’WGC2015’ World
[18] Chamorro C, et al. World geothermal power production status: geothermal congress 2015, Melbourne, Australia; 2015.
energy, environmental and economic study of high enthalpy technol- [35] Quoilin S. Working fluid selection and operating maps for organic
ogies. Energy 2012;42(1):10–8. Rankine cycle expansion machines. In: Proceedings of the 21st inter-
[19] Çengel YA, Boles MA. Thermodynamics: An engineering approach. national compressor conference at Purdue; 2012.
New York: McGraw-Hill; 2015. [36] Astolfi M. Binary ORC (organic Rankine cycles) power plants for the
[20] Bayer P, et al. Review on life cycle environmental effects of geo- exploitation of medium–low temperature geothermal sources—part
thermal power generation. Renew Sust Energ Rev 2013;26:446–63. A: thermodynamic optimization. Energy 2014;66:423–34.
[21] Aikawa K, Soda M. Advanced design in Hatchobaru geothermal [37] Astolfi M, et al. Binary ORC (organic Rankine cycles) power plants
power station. In: Proceedings second UN symposium development for the exploitation of medium–low temperature geothermal
and use of geothermal resources. Washington, DC: US Government sources—part B: techno-economic optimization. Energy
Printing Office; 1976. 2014;66:435–46.
[22] DiPippo R. Geothermal energy electricity generation and environ- [38] Ayub M, Mitsos A, Ghasemi H. Thermo-economic analysis of a
mental impact. Energy Policy 1991;19(8):798–807. hybrid solar-binary geothermal power plant. Energy
[23] Yildirim N. Modelling, simulation and optimization of flashed-steam 2015;87:326–35.
geothermal power plants from the point of view of non-condensable [39] Zhou C. A fundamental study on hybrid geothermal energy systemsj
gas removal systems. In: Graduate School of Engineering and Sci- NOVA. The University of Newcastle’s Digital Repository, in School
_
ences of. Turkey: Izmir Institute of Technology; 2010. p. 178. of Engineering, Chemical Engineering. Australia: The University of
[24] Valdimarsson P. New development in the ORC technology; 2014. Newcastle; 2014.
p. 1–10. [cited 2015 14 May]; Available from: http://www.os.is/ [40] Zhou C, Doroodchi E, Moghtaderi B. An in-depth assessment of
gogn/unu-gtp-sc/UNU-GTP-SC-18-18.pdf. hybrid solar–geothermal power generation. Energy Convers Manag
[25] Mikielewicz D, Mikielewicz J. A thermodynamic criterion for 2013;74:88–101.
selection of working fluid for subcritical and supercritical domestic [41] Bonyadi N, Johnson E, Baker D. Technoeconomic and exergy
micro CHP. Appl Therm Eng 2010;30(16):2357–62. analysis of a solar geothermal hybrid electric power plant using a
[26] Jiang P-X. Thermodynamic analysis of a solar–enhanced geothermal novel combined cycle. Energy Convers Manag 2018;156:542–54.
hybrid power plant using CO2 as working fluid. Appl Therm Eng [42] Reyes AG. Abandoned oil and gas wells: A reconnaissance study of
2017;116:463–72. an unconventional geothermal resource. GNS Science; 2007.
[27] Zhou C, Doroodchi E, Moghtaderi B. Assessment of geothermal [43] Davis AP, Michaelides EE. Geothermal power production from aban-
assisted coal-fired power generation using an Australian case study. doned oil wells. Energy 2009;34(7):866–72.
Energy Convers Manag 2014;82:283–300. [44] Liu J, et al. Feasibility of combination of CO2 geological storage with
[28] Kopunicová M. Feasibility study of binary geothermal power plants in geothermal-type water-soluble gas recovery in Yinggehai Basin,
Eastern Slovakia, analysis of ORC and kalina power plants. In: The China. Int J Greenhouse Gas Control 2016;45:139–49.
School for Renewable Energy Science. University of Iceland & the [45] Moret S. Integration of deep geothermal energy and woody biomass
University of Akureyri; 2008. conversion pathways in urban systems. Energy Convers Manag
[29] Cardemil JM. Thermodynamic evaluation of solar-geothermal hybrid 2016;129:305–18.
power plants in northern Chile. Energy Convers Manag [46] Briola S, Gabbrielli R, Bischi A. Off-design performance analysis of a
2016;123:348–61. novel hybrid binary geothermal-biomass power plant in extreme envi-
[30] Kurevija T, Vulin D. High enthalpy geothermal potential of the deep ronmental conditions. Energy Convers Manag 2019;195:210–25.
gas fields in Central Drava Basin, Croatia. Water Resour Manag [47] Stefansson V. World geothermal assessment. In: Proceedings of the
2011;25(12):3041–52. world geothermal congress; 2005.
Chapter 2
Global value chain and manufacturing

analysis on geothermal power plant
turbines
Sertaҫ Akar, Chad Augustine, and Parthiv Kurup
National Renewable Energy Laboratory (NREL), Golden, CO, United States
2.1 Global geothermal energy market WCCT, or ACC is then chosen to complement the turbine
size and design. As an example, the Salton Sea Unit 5 geo-
The global geothermal power market grew by 13% between thermal steam turbine in Imperial Valley, Southern Cali-
2015 and 2019, which increased the total installed geo- fornia, is designed and optimized for 58.32 MWe [5].
thermal power capacity from 13.65 GWe in 2015 [1] to Custom design turbines have relatively higher manufacturing
15.41 GWe in 2019 [2]. The countries with the highest set-up costs, longer lead times, and higher capital costs than
geothermal installed capacity by the end of 2019 were the the standard design turbines manufactured in larger volumes.
United States, Indonesia, the Philippines, Turkey, New However, turbines produced in standard increments and in
Zealand, Mexico, Italy, Kenya, Iceland, and Japan larger manufacturing volumes could result in lower costs
(Fig. 2.1). Between 2005 and 2015, 190 new geothermal per turbine.
power plants were installed around the world, where 62% The current manufacturing process for geothermal tur-
were binary-cycle plants, 31% were flash-cycle plants, bines is made to order. In other words, every order is a
and 7% were dry-steam plants [3]. custom design based on geothermal fluid properties. The
The number of installed geothermal power plants is challenges of geothermal fluid chemistry force designs to
expected to grow and reach about 18.4 GWe by 2021, based use special corrosion-resistant metals that are more
on forecasts [1] and pipeline projects [4] (Fig. 2.2). This expensive than standard metals used in fossil fuel-powered
could create a market demand for a diverse mix of geo- turbines. Additionally, the high fixed capital costs of
thermal turbine types. Recently, it is unclear whether the resource development and low power purchase agreement
expected additional capacity increases and the demands (PPA) prices lead developers to maximize resource utili-
are enough to increase the manufacturing volume of both zation by customizing their turbines. The customization
binary-cycle and flash-cycle power plant turbines. design factors result in greater manufacturing set-up costs,
However, based on the information about proposed projects extensive engineering, and a higher lead time (up to
and resource assessments, a significant annual power 18 months) from initial design to installation. In turn, these
capacity addition between 0.75 and 1 GWe can be expected factors may impact developers’ returns and decrease the
in the global market. It is very promising that this growth in attractiveness of deploying geothermal energy.
the geothermal market will allow standardization in turbine There are two major geothermal turbine technologies:
design, rather than the customized turbines that are being flash cycle steam turbines and binary cycle turboexpanders.
manufactured today. This increase will create a modularity The global steam turbine market is expected to increase
in the geothermal market, which will be adapted to the geo- from $14.5 billion in 2013 to $17.4 billion by 2020, with
graphic diversity of projects to offer an economy of scale. an annual growth rate of 2.6% over this period [6].
However, the market share of geothermal power plants
constitutes a small portion of the global steam turbine
2.1.1 Global value chain and trade flow market. Annual global orders for steam turbines are broadly
Geothermal project developers customize the size of the stable at around 100 GW, and geothermal steam turbines
power plant to fit the resource being developed. Geothermal constitute only 1%–2% of the total annual demand [6].
power plant turbines are designed to optimize efficiency. Usually, large coal-fired, natural gas-fired, and nuclear
The best utilization of geothermal resources such as HX, power plants drive the market. Major manufacturing
Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00007-X

FIG. 2.1 Global geothermal installed capacity for the top 10 countries by the end of 2019. (Data Source: Think GeoEnergy. The Top 10 Geothermal
Countries 2019—based on installed generation capacity (MWe). Think GeoEnergy - Geothermal Energy News, Jan. 27, 2020. http://www.thinkgeoenergy.
com/the-top-10-geothermal-countries-2019-based-on-installed-generation-capacity-mwe/ (Accessed 28 January 2020).)
20,000
Turboexpander (Binary) MW
Steam Turbine (Flash + Dry Steam) MW
Total installed Capacity (MWe)
15,000
10,000
5,000
0
2005 2007 2009 2011 2013 2015 2017 2019 2021P
FIG. 2.2 Historical, current, and projected global installations of geothermal power plant turbines. P, projection. (Data displayed to represent the median
figures that have been compiled from GEA. Annual U.S. & global geothermal power production report. Geothermal Energy Agency; 2016, Bertani R.
Geothermal power generation in the world 2010–2014 update report. Geothermics 2016; 60:31–43. https://doi.org/10.1016/j.geothermics.2015.
11.003, BNEF. Geothermal market outlook report. Bloomberg New Energy Finance; 2016.)
locations for geothermal steam turbines are Japan, Italy, the (from biogas and landfill gas), and concentrating solar
United States, France, Mexico, Russia, India, and China, power (CSP), over the last decade. While bioenergy has
where Japan accounted for 82% of the global manufacturing the greatest number of ORCs installed (for WHR with
market between 2005 and 2015 [1, 4, 7–10]. smaller installed sizes), geothermal power plants con-
The second type of turbine technology is turboex- tributed 71% of all ORC installed capacity in the world
panders, which are mostly utilized in organic Rankine between 2005 and 2016 (Fig. 2.3), as bioenergy and
cycle (ORC) binary cycle geothermal plants. Apart from WHR followed with 15% and 13.7%, respectively [11].
geothermal energy applications, the ORC technology The main manufacturing locations for binary cycle tur-
has also been used for other commercial applications, such boexpanders are Israel, the United States, Italy, and
as waste heat recovery (WHR), bioenergy production Germany; Israel accounts for 74% of the geothermal
Global value chain and manufacturing analysis Chapter 2 19
FIG. 2.3 Overview of global ORC turboexpander market 2005 and 2016 (lab-scale prototypes and installed capacity lower than 50-kilowatt electric
(kWe) have not been included). (Data modified from Tartiere T. World overview of the organic Rankine cycle technology. 2016. https://orc-world-
map.org/index.html (Accessed 22 January 2020).)
binary cycle turboexpander manufacturing market. Italian Turkey has been the fastest-growing market since the
turboexpander manufacturers have increased their market last decade. The total installed geothermal power capacity
share significantly in the last couple of years [1, 4, 7–10]. is 1.53 GWe as of 2019 and it has a capacity target of
The global trade flow of both geothermal steam turbines 2.0 GWe, including projects in the pipeline [15]. Turkey
and ORC turboexpanders between 2005 and 2015 can be implemented a renewable energy law in 2010 to reach its
seen in Fig. 2.4. target for increasing the share of renewables up to 30% of
The United States has the highest proven geothermal the energy mix by 2023 [16]. The Turkish FIT for geo-
resource capacity, and it is one of the major players in the thermal power plants is 10.5 ¢/kWh. The FIT applies for
geothermal power plant turbines and technologies market. 10 years of power generation, and producers also benefit
The current installed geothermal capacity of the United from an 85% discount on transmission costs for the 10 years
States is 3.68 GWe, with an additional 23 MW just added [16]. The 2010 Renewable Energy Law also includes bonus
before the end of 2019. The geothermal installed capacity payments for hardware components made in Turkey to
has been growing at a rate of about 2% per year and is pro- support and boost the national manufacturing sector. Com-
jected to exceed 3.9 GWe by 2022 [12]. A comprehensive panies that rely on locally produced equipment or compo-
study of the US geothermal market by the National nents receive a bonus FIT, which is fixed at 1.3 ¢/kWh
Renewable Energy Laboratory (NREL) suggests that for turbines, 0.7 ¢/kWh for generators, and 0.7 ¢/kWh for
additional power plants may come online in the next 5 years pumps and compressors [16] The FIT has increased the
if existing barriers can be removed to expedite project interest of developers and manufacturers in domestic
development [13]. manufacturing. The total FIT for geothermal could reach
Indonesia has the second-highest installed geothermal 13.2 ¢/kWh with 10 years of a purchasing guarantee. The
capacity, and it also has a fast-growing demand for elec- FIT is applied to all geothermal power plants that come
tricity. Indonesia’s current installed geothermal power online through the end of 2020.
capacity is 2.13 GWe, and the government has ambitious Another important market is Kenya, which reached
plans for 6.50 MWe of geothermal development by 2025 0.86 GWe of installed geothermal power capacity in 2019
[14]. Indonesia also has a high feed-in-tariff (FIT) policy, by adding 193 MWe of extra capacity [2]. Kenya is currently
which ranges from 12.6 to 26.2 ¢/kWh [14]. in a very ambitious phase of development with an aggressive
FIG. 2.4 Global trade flow map of geothermal turbines between 2005 and 2015. (Data Source: NREL industry outreach, GEA. Annual U.S. & global geothermal power production report. Geothermal
Energy Agency; 2016, Bertani R. Geothermal power generation in the world 2010–2014 update report. Geothermics 2016; 60:31–43. https://doi.org/10.1016/j.geothermics.2015.11.003, BNEF. Geo-
thermal market outlook report. Bloomberg New Energy Finance; 2016, BNEF. Q2 2013 geothermal market outlook report. Bloomberg New Energy Finance; 2013, BNEF. H2 2014 geothermal market
outlook report. Bloomberg New Energy Finance; 2014, BNEF. H1 2015 geothermal market outlook report. Bloomberg New Energy Finance; 2015, GEA. Annual U.S. & global geothermal power pro-
duction report. Geothermal Energy Agency; 2015, Graphic Credit: Billy Roberts (NREL).)
construction pipeline of new projects in several geothermal 2.2.1 Methodology for manufacturing
resource areas. The total estimated resource potential of the analysis
country is around 10GWe [1].
2.2.1.1 Manufacturing process flow
The manufacturing cost model includes three main steps: (1)
2.2 Manufacturing analysis Materials (used as raw and processed), (2) manufacturing (in-
house machining and outsourced parts), and (3) final
A bottom-up cost model includes a mapping of all compo- assembly. The final product could be either an ORC turboex-
nents that make up a system (i.e., labor, material, pro- pander or a geothermal steam turbine.
cesses, machining, and the balance of the system). The
bottom-up manufacturing cost model developed (and
highlighted next) for geothermal turbines considers the
materials, manufacturing steps, equipment, and assembly 2.2.1.2 Materials
of turbine subcomponents. The process flow diagram in The most common corrosion-resistant materials used for
Fig. 2.5 highlights the raw materials, the required machining the impellers are titanium or stainless steel; the
manufacturing processes and equipment, and the utility shaft is produced from a stronger material such as a forged
requirements that are inputs to the cost model. The raw nickel alloy or Inconel. Geothermal fluids contain dissolved
metals required for preprocessing are iron ore, carbon, carbon dioxide (CO2), hydrogen sulfide (H2S), ammonia
chromium, molybdenum, nickel, titanium, and aluminum (NH3), and chloride (Cl) ions that can cause corrosion of
while the processed metals are stainless steel, Inconel metallic materials. The main corrosion problems are pit cor-
(nickel) alloys, and titanium alloys [17, 18]. In addition rosion, cracking corrosion, breaking with stressed cor-
to metals, epoxy-based refined plastics are used for insu- rosion, breaking with sulfur stressed corrosion, corrosion
lation and sealing purposes. between the particles, and wearing corrosion [18].
FIG. 2.5 Manufacturing process flow diagram for geothermal power plant turbines.
FIG. 2.6 World steel production, units are a million metric tons per year. (Data Source: World Steel information system Steel Dynamics. 2015
Annual report. Steel Dynamics Inc.; 2015. Available from: https://s3.amazonaws.com/b2icontent.irpass.cc/2197/165986.pdf?
AWSAccessKeyId¼1Y51NDPSZK99KT3F8VG2&Expires¼1580257699&Signature¼9zZjMvMMB3ob07MYrZq%2FbCQdvl4%3D (Accessed 28
January 2020).)
Stainless steel material decreases the probability of China, South Africa, Vietnam, the United States, Brazil,
uniform corrosion formation in a geothermal fluid envi- India, Mozambique, Madagascar, Norway, Ukraine, Kenya,
ronment. AISI 400 series stainless steels contain 12%–18% Kazakhstan, Indonesia, Malaysia, and Sri Lanka are the main
chrome, which is more suitable for turbine blades. AISI countries for titanium production [21].
430 (Ferrite) and AISI 431 (Martensitic) stainless steels are Inconel, a nickel (Ni) alloy, is another important
often used for valve and pump components in geothermal material for turbine manufacturing. There are various types
systems. Stainless steel production is widespread throughout of Inconel available on the market, and the mineral content
the world (Fig. 2.6). Based on the World Steel Dynamics defines the strength and corrosion resistance (Table 2.1).
2015 data, China, Japan, and the United States are the top For high-temperature geothermal systems, it is suitable to
three countries in stainless steel production [19]. use nickel, chromium, and molybdenum (Ni-Cr-Mo) alloys
Titanium (Ti) and titanium alloys are more resistant to as a material (Kaya and Hoşhan, 2005). Inconel-625 and
corrosion. In addition, titanium is resistant to cavitation Hastelloy C-256 are especially strong in combatting cor-
and impact damage. Ti alloys are much more resistant to local rosion. Other nickel alloys that have iron elements can
corrosion than pure titanium. Ti-code-7 (Ti-0.15 Pd), Ti also be used in some applications [20]. These alloys are
code-12 (Ti-0.3 Mo-0.8 Ni), and Ti-code-29 (Ti-6 Al-4 V- much stronger than stainless steel. Forged Inconel is mostly
0.1 Ru) show good corrosion resistance [20] when they are used for turbine shafts because of its strength against
compared based on cost and performance. The critical places rotational force.
for using titanium alloys can be impellers, wellhead valves,
pressure gauges, pipes, and blow-out preventers.
The world’s titanium production is limited to certain 2.2.1.3 Machine inventory and factory model
areas (Fig. 2.7). Based on data from the US Geological The factory model includes the minimum workspace
Survey (USGS) Minerals Yearbook 2015, Canada, Australia, required for the machines in addition to machine-related
FIG. 2.7 World titanium ore production, units are thousand metric tons per year. (Data Source: USGS. Minerals yearbook—Metals and minerals.
United States Geological Survey; 2015. Available from: https://www.usgs.gov/centers/nmic/minerals-yearbook-metals-and-minerals (Accessed 22
January 2020).)
TABLE 2.1 Inconel alloy element compositions by weight.

Elements by mass (%)
Inconel Nickel Chromium Iron Molybdenum Niobium Cobalt Magnesium Copper Aluminum Titanium
alloys (Ni) (Cr) (Fe) (Mo) (Nb) (Co) (Mn) (Cu) (Al) (Ti) Others
600 72.00 16.00 10.00 0.00 0.00 0.00 1.00 0.50 0.00 0.00 0.50
617 44.00 24.00 3.00 10.00 0.00 15.00 0.50 0.50 1.00 0.50 0.50
625 58.00 20.00 5.00 10.00 4.00 1.00 0.50 0.00 0.40 0.40 0.70
690 60.00 30.00 9.00 0.00 0.00 0.00 0.35 0.01 0.02 0.00 0.62
718 55.00 21.00 12.00 3.00 5.00 1.00 0.30 1.00 1.00 0.20 0.50
X-750 70.00 14.00 9.00 0.00 1.00 1.00 1.00 0.50 0.50 2.50 0.50
labor requirements. The machine inventory includes heavy of 3400 MAWH. The machining rate for each machine is
machining and precise computer numerical control (CNC) based on the MAWH and operation hours with and without
machining processes [22] (Table 2.2). Heavy machining set-up time for the factory model. In a dedicated factory
includes electric arc furnace casting and forging operations. model, machines are utilized as much as possible across
CNC machining includes a five-axis CNC machine, a three- several different projects to fulfill the MAWH because
axis CNC machine, a CNC horizontal lathe, and a CNC the capital cost associated with the facilities and equipment
grinding machine. The quality control (QC) pieces are a is applied over the total time of MAWH. However, in a
coordinate measuring machine (CMM) and overspeed shared factory model, the capital cost associated with
testing and dynamic balancing (OSTB). The proposed buildings, facilities, space, and the depreciation of machines
manufacturing model has not only been tested for geo- is proportionally distributed over the time when the machine
thermal turbines, but has also been validated against other is utilized for manufacturing the specific turbine parts. The
industries such as solar PV [23, 24]. amount of required machinery is selected based on total
One other important parameter in a factory model is the operational hours for different volumes of manufacturing
annual maximum allowable working hours (MAWH). and MAWH. With up to 100 units per year of manufacturing
MAWH can be defined by the annual total labor hours volume, one of each machine would be enough to fulfill
and number of shifts as well as production-up times. As the target manufacturing volume. For more than 100 units
an example, 250 annual labor days and 8 working hours with per year, additional machines would be required
2 shifts per day with 85% production-up time, make a total (Table 2.3). The manufacturing volume of 50 units per year
calculated based on the average power consumption of each

TABLE 2.2 Machine inventory for the custom machine, operating for a given number of operational hours.
factory model. The storage and shipping costs of the turbine parts/compo-
Energy nents are not included in the factory model.
Footprint consumption
Machine type Price ($) (m2) (kW)
2.2.1.4 Machining cost analysis
Five axis CNC $150–$300 k 10–15 20–30
The machining costs of the key components of turboex-
machine
panders, including impellers and shafts, are calculated by
Three axis $100–$200 k 10–15 20–30 using design for manufacture and assembly (DFMA)
CNC machine
software. DFMA allows the user to produce a detailed pro-
CNC $60–$150 k 12–18 30–40 jected cost of the component based on the volume of
horizontal material needed, the machines and process steps, the
lathe
machine setup time, and tooling if needed [25]. Fig. 2.9
CNC grinding $80–$150 k 35–40 10–20 shows the representative material and machining cost esti-
machine mates of a typical impeller for both a custom design and
Casting $500 k–$1 M 1000 500 a standard design (at a volume of 10 units per year)
Forging $400–$500 k 1000 500
5 MWe turboexpander. Tooling investment considers tool
wear and lifetime, and it is calculated as an additional cost
Over speed $10–$20 k 10 5–7 element for processes that require part-specific dies and
testing and
balancing
tools. A custom design 5 MWe impeller could be
machine $4000/unit, compared to $1000/unit with the standard
(OSTB) design (Fig. 2.8). Assuming the same yield rate, the standard
CMM $8–$10 k 10 1–3
design impellers can lead to a cost savings of between 25%
dimensioning and 30% compared to a custom design (single unit) because
of the set-up times for machining the impeller. A similar
Assembly line $50–$300 k 50–60 5–10
approach is applied to other subcomponents of a turboex-
Data Source: NREL Industry outreach. pander such as shafts, nozzles, inlet guide lanes, disks,
and casings to calculate machining costs.
can be set as a threshold based on manufacturers’ annual

manufacturing capacities and project portfolio. Annual
2.3 Definition of minimum sustainable price
straight-line depreciation is selected for capital costs asso- The minimum sustainable price (MSP) is the minimum
ciated with machinery, as is handled in accounting proce- price that a company would have to charge for a good or
dures. Facility cost is defined based on the minimum service to cover all variable and fixed costs and make
required working area for each machine. Energy cost is enough profit to repay investors at their minimum required
TABLE 2.3 Number of required machines for different volumes of manufacturing at MAWH.
CNC
Five axis CNC Three axis CNC horizontal CNC grinding Assembly
#Units machine machine lathe machine CMM OSTB line
10 1 1 1 1 1 1 1
25 1 1 1 1 1 1 1
50 1 1 1 1 1 1 1
100 1 1 1 1 1 1 1
150 1 2 1 1 1 1 1
200 1 2 1 2 1 1 1
500 2 5 3 4 1 1 2
1000 3 9 5 7 1 2 3
Raw Material Purchased MaterialEstimated Volume Material Estimated Material Cost

Part Material Procurement Unit Price ($/kg)Unit Price ($/kg) (m3) Density (kg/m3) Weight (kg) ($)
Impeller Titanium Plate 22.82 39.04 0.037 4,500 167 6,500
Process Machine Manufacturing

Setup Machining Center Hole Drilling
Subtotal Cost/Unit
Part Machining Process Time/Unit Time/Unit Rate/Unit
Cost/Unit ($) ($)
(hours) (hours) ($/hour)
1 Unit (Custom Design)
Drilling 0.8 0.2 35 35 Blade Roughing
Highly flexible simultaneous
5-Axis CNC Roughing 25.0 5.0 35 1,055 5-axis roughing
5-Axis CNC Rest Milling 42.0 8.0 35 1,760

Impeller 4,000
5-Axis CNC Finishing 10.0 2.0 35 422
Hub Finishing
QC 2.5 0.5 27 80 Optimized tool paths for
finishing hubs
Balancing 20.0 4.0 25 648
10 Units (Standard Design)
Drilling 0.3 0.2 35 9 Rest Milling

Automate removal of
5-Axis CNC Roughing 2.5 5.0 35 264 remaining material
5-Axis CNC Rest Milling 4.2 8.0 35 440

Impeller 1,000
5-Axis CNC Finishing 1.0 2.0 35 105
Blade / Splitter Finishing
QC 0.3 0.5 27 20 Automate finishing of
blades and splitters
Balancing 2.0 4.0 25 162
FIG. 2.8 Representative material and machining cost estimates of a typical impeller for both a custom design and a standard design (at a volume of 10 units per
year) 5 MWe turboexpander.
rates of return [24]. The MSP is computed by setting the net 2.4 Manufacturing analysis case studies
present value (NPV) of an investment equal to zero with the
internal rate of return (IRR) equal to the weighted average The manufacturing cost and MSP for three different scenarios
cost of capital (WACC). The US capital assets pricing are calculated for three case studies, where each scenario had
model is used to derive these debt and equity ratios, and five volumes of manufacturing (1, 5, 10, 25, and 50):
to weight them by their relative contribution to the overall (1) 1 MWe ORC turboexpander.
capital structure of the firm to estimate WACC values [26]. (2) 5 MWe ORC turboexpander.
The purpose of the discounted cash flow (DCF) is to (3) 20 MWe steam turbine.
create a detailed financial model to provide the necessary
framework for deriving the MSP for each product in a All three scenarios assume US production facilities and
manufacturing facility. Within the DCF, there can be costs. The generator is a separate piece and is not included
several considerations for manufacturing, such as capital in the manufacturing cost analysis. Increasing volumes of
costs, fixed operating costs (labor, depreciation, inflation, manufacturing effectively decreased the manufactured cost
taxes, insurance, and rent), typical sales, general and admin- per unit, as we spread the capital expenditures (CAPEX)
istrative (SG&A) expenses, typical design and engineering over more units. Machine set-up times and D&E costs are
(D&E) costs, and warranty coverage [24]. DCF model uses the cost components that are most impacted by volume
a simple straight-line depreciation for expenditures such as manufacturing, as these are essentially one-time charges
equipment and facilities, and the discount rate is calculated that are not volume-dependent.
from the required rate of return (ROR). A summary of the In Case 1, the results show that MSP decreases signifi-
financial input parameters required for DCF analysis can cantly when the volume of manufacturing is increased from
be found in Table 2.4. The MSP is derived by an iterative 1 unit (custom design) to 5 units (standard design). The MSP
algorithm that runs until the NPV of the cash flow equals of a single custom design 1 MWe turboexpander is found to
the total initial capital expenditure. be 893 $/kW, whereas a standard design 1 MWe
turboexpander has an MSP of 226 $/kW at a manufacturing

TABLE 2.4 Summary of input parameters for DCF analysis. volume of five (Fig. 2.9). Effectively, a standard turboex-
Inputs for DCF calculations Values Units pander design, even at low manufactured volumes, could
save approximately 75% of the turboexpander $/kW.
Inflation on cost of goods sold 3 %
In Case 2, the results show that MSP decreases signifi-
(COGS)
cantly when the volume of manufacturing is increased from
Corporate interest rate 3.3 % 1 unit (custom design) to 5 units (standard design). The MSP
Initial loan (or bond) maturity 10 Years of a single custom design 5 MWe turboexpander was found
to be 216 $/kW, whereas a standard design 1 MWe turboex-
Corporate tax rate 30 %
pander has an MSP of 66 $/kW at a manufacturing volume
Dividend payout rate 0 % of five (Fig. 2.10).
Cost of equity 10.6 % In Case 3, a manufacturing volume of up to 5 units per
year is selected based on the annual demand for geothermal
Cash flow analysis period 20 Years
steam turbines and the manufacturing capacities. The MSP
Working capital collection 10 Years of a single custom design 20 MWe geothermal steam turbine
period
is found to be 361 $/kW, whereas the MSP of a standard
Calculated WACC 5.3 % design 20 MWe steam turbine is calculated as 135 $/kW
Working capital inventory 4 Years at an annual production rate of 5 units per year
turnover (Fig. 2.11). Effectively, a standard steam turbine design,
even at low manufactured volumes, could save approxi-
Working capital payable period 10 Years
mately 63% of the steam turbine $/kW.
CAPEX Initial target capital 64 % A comparison of the MSP analysis for all three cases can
structure (% of debt)
be found in Table 2.5. The manufacturing cost of a custom
Replacement equip. target 50 % design 5 MW ORC turboexpander is only $187,000 more
capital structure than that of a custom design 1 MW ORC turboexpander.
Depreciable life for plant 25 Years This shows that the size of the turbine does not have a sig-
nificant effect on the total cost of the turbine/turboexpander.
Capital replacement loan 10 Years
maturity However, if the unit costs per MW for both custom and
standard design cases are considered, the manufacturing
Equipment depreciation type 7 years N/A
cost savings are significant (667 $/kW for a 1 MW turboex-
straight-line
pander and 150 $/kW for a 5 MW turboexpander).
Tooling depreciation type 3 years N/A
straight-line
Building depreciation type 15 years N/A
2.4.1 Sensitivity analysis
straight-line Sensitivity analysis determines how the target manufacturing
cost model is affected based on changes in cost factor
FIG. 2.9 Calculated MSP and manufacturing cost breakdown for a 1 MWe ORC turboexpander in different volumes of manufacturing in the
United States.
FIG. 2.10 Calculated MSP and manufacturing cost breakdown for a 5 MWe ORC turboexpander in different volumes of manufacturing in the
United States.
FIG. 2.11 Calculated MSP and manufacturing cost breakdown for a 20 MWe geothermal steam turbine in different volumes of manufacturing in the
United States.
TABLE 2.5 Comparison of MSPs for standard and custom design turbines.
Custom design Standard design Standard design
MSP Single unit Volume of 5 units Volume of 50 units
1 MW turboexpander $893,000 893 $/kW 226,000 $ 226 $/kW $74,000 74 $/kW
5 MW turboexpander $1,080,000 216 $/kW 332,000 $ 66 $/kW $152,000 30 $/kW
20 MW steam turbine $6,350,000 361 $/kW 2,790,000 $ 135 $/kW N/A N/A
variables (input variables). The impact of each input on the thus have proportional effects relative to the weight on the
calculated MSP can be calculated by varying one input var- manufactured cost. For the sensitivity analysis, a custom
iable while keeping the others constant. Each cost factor in design single unit 5-MWe ORC turboexpander and a custom
the overall cost model has a different weight based on the rel- design single unit 20-MWe steam turbine were evaluated
ative importance, and a change in one input variable would with respect to their standard design higher manufacturing
volume alternatives. The manufacturing volume is set at This makes the manufacturing labor the second most
10 units per year for the ORC turboexpander and 5 units important cost factor in a custom design unit. Other
per year for the steam turbine. important cost factors are sales and general administration
The D&E time for a custom design 5 MWe ORC tur- (SG&A), equipment cost, energy cost, and material cost.
boexpander is assumed to take 9 months of labor from Their effect is less important on manufacturing costs for a
two full-time employees (FTEs). Thus, D&E is the most custom design unit. However, when the manufacturing
important cost factor for a custom design unit due to the time model has changed to a standard design at a volume of
spent on a tailor-made design for each custom unit 10 units year, the material and the labor costs become the
(Fig. 2.12). Custom design turbine manufacturing has a dominant cost factors with shares of 46% and 31%, respec-
longer set-up time with respect to high volume standard tively. On the other hand, D&E and SG&A costs become
design turbines. The machining set-up time constitutes less important. The cost drops by the cost factor are also
51% of the total machining cost for a custom design unit. presented on cost waterfall charts (Fig. 2.13).
Design & Engineering
Labor
Selling, General & Administration
Materials
Capital
Energy
Outsourced Parts
Maintenance
–50000 –40000 –30000 –20000 –10000 0 10000 20000 30000 40000 50000
Selling, General & Design &

Maintenance Outsourced Parts Energy Capital Materials Labor
Administration Engineering
25.00% $221 $1,288 $3,545 $11,602 $11,743 $16,646 $29,394 $39,658
–25.00% –$221 –$1,288 –$3,545 –$11,602 –$11,743 –$16,646 –$9,394 –$39,658
Design & Engineering
Labor
Selling, General & Administration
Materials
Capital
Energy
Outsourced Parts
Maintenance
–50000 –40000 –30000 –20000 –10000 0 10000 20000 30000 40000 50000
Selling, General & Design &

Maintenance Outsourced Parts Energy Capital Materials Labor
Administration Engineering
25.00% $55 $1,213 $1,358 $2,900 $11,061 $1,665 $7,348 $3,966
–25.00% –$55 –$1,213 –$1,358 –$2,900 –$11,061 –$1,665 –$7,348 –$3,966
FIG. 2.12 Sensitivity analysis for 5 MWe turboexpander based on (A) Manufacturing volume of 1 unit per year (custom design) and (B) Manufacturing
volume of 10 units per year (standard design) in the United States.
FIG. 2.13 Manufacturing cost drop by cost factor for a standard design (10 units) 5 MWe ORC turboexpander.
The custom design 20 MWe steam turbine manufacturing The balance of plant (BOP) is optimized to maximize power
has high labor requirements during assembly. This makes generation. In other words, the BOP, including the heat
labor cost the most important cost factor for a custom design exchanger, the air-cooled condenser, pumps, and piping,
unit (Fig. 2.14). Labor includes set-up time, which is 49% of can be designed to optimize turbine output. The design
the total machining cost for a custom design single unit. assumptions for the optimized system include the pinch
Capital cost, including the equipment and facilities cost, is point temperature.
the second most important cost factor. D&E time for a The design point is set at 175°C for the inlet brine tem-
custom design 20MWe steam turbine is assumed to take perature and 80 kg/s for the brine mass flow rate for the
12months and four FTEs due to time spent on tailor-made standard turbine. An optimization algorithm is developed
parts for each unit. The design of steam turbines is more to optimize BOP and operating conditions by adjusting
detailed than ORC turboexpanders because they are in direct the pressure before and after the turbine for maximum
contact with saturated steam as well as noncondensable gases turbine output at given geothermal inputs. The performance
(NCG) such as H2S and CO2, and they have multiple pressure of the standard turbine is compared to a custom design
stages. SG&A, capital (equipment and facilities), and mate- turbine by running off-design models for varying geothermal
rials are the other important factors that have a moderate resource temperatures (between 160°C and 190°C) and brine
effect on the manufacturing cost for a custom design unit. flow rates (between 40 and 120 kg/s). A turbine off-design
For one-off design turbines at a volume of 5 units, while efficiency curve provided by a reliable manufacturer as a
the impact factor of labor and material stays almost the same, function of the mass flow rate of the working fluid is used
the D&E and SG&A costs becomes less important. The cost to evaluate the impact on power generation of the standard
drops by the cost factor are also presented on cost waterfall versus custom design (Fig. 2.17). The design point isentropic
charts (Fig. 2.15). efficiency is selected as 80%. The turbine efficiency curve
shows relative efficiency as a function of relative working
fluid mass flow rate at a constant isentropic enthalpy drop
2.5 Power plant design and performance across the turbine. The curve does not account for changes
in isentropic enthalpy drop. In IPSEpro modeling, both the
analysis
working fluid mass flow rate and the isentropic enthalpy drop
The purpose of the turbine performance analysis is to across the turbine vary. However, the turbine model only con-
determine the commercially favorable operating range of siders the working fluid mass flow rate when adjusting the
a standard ORC compared to custom designed ORC turbine isentropic efficiency. The resulting efficiency curve
equipment. A typical example of the process flow model is likely not representative of actual turbine performance
for an ORC geothermal power plant at a given design point and is used only for illustrative purposes in this report.
of a standard size (5 MWe) turbine can be seen in Fig. 2.16. Turbine manufacturers and project developers have access
FIG. 2.14 Sensitivity analysis for 20 MWe turboexpander based on (A) manufacturing volume of 1 unit per year (custom design) and (B) manufacturing
volume of 5 units per year (standard design) in the United States.
FIG. 2.15 Manufacturing cost drop by cost factor for a standard design (5 units) 20 MWe steam turbine.
GTO CEMAC ORC

Basic Organic Rankine Cycle
Cycle Characteristics
Turbine Enthalpy Drop 4706.83 [kW]
70.35 478.51 Cycle El. Power Output 4520.44 [kW]
5 70.35 478.51
7.721 112.18 1 Net El. Power Output 3750.55 [kW]
7.521 111.79
Total heat Input 34655.48 [kW]
80 741.73 Gross Cycle Efficiency 13.04 %
20 175
Net Cycle Efficiency 12.70 %
Condenser Duty 30051.18 [kW]
70.35 198.74
Turbine Pressure Ratio 9.21 [-]
7.821 112.8 70.35 411.6
2 Turbine Mass Flow 70.35 [kg/s]
0.817 65.306
70.35 198.74 Turbine Inlet Volumetric Flow 3411.57 [I/s]
80 495.71
7.821 112.8 Turbine Outlet Volumetric Flow 32726.19 [I/s]
19.9 117.8
12
80 308.54 3066 25.157
19.8 73.326 1.013 24.899
4
11 70.35 -15.559
3
70.35 -14.101 0.807 29.455
7.921 29.827
-625.5 3066 15.152
1.013 15
# p t h x fluid
[bar abs] [°C] [kJ/kg] [-]
1 7.52 111.79 478.51 1.00 n-Pentane
2 0.82 65.31 411.60 1.01 n-Pentane ORC Fluid Geothermal Brine Air
3 0.81 29.45 -15.56 0 n-Pentane
mass[kg/s] h[kJ/kg] mass[kg/s] h[kJ/kg] mass[kg/s] z[kg/kg]
4 7.92 29.83 -14.10 0 n-Pentane
p[bar] t[°C] p[bar] t[°C] p[bar] t[°C]
5 7.72 112.18 478.51 1.18 n-Pentane
11 1.01 15.00 15.15 0 Cooling Water
12 1.01 24.90 25.16 0 Cooling Water
FIG. 2.16 Process flow diagram of standard-size ORC power plant [27].
FIG. 2.17 Off-design turbine efficiency curve.

FIG. 2.18 Actual plant brine effectiveness.
to actual turbine performance curves and can use the method- design turbines using results from IPSEpro over the range
ology in this report to assess the potential benefits of standard of geothermal resource temperatures and flow rates of
turbine design. interest. The base case inputs for the geothermal resource
One other important parameter in the plant performance are applied to SAM inputs and a base case model is estab-
analysis is the brine effectiveness (BE). Simply, BE is the lished (Table 2.6).
amount of energy that you can extract per pound of geo- To compare the projects and results on a common basis,
thermal brine or steam, which is defined as net plant output the “exact number of wells” option is chosen in SAM, and
divided by the brine flow rate (w-h/lb). The use of BE to the number of production wells is set at one. For the base
describe plant performance comes from the Geothermal case, this results in a gross turbine output power capacity
Technology Evaluation Model (GETEM, 2016) on which (nameplate capacity) of 5 MW, so that the power plant
the System Advisor Model (SAM) geothermal module cost values from the MSP analysis can be used.
is based. SAM allows the user to set plant efficiency (%), which
In SAM, BE is set by adjusting the plant efficiency input. sets the plant BE as a percentage of the maximum brine
According to IPSEpro modeling results, the BE of binary effectiveness [28]. Setting the plant efficiency to 100%
plants studied varies between 3.3 and 7.5 w-h/lb gives a plant with BE equal to the maximum brine effec-
(Fig. 2.18). This value is 5.9 w-h/lb for the standard turbine tiveness. Setting the plant efficiency to 50% provides a plant
at its design point in IPSEpro. The BE value determines the with brine effectiveness equal to 50% of the maximum BE.
more conventional thermal to electric conversion efficiency Using these data, a reverse calculation of the plant effi-
(TE) of the plant. TE varies as a function of inlet geothermal ciency is needed to match BE values from IPSEpro runs.
brine temperature and mass flow rate (Fig. 2.19). TE is cal- The binary plant efficiency is set to 65.1% to match the
culated as 10.83% at the design point for the base case IPSEpro BE results in w-h/lb for the base case.
IPSEpro model. The system cost scenarios are developed for custom
design and standard design turbines. The SAM version of
GETEM does not currently include the ability to automati-
2.6 Economic analysis
cally estimate plant costs, but the Excel version of GETEM
Monetizing the processes developed in power plant perfor- does. Therefore, GETEM is used to estimate the plant costs
mance modeling helps project developers to convert perfor- and those values are imported in SAM. For the custom
mance calculations into a representative technoeconomic design scenarios, the plant size and efficiency results from
model of a total geothermal power plant. NREL’s SAM is the IPSEpro model are used as inputs to GETEM to estimate
used to perform a DCF analysis of standard and custom the plant costs. Plant costs in GETEM are determined by
FIG. 2.19 Thermal to electric conversion efficiency for 5 MWe ORC turbine.
TABLE 2.6 Base case geothermal resource TABLE 2.7 Financial parameters for SAM model.
characterization for SAM financial model.
Parameter Unit Value
Parameter Unit Value PPA price /kWh 10.00
Resource temperature °C 175
Annual escalation rate % 1.00
Reservoir pressure change per 1000 lb psi-h 0.35
IRR target Years 20.00
Reservoir depth m 2000 Project debt ratio % 60.00
Temperature decline rate %/year 0.3 Real discount rate %/ 5.5
Number of production wells – 1 year
Production well flow rate kg/s 80 Inflation rate % 2.5
Number of injection wells – 1 Nominal discount rate %/ 8.15

year
Annual interest rate % 7.00
Incentives (PTC/ITC) $ 0.00
Depreciation structure (5 years % 100.00
MACRS)
estimating the individual costs for the major plant compo-
nents (turbine, heat exchangers, condenser, and working
fluid pump) and using a direct-cost multiplier to account
for the piping, instrumentation, construction costs, etc. This
value is then used as the input for the specified plant cost in For the DCF analysis, a business model is developed
SAM. For the standard design scenarios, the same indi- with standard financial assumptions for all scenarios
vidual component costs and direct cost multiplier are used, (Table 2.7). Changes in financial parameters would affect
but the turbine cost is decreased by $150/kW to reflect the the NPV of costs. The simplest business model is a 100%
cost savings from using a standard turbine design (see equity model in which the developer pays cash for the
Table 2.5). Results from IPSEpro are used as the BE (plant project at the start of operations. In this case, the standard
efficiency) inputs in SAM for the custom and standard sce- turbine is not as competitive as a custom turbine. Realisti-
narios to account for the reduced efficiency of the standard cally, the more you defer costs to the future (debt) or offset
turbine (compared to the custom turbine) when it operates at costs in the future (depreciation, tax advantages), the more
off-design conditions. the custom turbine design is favored.
2.6.1 Decision criteria used in SAM and debt-related costs. Real discount rate is a measure of
financial model the time value of money expressed as an annual percentage.
SAM’s financial model results are very sensitive to the real
The decision criteria of the SAM financial model are func- discount rate input [29, 30]. The NPV is calculated as:
tions of: X n Fn
l Electricity generated. NPV ð$Þ ¼ 1 ð1 + d Þn
l Power purchase agreement (PPA) price.
l Analysis period/project life. where
l Project equity investment amount. l Net cash flow in year n, $ (Fn).
l Annual project costs. l Annual discount rate (d).
l Discount rate.
The simplified LCOE calculation uses the user-defined
The power purchase agreement (PPA) price is the bid price installation cost, operating costs, and a fixed charge rate
that the project receives for each unit of electricity that the as input, and the model calculates the LCOE based on the
system generates. Levelized PPA uses the discount rate to annual energy generated by the system. The calculator
determine the present value of the project’s PPA revenue can also calculate the fixed charge rate when users provide
over its lifetime. For PPA models, SAM assumes the project basic financial parameters. The list of financial parameters
sells all the electricity generated by the system at a price required to calculate financial outputs can be found in
negotiated through a PPA. A financially viable project is Table 2.8. The LCOE is calculated as:
likely to have a levelized cost of electricity (LCOE) that
Ccap + FOC
is less than the levelized PPA price to cover project costs Xn ðAEP er Þ + VOC
and meet IRR requirements. If there is no profit margin $
LCOE ¼
between the price of supply (PPA price) and the cost of pro- kWh 1 ð1 + r Þn
duction (LCOE), a project will be financially unviable.
where
The IRR is a measure of the project’s profitability and is
defined as the nominal discount rate that corresponds to an l Project lifetime, years (n).
NPV of zero [29, 30]. SAM uses a search algorithm to find l Capital cost, $ (Ccap).
the PPA price required to meet the target IRR and reports l Fixed annual operating cost, $ (FOC).
NPVs for the project. l Variable operating cost, $/kWh (VOC).
The NPV is the net present value of the after-tax cash l Nominal discount rate (r).
flow discounted to year one using the nominal discount l Annual electricity production, kWh (AEP).
rate. The PPA price determines annual revenue. The net
capitalized cost is the sum of the total installed cost and
debt, other financing fees, and reserve funding from the
2.6.2 SAM results and discussion
financial parameters, less investment-based and capacity- To start with, SAM scenarios are created for custom design
based incentives. SAM also allows users to specify param- and standard design turbines for the base case (175°C tem-
eters such as up to five construction loans to approximate perature and 80 kg/s mass flow rate), where it is assumed
interest during construction (IDC) that SAM considers a that the standard and custom turbine designs have identical
cost to the project. The project term debt input variables performance. The net electricity generation capacity is used
determine the size of the debt or the amount borrowed to calculate annual revenue from electricity sales. The
TABLE 2.8 Summary of financial parameters used to calculate financial outputs.

PPA Discount Project Electricity IRR target Analysis
(revenue) rate costs Expenditures generation year period
IRR X X X X
NPV X X X X X
LCOE X X X X X X
Levelized X X X X
PPA
l Standard turbines are more cost-effective than custom

TABLE 2.9 Comparison of SAM financial model results turbines near the design point and less cost-effective
for custom and standard design scenarios. away from it. This is because the standard turbine cannot
Custom Standard perform at a higher isentropic efficiency than the custom
design design turbine; it can only be equal or less.
Metric Unit (base case) (base case) l The NPV differences between standard and custom
design scenarios show 45 of 63 test cases that resulted
Levelized COE ¢/kWh 10.49 9.82
(nominal)
in positive values where standard design turbines are
favorable (Fig. 2.22).
Levelized COE ¢/kWh 8.13 7.61
(real) Using a standard turbine design results in an NPV that is
Net present $ $1,346,430 $2.786.840
higher than when using a custom turbine design over a large
value (NPV) range of geothermal brine temperatures and flow rates, as
shown in Fig. 2.22. The highest NPV results tend to be at
Internal rate of % 7.20% 11.99%
return (IRR)
elevated geothermal brine temperatures and flow rates.
The figure does not consider practical limitations on the
Year IRR is Year 20 20 power output from the standard turbine. The actual output
achieved
from the model can be much larger than the design output
IRR at the end % 10.03% 13.66% of 5000 kW, as shown in Fig. 2.23. In practice, a turbine
of the project would be unable to operate at this high an output above
Net capital $ $24,456,800 $22,144,500 its design point. The cut-off output for the standard design
cost (NCC) would change based on the technical specifications of dif-
Equity $ $9,782,720 $8,857,800 ferent turbine designs, but a large portion of the upper right
part of Fig. 2.22 is not in the practical operating range of the
Size of debt $ $14,674,080 $13,286,700
standard turbine design. Turbine manufacturers and project
NCC $ +$2,312,300 developers should keep these limitations in mind when eval-
difference uating this chart.
NPV difference $ +$1,440,410
2.6.2.1 Sensitivity analysis
As described in Section 2.5, a full turbine performance
curve is needed for detailed analysis. Therefore, the results
above are only illustrative of the relative costs and perfor-
results show that the standard design turbines provide
mance of standard and custom turbine designs. Although
savings at the net capital cost and result in a higher NPV
the data are inadequate to accurately model off-design
and IRR for the project at the given base case conditions
turbine performance, they give the information needed to
(Table 2.9). While the net capital cost saving may reach
determine the relative efficiency at which a standard turbine
+$2,312,300, the difference between the NPV of standard
design is cost-competitive with a custom turbine design.
design and custom design turbines could reach +$1,440,410.
The sensitivity analysis is conducted based on the impact
Then, the financial analysis is conducted over 63 off-
of turbine performance on the NPV of the power plant by
design cases by changing the inlet geothermal brine temper-
iteratively varying geothermal brine temperature and flow
ature (between 160°C and 190°C) and the inlet mass flow
rate to calculate the isentropic turbine efficiency at the
rate (between 40 and 120 kg/s). The standard turbine power
break-even NPV point (Fig. 2.23). In other words, the
generation capacity is taken as 5 MW with off-design power
relative isentropic efficiency of the turbine is set to
outputs ranging between 1.4 and 6.9 MW gross. The results
achieve the NPV of the custom plant equal to the NPV
for standard turbines operating at off-design conditions
of the plant with a standard turbine. This is the economic
show that:
boundary between the standard design and custom design
l Net capital cost in $/kW significantly decreases with turbines.
respect to increasing geothermal brine temperature For the sensitivity analysis, 63 test case scenarios are
and mass flow rate (Fig. 2.20). taken, and 1008 observation points are generated for dif-
l The standard turbines are competitive over a wide range ferent relative isentropic efficiencies with respect to the
of temperatures and flow rates, and they give positive design point ranging between 85% and 100%. The results
NPV for cases near the design point (Fig. 2.21). (Areas for select cases (minimum, design, and maximum geo-
at the right side of the economic boundary curve rep- thermal brine temperature and flow rates) are shown in
resent positive NPV.) Fig. 2.24 and for all cases in Fig. 2.25. In these figures,
FIG. 2.20 Net capital cost per kilowatts for different off-design cases of the standard turbine.
FIG. 2.21 NPV after tax for different off-design cases of the standard turbine.
FIG. 2.22 NPV difference between custom and standard design scenarios for given resource conditions. The black solid line represents the economic
boundary of standard turbines where the NPV difference is zero.Areas at the right side of the economic boundary curve represent positive NPV cases where
standard design turbines are favorable.
FIG. 2.23 Standard turbine design gross turbine output in kilowatts as a function of geothermal brine temperature and flow rate. Standard turbine design
output (nameplate capacity) is 5000 kW.
FIG. 2.24 Sensitivity analysis for NPV difference with respect to relative isentropic efficiencies for select cases.
FIG. 2.25 Sensitivity analysis for NPV difference with respect to relative isentropic efficiencies for all cases. Gray dashed line, gray dotted line, and
black solid line represent the lower limit, median, and upper limit, respectively.
FIG. 2.26 The required isentropic efficiency of the standard turbine relative to a custom turbine to get a break-even NPV.
the standard turbine design is cost-competitive at a given custom turbine design for each case. The standard turbine
relative isentropic efficiency if the NPV difference cost is fixed for each case while the custom turbine cost
(standard design NPV minus custom design NPV) is depends on its size and efficiency. At low geothermal brine
positive. There is a large range of relative isentropic temperatures and flow rates, where the plant power output is
efficiencies over which the standard turbine design is lower, the plant cost for the custom turbine is lower than for
cost-competitive for the maximum and design geothermal the standard turbine because of the small turbine size. To
brine temperatures and flow rates (Fig. 2.24). For the lowest compensate, the standard turbine would have to operate at
geothermal brine flow rate and temperature, the standard higher efficiency and generate more electricity than the
design is not competitive, even at 100% relative efficiency. custom turbine to be cost-competitive. This illustrates that
The correlation between the NPV difference versus rel- at some point, building a smaller custom turbine at a higher
ative efficiency is linear (Fig. 2.26). By fitting a linear curve cost ($/kW) offsets the cost savings from a standard (but
to each case and calculating the relative efficiency where the oversized) turbine. This is the type of information a manu-
NPV is zero, the break-even isentropic efficiency is deter- facturer would need to consider when deciding which sizes
mined for each case, or the relative isentropic efficiency or design power generation capacities to choose for a series
of the standard turbine necessary to make the project of standard turbine designs.
cost-competitive with a custom turbine design.
The results of this analysis are shown in Fig. 2.26. The
2.7 Closing remarks
results show that the NPV of the project is sensitive to
turbine isentropic efficiency. The results also imply that a The current global geothermal turbine market is driven by
detailed turbine efficiency analysis is needed for more custom turbines that are designed specifically to fit a devel-
precise economic analysis, and this is done at the oper’s demand for plant efficiency and varying geologic
project level. conditions encountered at different geographies and geo-
Fig. 2.26 shows that for lower temperature and flow thermal systems. The global manufacturing and value chain
rates, a standard turbine requires an isentropic efficiency of geothermal turbines is dominated by a small number of
greater than zero to be cost-competitive. The reason for this players in the market and in certain geographic locations,
is illustrated in Fig. 2.27, which shows the total plant cost which are selected by the manufacturer’s country of origin
savings from using a standard turbine design versus a and their strategic decisions. Most of the time, the
FIG. 2.27 Plant cost savings (standard minus custom) as a function of geothermal brine temperature and flow rate.
manufacturing locations are not the same as the location of successfully operate their facilities like the presented
geothermal areas, which creates a high volume of trade flow manufacturing model, it could result in up to 60% in
between the country of the manufacturer and the country of manufacturing cost savings.
installation. In practice, a standard turbine design would likely
The results of MSP analysis show that standard design operate at off-design conditions, resulting in lower effi-
turbines can have significant cost savings with respect to ciencies, less electricity generation, and less revenue than
the custom design single unit. The MSP calculations and a custom turbine design. It is important to know whether
sensitivity analysis also show that MSP could highly vary and under what conditions the upfront capital cost savings
based on turbine size, standardization, and the volume of from a standard turbine design could offset future revenue
manufacturing, and the economy of scale applies both to losses. The trends show that standard turbine designs could
the size of the turbine and the number of units manufactured be competitive over a wide range of temperatures and flow
in a single run. Even though the standardization of turbines rates. A calculation of the standard turbine efficiencies at
makes a significant change in the upfront capital, some off-design conditions that give the same NPV as a project
degree of custom design components may still be required. using a custom turbine show that the range of off-design
As an example, geothermal steam turbines often require efficiencies supports this conclusion. Developing and
custom metals because the geothermal fluid is highly cor- using standard turbine designs may be an effective strategy
rosive and the level of corrosion changes by the nature of for lowering geothermal power project costs if a pipeline
geothermal reservoir conditions and fluid chemistry at dif- of turbines can be set. Ideally, these turbines would be
ferent geothermal sites. designed to be flexible and operate over a wide range of
Sensitivity analysis for manufacturing shows that the conditions with minimal efficiency decreases. The strategy
labor and D&E costs are the main cost factors for a requires that multiple turbines be built at once and then
custom-designed unit. Manufacturing costs decrease signif- warehoused until sold. A significant barrier to imple-
icantly with increasing manufacturing volume due to menting this strategy is the demand for these technologies
shorter set-up times and spreading the D&E cost among at high volumes. However, as the global geothermal
the total number of units manufactured per year. This market continues to grow, opportunities in new markets
creates an opportunity for turbine manufacturers to realize will continue to increase. The emerging geothermal
manufacturing cost savings due to labor and D&E by markets discussed in this chapter show that there may be
switching from custom to standard design at larger volumes. an opportunity for using standardized turbines to reduce
If manufacturers at all steps of the supply chain could plant capital costs.
Acknowledgments [16] MENR. Turkish Ministry of Energy and Natural Resources

Renewable Energy Law 2010; 2010.
This work was supported by the US Department of Energy (DOE), the [17] Ellis PFI, Conover MF. Materials selection guidelines for geothermal
Office of Energy Efficiency and Renewable Energy (EERE), Geo- energy utilization systems. Austin, TX: Radian Corp.; January 1981.
thermal Technologies Office (GTO) under Contract No. DE-AC36- https://doi.org/10.2172/6664808. DOE/RA/27026-1.
08-GO28308 with the National Renewable Energy Laboratory [18] Kaya T, Hoshan P. Corrosion and material selection for geothermal
(NREL). The authors wish to thank reviewers for their comments systems. In: Proceedings world geothermal congress 2005; 2005. p. 5.
and suggestions, including Doug Arent, Jill Engel-Cox, Margaret [19] Steel Dynamics. 2015 Annual report. Steel Dynamics Inc.; 2015.
Mann, Emily Newes, and Samantha Reese of NREL. The authors also Available from: https://s3.amazonaws.com/b2icontent.irpass.cc/
thank Billy Roberts of NREL for his help on mapping. All errors and 2197/165986.pdf?AWSAccessKeyId¼1Y51NDPSZK99KT3F8VG2&
omissions are the responsibility of the authors. Expires¼1580257699&Signature¼9zZjMvMMB3ob07MYrZq%2Fb
CQdvl4%3D. [Accessed 28 January 2020].
References [20] Yadav M, Misra A, Malhotra A, Kumar N. Design and analysis of a
high-pressure turbine blade in a jet engine using advanced materials.
[1] GEA. Annual U.S. & global geothermal power production report. Mater Today Proc 2019. https://doi.org/10.1016/j.matpr.2019.07.530.
Geothermal Energy Agency; 2016. [21] USGS. Minerals yearbook—Metals and minerals. United States Geo-
[2] Think GeoEnergy. The Top 10 Geothermal Countries 2019—based logical Survey; 2015. Available from: https://www.usgs.gov/centers/
on installed generation capacity (MWe). Think GeoEnergy - Geo- nmic/minerals-yearbook-metals-and-minerals. [Accessed 22 January
thermal Energy News 2020;(Jan. 27). http://www.thinkgeoenergy. 2020].
com/the-top-10-geothermal-countries-2019-based-on-installed-gener [22] Klocke F, et al. Turbomachinery component manufacture by
ation-capacity-mwe/. [Accessed 28 January 2020]. application of electrochemical, electro-physical and photonic
[3] Bertani R. Geothermal power generation in the world 2010–2014 processes. CIRP Ann 2014;63(2):703–26. https://doi.org/10.1016/
update report. Geothermics 2016;60:31–43. https://doi.org/10.1016/ j.cirp.2014.05.004.
j.geothermics.2015.11.003. [23] Horowitz KAW, Woodhouse M, Lee H, Smestad GP. A bottom-up
[4] BNEF. Geothermal market outlook report. Bloomberg New Energy cost analysis of a high concentration PV module. AIP Conf Proc
Finance; 2016. 2015;1679(1):100001. https://doi.org/10.1063/1.4931548.
[5] DiPippo R. Geothermal power plants: Principles, applications, case [24] Goodrich A, et al. A wafer-based monocrystalline silicon photovol-
studies and environmental impact. Butterworth-Heinemann; 2008. taics road map: utilizing known technology improvement opportu-
[6] Frost & Sullivan. Global gas and steam turbine markets: Conventional nities for further reductions in manufacturing costs. Sol Energy
thermal power expansion driven by emerging markets and rising Mater Sol Cells 2013;114:110–35. https://doi.org/10.1016/j.
natural gas availability. Frost & Sullivan; 2014. M96C-14. solmat.2013.01.030.
[7] BNEF. Q2 2013 geothermal market outlook report. Bloomberg [25] Dewhurst B. Inc. DFA: Product simplification and DFM: Concurrent
New Energy Finance; 2013. costing, http://www.dfma.com/software/index.html; 2016. [Accessed
[8] BNEF. H2 2014 geothermal market outlook report. Bloomberg 17 May 2017].
New Energy Finance; 2014. [26] Ross SA, Westerfield R, Jordan BD. Fundamentals of corporate
[9] BNEF. H1 2015 geothermal market outlook report. Bloomberg New finance. New York, NY: McGraw-Hill, Irwin; 2009.
Energy Finance; 2015. [27] SimTech. IPSEpro process simulation environment. In: IPSEpro User
[10] GEA. Annual U.S. & global geothermal power production report. Guide; 2014.
Geothermal Energy Agency; 2015. [28] GETEM. Geothermal electricity technology evaluation model.
[11] Tartiere T. World overview of the organic Rankine cycle technology, Energy.gov; 2016. https://www.energy.gov/eere/geothermal/
https://orc-world-map.org/index.html; 2016. [Accessed 22 January geothermal-electricity-technology-evaluation-model. [Accessed 22
2020]. January 2020].
[12] DOE. GeoVision: Harnessing the heat beneath our feet. Washington, [29] Mendelsohn M, Kreycik C, Bird L, Schwabe P, Cory K. Impact of
DC: U.S. Department of Energy; 2019. DOE/EE-1306. financial structure on the cost of solar energy. Golden, CO: National
[13] Wall A, Young K. Doubling geothermal generation capacity by 2020: Renewable Energy Lab (NREL); March 2012. NREL/TP-6A20-
A strategic analysis. Golden, CO: National Renewable Energy Lab 53086. Available from: https://www.nrel.gov/docs/fy12osti/53086.pdf.
(NREL); September 2018. NREL/TP-6A20-64925. Available from: [30] Short W, Packey DJ, Holt T. A manual for the economic evaluation of
https://www.nrel.gov/docs/fy16osti/64925.pdf. energy efficiency and renewable energy technologies. Golden, CO:
[14] Poernomo A, Satar S, Effendi P, Kusuma A, Azimudin T, Sudarwo S. National Renewable Energy Lab (NREL); March 1995. NREL/TP-
An overview of Indonesia geothermal development—Current status 462-5173. Available from: https://www.nrel.gov/docs/legosti/old/
and its challenges; 2015. p. 11. 5173.pdf.
[15] Enerji Atlasi. Country update for geothermal power plants in Turkey.
Enerji Atlası; 2019. https://www.enerjiatlasi.com/jeotermal/.
[Accessed 22 January 2020].
Chapter 3
CO2 emissions from geothermal power

plants and state-of-the-art technical
solutions for CO2 reinjection
Joseph Bonafin and Arianna Bonzanini
Turboden S.p.A., Brescia, Italy
3.1 Introduction concentration will be higher. In igneous rocks, the carbonate

fraction is small, and so is the CO2 concentration in the geo-
Among several chemical components, geothermal fluids thermal fluid. Sedimentary rocks may contain different per-
commonly contain different gases that may be found in centages of carbonates, and thus the CO2 concentration may
the liquid phase dissolved in the geothermal brine or in vary strongly. In some cases, CO2 and other gases are
the gaseous phase mixed with geothermal steam. The derived from magma bodies, which may be located under
natural presence of these gases affects the physical and ther- the geothermal reservoir; these magmatic intrusions can
modynamic properties of the geothermal fluids, mainly of release gases during the natural degassing process.
the geothermal steam. The knowledge of the gas concen- The CO2 dissolved in the brine can precipitate in car-
tration is a crucial parameter in the design of geothermal bonate or silicate minerals, and the CO2 mixed in the steam
power plants because it affects the energy conversion effi- can be vented through fumaroles. These two processes
ciency of the power plant. The contained gases are usually reduce the CO2 concentration in the geothermal fluids
carbon dioxide (CO2), hydrogen (H2), methane (CH4), and can be defined as CO2 sinks. The balance of the sources
hydrogen sulfide (H2S), and ammonia (NH3), but also small and sinks of CO2 determines the chemical composition of
fractions of other gases can be found at particular sites. the geothermal fluids, which may vary in time due to the dif-
These gases are referred to as noncondensable gases ferent contributions of sources and sinks in the chemical
(NCG) because they do not condensate at the same con- reactions.
dition as water vapor, but remain in the gaseous phase. The GHG emission is generally smaller if compared to
CO2 is the most abundant gas, typically more than 95%, traditional power plants, such as oil, gas, or coal-fired
so the exploitation of geothermal resources may lead to plants. However, the geothermal sector has expanded in
greenhouse gas (GHG) emissions. This is because NCGs recent years, and geothermal reservoirs with high NCG
are often released in the atmosphere after passing through content have been brought into use. The attention paid to
the power plant together with the geothermal fluid. Even GHG emissions has also put geothermal power plants in
if methane is generally present in smaller concentrations, the discussion to evaluate the environmental footprint of
usually a few percentage points compared to CO2, it is a the kWh produced by means of geothermal sources. Espe-
strong climate-changing gas and may give a nonnegligible cially, banks and financial institutions such as the World
contribution to the GHG emissions of a power plant. Bank are interested in the assessment of geothermal power
However, because the most common gas is CO2, the focus plant CO2 emissions to evaluate whether the investment
will be mainly on this component. can be considered environmentally friendly and if the
The chemical composition of the geothermal fluid is dic- investment can benefit from government incentives for
tated mainly by the composition of the host rocks of the geo- green energy. To demonstrate the interest on the topic,
thermal reservoir. These are the rocks in contact with the the World Bank encouraged, in the ESMAP Technical
water infiltrating the Earth’s crust, which dissolves the car- Report [1], estimating ex ante the CO2 emissions of geo-
bonates composing the rocks. One of the parameters that thermal projects under development as well as geothermal
influences the CO2 concentration of the geothermal fluid power plants that already exist.
is the type of host rock. If it contains a large fraction of car- Meanwhile, an ongoing debate has been opened to
bonate, as in the case of carbonate rocks, the CO2 clarify whether geothermal energy can be classified as
Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00012-3

Another random document with
no related content on Scribd:
invaluable to our rivals though not as yet in any way competent to exercise
independent authority.
[1] "East of Suez ... there lies upon the eyes and foreheads of all men a
law which is not found in the European Decalogue; and this law runs:
'Thou shalt honour and worship the man whom God shall set above thee
for thy king; if he cherish thee thou shalt love him; and if he plunder and
oppress thee thou shalt still love him, for thou art his slave and his
chattel.'" Imperial Rule in India (Page 43). Theodore Morison.
There must come a time when the people of every habitable part of the
world will have tried the system of government by majority of elected
representatives. Even in the case of a nation like China, which has at
present no desire among its proportionally small class of educated minds for
such a form of rule, the popular longing for enfranchisement will arise, and
sooner or later a representative form of government will be established. The
obviously possible oppression and tyranny of democratic rule are dangers
which no people as a whole will learn except by their own experience. The
stirring spirit of life that brings man self-reliance will make him claim his
share in the ordering of his own country sooner or later but in any case
sooner than he has been able to learn that a measure is liberal or tyrannous,
not according to the type of government that imposes it but according to the
degree of liberty it secures to, or takes away from, the individuals it affects.
How many Englishmen who have ever given a thought to India have
imagined themselves for a moment as natives of that land? Try to put
yourself in the place of any native-born Indian and consider fairly what
your thought would be about politics or government. If you were a ryot, an
uneducated villager, you would know nothing of such matters. For you, all
life and its affairs would be in the hands of the gods and the money-lender,
and endeavours to assuage their wrath or cruelty, to induce their patronage
or favour, would exhaust whatever surplus energy remained from daily
rounds of toil.
But put yourself for a moment in the place of the young Mohammedan
who has just left his university and is trying to obtain a berth in the post-
office, or of a Hindoo medical assistant in the hospital of a country town, or
of a large native landowner who has just left college and succeeded to an
estate in Bengal, or of a native pleader in the courts, or of a native assistant
magistrate—would you then be quite indifferent to questions of government
and politics? You would feel conscious that you were being ruled by
strangers whose superiority, in whatever respects you deemed them
superior, was the most galling thing about them—far more so than their
habitual disclination to have more touch with you than was necessary to the
efficient discharge of their official duties. Among the very few you ever
met, after leaving college, one Englishman might seem to you lovable; but
would that reconcile you to the fact that his race was ruling yours, dividing
its territories in the teeth of the protest of their powerless inhabitants, and,
as you gathered from your reading, denying you rights of self-government
which his own people years ago had risen in arms to obtain?
But in order to give India the chance of future autonomy and

independence, we must distinguish between the extreme claims of isolated
and non-representative enthusiasts and the reasonable progressive changes
warranted by a gradual advance of liberal education and increase of
religious tolerance: we must distinguish between the exuberance of
inexperienced youths and the irritation of dissatisfied place-hunters on the
one hand and the mature opinions on the other hand of enlightened Indians
who have proved their power of wise judgment by years of serious
responsibility in positions of trust and authority. And first and last, we must
never forget, in our continued efforts to make a nation out of a tangle of
many states and peoples, the tremendous power we have gradually gained
to influence the general liberty and progress of the world, and that no part
of that power can ever be yielded up save as the shameful shifting of a
burden it is our noblest privilege to bear.
THE END
INDEX
ABORNIA, 129
Abu, Mount, 303, 306
Abu Road, 305, 306
Afghan, 231, 233, 234, 284
Afghanistan, 240, 278, 283
Afridi, 236, 240, 242, 244, 248
Aghoris, 203
Agra, 183, 184, 191, 193, 197, 320, 327
Ahmadabad, 309
Ahmednagar, 314, 316
Aindaw Pagoda, 74
Ajmere, 303-305
Akal Bunga, 220, 224
Akali, 272, 273, 274, 276
Akhbar, 181, 183, 185, 186, 187, 188, 193, 194, 197, 257, 261, 300, 304,
346
Alexander, 89
Ali Masjid, 239, 242, 243, 244, 246, 250
Aligar College, 228
Allard, 254
Amban Dance, 138
Amber, 290
Amethi, Rajah of, 156
Amias, 192
Amir of Afghanistan, 194, 229, 242, 283
Amir Khusran, 204
Amir (of Lucknow), 192
Amritsar, 217-224, 225
Annexation of Burmah, 65, 80, 81
Anundabagh, 156, 157
Aravalli Range, 303, 305
Arrakan Pagoda, 75, 78
Areca, 15, 99
Arhai-din-ka-jompra, 304, 305
Armoury, 254, 255
Assykhera, 173
Asoka, 206, 346
Assam, 100
Aurungzebe, 145, 152, 158, 194
Austin of Bordeaux, 199, 200
Australia, 175
Ava, 65
Avitabile, 228, 254
BABA ATTAL, 221

Babar, 235, 261
Bad Shahi Masjid, 253
Baluchistan, 278, 282
Bamboo, 17, 26, 37, 44, 48, 55, 69, 73, 90, 94, 99, 131, 136, 211, 233, 243,
325
Banyan tree, 23, 121, 129
Baradari, 253
Bay of Bengal, 2
Bazaars, 37, 81, 82, 166, 167, 173, 212, 231, 246, 258, 291, 328, 337
Beadon Square, 122
Bean Sing, 152
Bear, 50
Bee-eaters, 24
Begari Canal, 281
Benares, 142-162, 163, 289, 301
Benares, Maharajah of, 154, 159
Bengal Government Offices, 108
Bengali, 120, 121, 122, 125, 126, 127
Bengali theatres, 121-128
Bernard Free Library, 66
Besant, Mrs, 154
Betel, 15, 108, 124
Bhakkur Island, 279, 281
Bhamo, 39, 41-49, 77
Bhaskarananda Saraswati, 156, 157, 158
Bhils, 102
Black Mosque, 198, 207
Bodawpaya, 65
Bodh tree, 121
Bokhara, 227, 236
Bolan Pass, 278, 282, 285
Bombay, 126, 127, 225, 266
Bombay Burmah Trading Corporation, Limited, 19, 81
Bostan Junction, 282, 287
Botanical Gardens, 129, 130
Bo-tree, 144, 145
Brahma, 126, 218, 302
Brahmin, 5, 334, 335
Buddha, 14, 15, 56, 58, 59, 60, 62, 64, 75, 78, 120, 182, 217, 238
Buddhist, 259
Buddhist Society, 13-19
Buddhist Stupa, 237
Buddhist Tope, 148
Budge Bridge, 105
Burmah Oil Works, 8
Buxar, 142
CACTUS, 69, 87, 153, 290

Calcutta, 80, 100, 105-130, 141, 175, 179, 259
Camels, 240, 241, 243, 245, 247, 248, 284, 318
Cauvery, River, 93
Cawnpore, 175-180
Cawnpore Well, 179
Central Hindoo College, 154
Ceylon, 86, 99, 102, 130, 160, 284
Chagatta, 229, 232, 234
Chait Singh, Rajah, 160
Chakrayantra, 151
Chaman, 283, 285, 287
Chappa Rift, 288
Cheroot, 15, 17, 55, 80, 84
Chili, 5, 82, 230
China, 227, 349
Chinese, 42, 43, 47, 48, 49, 72, 73, 74, 109, 138, 147, 148, 183
Chitor, 299-303
Chitorgarh, 299
Chitral, 235
Chittagonians, 21
Choultry, 88
Chowringhee, 106, 109
Clive, Lord, 98
Cobra, 153
Coco-nut oil, 5
Coffee, 103
Colombo, 86
Connaught, Duchess of, 288
Cooper, Mr, 64, 65, 66
Coonoor, 100, 102, 103
Corrugated iron, 24, 37
Cotton, 87, 230, 306, 326
Cotton-mills, 86, 114, 270
Cotton, wild, 56
Cowrie money, 168, 219
Cow Temple, Benares, 147, 148
Crocodiles, 293
Crows, 76, 122, 183, 216
Curzon, Lord, 200, 219, 238
DABIR (of Lucknow), 192

Dacoit, 25, 45, 46
Dagh (of Delhi), 192
Dak tree, 210
Dal, 5, 82
Dalhousie Square, 108
Dancer, 6, 17, 45, 84, 169, 215, 271, 324
Dancing, 137, 138, 173, 285, 302, 322
Dara Shikoh, 197
Dargah, the, 303, 304
Darjeeling, 133-139
Darjeeling Himalaya Railway, 131
D'Avera, Monsieur, 42
Dehra Dun, 209-211, 215
Delhi, 128, 160, 196-208, 275
Dharbanga, 108
Dhuleep Singh, 254
Dilawar Khan, 232
Dilwarra Temples, 306-308
Diwan-i-am, 199, 201
Diwan-i-Khas, 202
Drama, 13, 16-19, 43, 47, 122-128
Dravidian, 87, 95, 102
Droog, 104
Dufferin Bridge, 151, 160
Dunlay, Private, 174
Durga Temple, Benares, 155, 156
Durian, 14
EAGLE, 24
Eastern Bengal State Railway, 106
Eastern Yomans, 23, 24
Edward the Seventh, 194, 276
Egrets, 76
Elephant Book, 96
Elephants, 19, 20, 23, 96, 97, 199, 251, 277, 296, 335, 340
Eng tree, 24
Etawah, 173
Eucalyptus, 99, 103, 211
Everest, Mount, 134, 135
FAKIRS, 147, 158, 161, 263, 341

Famine, 170, 315
Fatehpur-Sikri, 181-190, 303
Ferryshaw Siding, 39
Flamingoes, 295
Footprints, 60, 162, 333
Fort Dufferin, 77, 78
Fort Saint George, 97
Fort William, 106
France, 6, 81, 90, 224
French Legion, 254
GANESH, 91, 120, 145, 148, 300

Gangeli Khan, 234
Ganges River, 117, 136, 159, 175, 180, 333, 339
Gardens, 156, 165, 174, 272, 295
Garden Reach, 106
Gardner, Alexander, 272
Gautama, 16, 60, 76
Ghamberi, River, 299
Ghats, 150, 151, 152, 158, 159, 160, 161, 162, 180, 333, 334, 335
Ghonds, 102
Ghoom, 133
Glass, 10, 61, 62, 73, 74
Gobindaji, 293
Gokteik, 26-28
Golden Monastery, 74, 78
Golden Temple, Amritsar, 217, 218, 219, 222
Golden Temple, Benares, 144, 146, 161
Gopura, 88, 94
Gor Khatri, 227, 228, 229
Gourkhas, 79, 246, 255
Granth, 218, 219, 271, 334, 339
Grapes, 230, 293
Guru, 217, 220, 221, 223, 273
Gwalior, Maharajah of, 152
HAMADRYAD, 24
Hanuman, 120, 121, 160, 300
Hari Mandar, 218
Harnai Route, 287
Hastings, the, 7
Hastings, Marquis of, 108
Hastings Memorial, 227
Hastings, Warren, 143, 160
Hawks, 23
Himalayas, 131, 132, 134, 135, 211, 214, 279
Hindoo, 1, 2, 4, 6, 36, 39, 47, 87, 96, 100, 102, 113, 119, 120, 143, 145,
146, 147, 148, 152, 154, 159, 162, 180, 182, 186, 203, 207, 218, 228,
235, 255, 261, 281, 284, 285, 294, 302, 316, 348, 350
Hindoo Architecture, 87
Hirok, 282
Hodson, 203
Holi festival, 100, 207, 285
Hooghly, River, 105
Howrah, 106, 113, 114
Hpoongi, 37
Hsipaw, 28-38
Hsipaw, Sawbwa of, 28, 31-37
Hti, 10, 35, 74
Hulling, 21
Humayun, 202, 203, 260
Hurdwar, 333-335
Hyderabad, Deccan, 176
IDAR, 309-316
Idar Road, 309
Imambara, the Great, 170, 171, 173
Imambara, the Husainabad, 171, 173
Indus, River, 278, 281
Industrialism, 177
Irrawaddy, River, 39, 54, 56, 58
Irrawaddy, Flotilla Company, 39, 42, 54
Iron Foundry, 115
Iron Pillar, 206
Italians, 200, 201, 228
Izzat, 101
JACOBS, SIR SWINTON, 295

Jain, 205, 301, 303, 304, 307, 312
Jain Temple, 149, 152, 306, 308
Jaipur, 151, 290-295
Jama Masjid, Agra, 327
Jama Masjid, Delhi, 197, 202, 207
James and Mary, 105
Jamroud, 229, 239, 240, 241, 243
Jataka stories, 63
Java, 129
Jehanara, 204
Jehangir, 188, 189, 228, 253, 261, 262, 263
Juggernaut, 115, 120, 154
Jumna, River, 173, 199, 200, 201, 319, 330
Jute, 114, 142
Jute-mills, 106, 114
KABUL, 234, 236, 241

Kachins, 37, 48
Kali, 92, 116, 118, 120, 121
Kalighat, 116
Kampani Bagan, 128, 129
Kanishka, 237, 238
Kanutkwin, 25
Karapanasami, 91, 92
Kashmir, 225, 258
Kashmir Gate, 197
Kashmiris, 139
Katha, 40, 42
Khaskas grass, 170
Khawbgah, 181, 186
Kheddah, 20
Khyber Pass, 239-250
Kinchinjunga Mountain, 134
Kirowdi, 184
Kites, 76, 183, 278, 322
Kisshoor, 4
Kojak Pass, 283, 285
Kokand, 235
Kols, 102
Kubla Khan, 56
Kurseong, 132
Kuchi Khel, 242, 249, 250
Kutab Minar, 198, 204, 205
Kuthodaw, 78
Kyankine, 29
Kyansittha, King, 62, 63
Kyd's Monument, 130
LACQUER, 15, 56, 69, 70

Lady Canning's Seat, 104
Lahore, 233, 251, 265, 266
Lahore Gate, 199
Lalamusa, 225
Landi Kotal, 241, 243
Landour, 212, 214
Lansdowne Bridge, 278, 286
Lashio, 30
Lat, 206
Lawrence, Sir Henry, 174
Lebong, 135
Leogryphs, 8, 55
Leopard, 25
Lepchus, 139
Llama, 136
Lotus, 78, 79, 82, 183
Loungoes, 21
Lucknow, 163-174
Lugyis, 66
MADRAS, 2, 4, 6, 97, 98, 111

Madura, 87, 88, 89, 90, 95
Magwe, 68
Mahadevi, 35
Mahrattas, 113, 126, 127, 255
Maidan, 106, 109, 128
Maimyo, 3, 26
Malabar Coast, 110, 111
Malay Archipelago, 129
Mandalay, 54, 55, 56, 68, 70, 72-85
Mangi, 288
Mango, 211, 265
Mantapam, 88, 92, 95
Marionettes, 83
Marochetti, 179
Marwa, 136
Marwar, 303
Maung Nyo, 37
Mausoleum of Humayun, 202, 203
Mayo College, 305
Mayo School of Industrial Art, 258
Mecca, 171, 236
Meerut, 196, 206
Merthil Swami, 156, 157, 158
Mettapalaiyam, 99
Mewar, 295, 297, 299, 303
Minah, 183
Minachi, 87
Mohammed, 249
Mohammedan, 5, 6, 115, 145, 146, 152, 154, 162, 164, 169, 177, 191, 193,
194, 195, 205, 228, 229, 235, 261, 263, 281, 283, 291, 317, 330, 348,
350
Moharam Festival, 171, 191, 317, 332
Mongolian, 5, 102
Monkeys, 153, 155, 306, 337
Moplas, 110, 111
Mora, 41
Morison, Theodore, 347
Mosi Temple, 151
Mowgwa, 184
Mukolo, 69
Munro, Major Hector, 142
Munshi tree, 118
Museums, 148, 149, 173, 238, 258, 295
Music, 17, 44, 91, 97, 124, 161, 170, 184, 271, 285, 322, 339
Mussoorie, 211, 212, 213, 215
Mutaa, 169
Mutiny, the, 143, 164, 165, 170, 174, 197, 206, 207
Muttra, 293
Myrabolams, 177
NABANG, 29
Nabha, 266-277
Nabha, Rajah of, 266, 267, 268, 269, 274, 275, 276, 277
Nagas, 102, 334
Naggra, 184
Nagpur, 152
Nana Sahib, 180
Nandi, 95, 335
Narapatisezoo, King, 59
Natindaw, 66, 67, 68
Nats, 54, 63, 65, 66, 67, 68
Natsin, 68
Naurata, King, 62, 63, 68
Nautch, 6
Nayaka Dynasty, 90
Neem tree, 121, 161, 179
Nepaul, 128, 152
Nepaulis, 139
Ngapi, 24
Nicholson, General, 196, 197
Nilgiri Hills, 99
Nizam, the, 192
Nizam-ud-Din-Aulia, 204
Nour Jehan, 188, 189, 190, 192, 228, 261, 263, 264
Nyaungoo, 54, 55, 57, 64, 68
Nynung, 23
OBSERVATORIES, 151, 292

Ochterlony, Sir David, 106, 197
Ootacamund, 100, 102
Onslow Ford, 108
Opium, 273
Oshuck tree, 121
Otto of Roses, 170
Oudh, Nawab of, 142
PAGAN, 55-71
Pagodas, 7, 8-12, 39, 49, 58, 59, 74, 75, 78
Palmyra palm, 87
Parrots, 92, 184, 258, 270, 295, 337
Parsee, 121, 348
Peacocks, 25, 138, 290, 296, 323, 331
Peacock hawk, 24
Peacock Throne, 199
Peepul tree, 121, 180, 211, 291
Pegu, 23, 62, 63
Pegu River, 8
Peshawar, 225-237, 239, 240, 241, 246, 260, 261, 262
Phulkian States, 266, 269
Plague, 8, 29, 290, 314
Plantain, 37, 82
Polyandry, 102
Pomegranates, 230, 293
Poogi, 29
Poozoondoung, 19, 20
Popa, 65
Potter, 153
Powkpin, 24
Prayer-wheels, 136, 137
Prendergast, General, 80
Punjabis, 79, 210, 218
Pwe, 13, 16-19, 43-48, 83, 84, 85
Python, 153, 336
QUEEN'S COLLEGE, Benares, 143

Queen's Golden Monastery, 74, 78
Queen Victoria, 34, 171, 271, 279
Quetta, 282, 283, 285, 286
RADHA, 120
Rakhykash, 335-340
Rajpur, 211, 215
Rama, 160, 300
Rameswaram Temple, 121
Rangoon, 1-22, 23, 66, 75, 80, 105, 238
Rangoon River, 8
Ranjeet Singh, 228, 254, 256, 261, 268, 272, 273
Ravi River, 256, 262
Residency, Lucknow, the, 164, 165
Rhinoceros, 128
Rice, 1, 76, 82, 219, 230, 304
Rice mills, 20, 21
Rishi, 97
Rose, 82, 156, 183
Royal Lakes, 12
Runjeet River, 135, 136
Runnymede, 99
Ruri, 279, 280
SADHUS, 334
St Mary's Church, Madras, 98
St Paul's Cathedral, Calcutta, 112
Sal, 211
Salay, 64
Salim Chisti, 186, 187, 188
Samrat Yantra, 151
Sandalwood, 37, 162, 307
Sankarati Puja Festival, 113
Santals, 102
Sarnath, 148, 149
Sarwarnath, 335
Saturday god, 147
Sawche, 28, 32, 37
Screwpines, 130, 132
Scythian, 102
Sedaw, 26
Segaw, 41
Sepaya, Queen, 80
Sesamum, 15, 230
Seychelles, 130
Shaddra, 261, 262
Shahijikidheri, 237
Shah Jehan, 197, 204, 264
Shan States, 23, 26-38
Shannon, 179
Shias, 325, 330
Shikarpur, 278
Shwe Dagon, 7, 8-12, 75
Shwemetyna, 66, 68
Siam, 130
Sibi Junction, 282
Sikandra, 181, 193, 194, 195
Sikhs, 79, 218, 220, 223, 255, 262, 268, 271, 273, 274, 334, 338, 348
Sikkim, 136, 139
Sikra, 95
Siliguri, 131, 141
Silk, 82, 227, 269, 274
Sind Desert, 278
Singh, Sir Pratap, 309, 313-316
Sinkan, 50
Siriam, 7, 8
Sita, 160
Siva, 90, 96, 116, 117, 118, 120, 121, 145, 146, 153, 180, 297, 300, 302,
335
Siwaliks, 215
Snipe, 23
Sookua, 131
Soutakar, 4
South Indian Railway, 87
Srirangam, 93, 94
Stambham, 88
Sugar-cane, 142, 230, 318
Sukkur, 278, 279, 281
Sundareswara Temple, 87
TAGAUNG, 66
Taj Mahal, 319
Tamarind, 5, 82
Tanjore, 90, 95, 96
Tappakulam, 88, 92
Tartara, Mount, 228
Tea, 103
Teak, 8, 19, 40
Teester River, 136
Thaton, 62, 68
Thebaw, King, 42, 78, 80, 81
Thibetans, 133, 137, 138, 139
Thurligyaung, 67
Tiger, 25
Tiger Hill, 134, 135
Tikka Gharry, 9, 14
Tindaria, 132
Tippoo Sultan, 104
Tirah Hills, 250
Tobacco, 230
Todas, 102
Toddy palms, 130, 153
Tongu, 30
Tower Bridge, 7
Tree-ferns, 103, 132, 140
Tree-climbing perch, 24
Trichinopoly, 89, 90, 91, 92, 93, 94, 95
Tsar of Russia, 194
Turtles, 76
Tuticorin, 86, 284
UDAIPUR, 295-299
Udaipur, Maharana of, 297-299
Ulabaria, 114
VAISHNAVAS, 118, 121

Vallam, 90
Ventura, 254
Verloocooli, 4
Vimana, 88
Vishnu, 94, 118, 120, 121, 145, 152, 162, 206, 302
Vizianagram, Maharajah of, 154
Vultures, 68, 184, 322
WATER-SNAKE, 13
Wazirabad, 225
Waziristan, 258
Western Yomans, 23, 24
Wheat, 230, 233
Woollen mills, 175
YAK, 138
ZAKKA KHELS, 234, 246

Zam Zammah, 257
Zenana, 124, 126, 293
Zoological Gardens, 51, 128
EDINBURGH
COLSTONS LIMITED
PRINTERS
*** END OF THE PROJECT GUTENBERG EBOOK THROUGH
INDIA AND BURMAH WITH PEN AND BRUSH ***
Updated editions will replace the previous one—the old editions will
be renamed.
Creating the works from print editions not protected by U.S.

copyright law means that no one owns a United States copyright in
these works, so the Foundation (and you!) can copy and distribute it
in the United States without permission and without paying copyright
royalties. Special rules, set forth in the General Terms of Use part of
this license, apply to copying and distributing Project Gutenberg™
electronic works to protect the PROJECT GUTENBERG™ concept
and trademark. Project Gutenberg is a registered trademark, and
may not be used if you charge for an eBook, except by following the
terms of the trademark license, including paying royalties for use of
the Project Gutenberg trademark. If you do not charge anything for
copies of this eBook, complying with the trademark license is very
easy. You may use this eBook for nearly any purpose such as
creation of derivative works, reports, performances and research.
Project Gutenberg eBooks may be modified and printed and given
away—you may do practically ANYTHING in the United States with
eBooks not protected by U.S. copyright law. Redistribution is subject
to the trademark license, especially commercial redistribution.
START: FULL LICENSE

THE FULL PROJECT GUTENBERG LICENSE
PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK
To protect the Project Gutenberg™ mission of promoting the free

distribution of electronic works, by using or distributing this work (or
any other work associated in any way with the phrase “Project
Gutenberg”), you agree to comply with all the terms of the Full
Project Gutenberg™ License available with this file or online at
www.gutenberg.org/license.
Section 1. General Terms of Use and

Redistributing Project Gutenberg™
electronic works
1.A. By reading or using any part of this Project Gutenberg™
electronic work, you indicate that you have read, understand, agree
to and accept all the terms of this license and intellectual property
(trademark/copyright) agreement. If you do not agree to abide by all
the terms of this agreement, you must cease using and return or
destroy all copies of Project Gutenberg™ electronic works in your
possession. If you paid a fee for obtaining a copy of or access to a
Project Gutenberg™ electronic work and you do not agree to be
bound by the terms of this agreement, you may obtain a refund from
the person or entity to whom you paid the fee as set forth in
paragraph 1.E.8.
1.B. “Project Gutenberg” is a registered trademark. It may only be

used on or associated in any way with an electronic work by people
who agree to be bound by the terms of this agreement. There are a
few things that you can do with most Project Gutenberg™ electronic
works even without complying with the full terms of this agreement.
See paragraph 1.C below. There are a lot of things you can do with
Project Gutenberg™ electronic works if you follow the terms of this
agreement and help preserve free future access to Project
Gutenberg™ electronic works. See paragraph 1.E below.
1.C. The Project Gutenberg Literary Archive Foundation (“the
Foundation” or PGLAF), owns a compilation copyright in the
collection of Project Gutenberg™ electronic works. Nearly all the
individual works in the collection are in the public domain in the
United States. If an individual work is unprotected by copyright law in
the United States and you are located in the United States, we do
not claim a right to prevent you from copying, distributing,
performing, displaying or creating derivative works based on the
work as long as all references to Project Gutenberg are removed. Of
course, we hope that you will support the Project Gutenberg™
mission of promoting free access to electronic works by freely
sharing Project Gutenberg™ works in compliance with the terms of
this agreement for keeping the Project Gutenberg™ name
associated with the work. You can easily comply with the terms of
this agreement by keeping this work in the same format with its
attached full Project Gutenberg™ License when you share it without
charge with others.
1.D. The copyright laws of the place where you are located also
govern what you can do with this work. Copyright laws in most
countries are in a constant state of change. If you are outside the
United States, check the laws of your country in addition to the terms
of this agreement before downloading, copying, displaying,
performing, distributing or creating derivative works based on this
work or any other Project Gutenberg™ work. The Foundation makes
no representations concerning the copyright status of any work in
any country other than the United States.
1.E. Unless you have removed all references to Project Gutenberg:
1.E.1. The following sentence, with active links to, or other

immediate access to, the full Project Gutenberg™ License must
appear prominently whenever any copy of a Project Gutenberg™
work (any work on which the phrase “Project Gutenberg” appears, or
with which the phrase “Project Gutenberg” is associated) is
accessed, displayed, performed, viewed, copied or distributed:
This eBook is for the use of anyone anywhere in the United
States and most other parts of the world at no cost and with
almost no restrictions whatsoever. You may copy it, give it away
or re-use it under the terms of the Project Gutenberg License
included with this eBook or online at www.gutenberg.org. If you
are not located in the United States, you will have to check the
laws of the country where you are located before using this
eBook.
1.E.2. If an individual Project Gutenberg™ electronic work is derived

from texts not protected by U.S. copyright law (does not contain a
notice indicating that it is posted with permission of the copyright
holder), the work can be copied and distributed to anyone in the
United States without paying any fees or charges. If you are
redistributing or providing access to a work with the phrase “Project
Gutenberg” associated with or appearing on the work, you must
comply either with the requirements of paragraphs 1.E.1 through
1.E.7 or obtain permission for the use of the work and the Project
Gutenberg™ trademark as set forth in paragraphs 1.E.8 or 1.E.9.
1.E.3. If an individual Project Gutenberg™ electronic work is posted

with the permission of the copyright holder, your use and distribution
must comply with both paragraphs 1.E.1 through 1.E.7 and any
additional terms imposed by the copyright holder. Additional terms
will be linked to the Project Gutenberg™ License for all works posted
with the permission of the copyright holder found at the beginning of
this work.
1.E.4. Do not unlink or detach or remove the full Project

Gutenberg™ License terms from this work, or any files containing a
part of this work or any other work associated with Project
Gutenberg™.
1.E.5. Do not copy, display, perform, distribute or redistribute this

electronic work, or any part of this electronic work, without
prominently displaying the sentence set forth in paragraph 1.E.1 with
active links or immediate access to the full terms of the Project
Gutenberg™ License.
1.E.6. You may convert to and distribute this work in any binary,
compressed, marked up, nonproprietary or proprietary form,
including any word processing or hypertext form. However, if you
provide access to or distribute copies of a Project Gutenberg™ work
in a format other than “Plain Vanilla ASCII” or other format used in
the official version posted on the official Project Gutenberg™ website
(www.gutenberg.org), you must, at no additional cost, fee or expense
to the user, provide a copy, a means of exporting a copy, or a means
of obtaining a copy upon request, of the work in its original “Plain
Vanilla ASCII” or other form. Any alternate format must include the
full Project Gutenberg™ License as specified in paragraph 1.E.1.
1.E.7. Do not charge a fee for access to, viewing, displaying,

performing, copying or distributing any Project Gutenberg™ works
unless you comply with paragraph 1.E.8 or 1.E.9.
1.E.8. You may charge a reasonable fee for copies of or providing

access to or distributing Project Gutenberg™ electronic works
provided that:
• You pay a royalty fee of 20% of the gross profits you derive from
the use of Project Gutenberg™ works calculated using the
method you already use to calculate your applicable taxes. The
fee is owed to the owner of the Project Gutenberg™ trademark,
but he has agreed to donate royalties under this paragraph to
the Project Gutenberg Literary Archive Foundation. Royalty
payments must be paid within 60 days following each date on
which you prepare (or are legally required to prepare) your
periodic tax returns. Royalty payments should be clearly marked
as such and sent to the Project Gutenberg Literary Archive
Foundation at the address specified in Section 4, “Information
about donations to the Project Gutenberg Literary Archive
Foundation.”
• You provide a full refund of any money paid by a user who

notifies you in writing (or by e-mail) within 30 days of receipt that
s/he does not agree to the terms of the full Project Gutenberg™
License. You must require such a user to return or destroy all
copies of the works possessed in a physical medium and
discontinue all use of and all access to other copies of Project
Gutenberg™ works.
• You provide, in accordance with paragraph 1.F.3, a full refund of

any money paid for a work or a replacement copy, if a defect in
the electronic work is discovered and reported to you within 90
days of receipt of the work.
• You comply with all other terms of this agreement for free
distribution of Project Gutenberg™ works.
1.E.9. If you wish to charge a fee or distribute a Project Gutenberg™

electronic work or group of works on different terms than are set
forth in this agreement, you must obtain permission in writing from
the Project Gutenberg Literary Archive Foundation, the manager of
the Project Gutenberg™ trademark. Contact the Foundation as set
forth in Section 3 below.
1.F.
1.F.1. Project Gutenberg volunteers and employees expend

considerable effort to identify, do copyright research on, transcribe
and proofread works not protected by U.S. copyright law in creating
the Project Gutenberg™ collection. Despite these efforts, Project
Gutenberg™ electronic works, and the medium on which they may
be stored, may contain “Defects,” such as, but not limited to,
incomplete, inaccurate or corrupt data, transcription errors, a
copyright or other intellectual property infringement, a defective or
damaged disk or other medium, a computer virus, or computer
codes that damage or cannot be read by your equipment.
1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except

for the “Right of Replacement or Refund” described in paragraph
1.F.3, the Project Gutenberg Literary Archive Foundation, the owner
of the Project Gutenberg™ trademark, and any other party
distributing a Project Gutenberg™ electronic work under this
agreement, disclaim all liability to you for damages, costs and
expenses, including legal fees. YOU AGREE THAT YOU HAVE NO
REMEDIES FOR NEGLIGENCE, STRICT LIABILITY, BREACH OF
WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE
PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE
FOUNDATION, THE TRADEMARK OWNER, AND ANY
DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE LIABLE
TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL,
PUNITIVE OR INCIDENTAL DAMAGES EVEN IF YOU GIVE
NOTICE OF THE POSSIBILITY OF SUCH DAMAGE.
1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you

discover a defect in this electronic work within 90 days of receiving it,
you can receive a refund of the money (if any) you paid for it by
sending a written explanation to the person you received the work
from. If you received the work on a physical medium, you must
return the medium with your written explanation. The person or entity
that provided you with the defective work may elect to provide a
replacement copy in lieu of a refund. If you received the work
electronically, the person or entity providing it to you may choose to
give you a second opportunity to receive the work electronically in
lieu of a refund. If the second copy is also defective, you may
demand a refund in writing without further opportunities to fix the
problem.
1.F.4. Except for the limited right of replacement or refund set forth in
paragraph 1.F.3, this work is provided to you ‘AS-IS’, WITH NO
OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR ANY PURPOSE.
1.F.5. Some states do not allow disclaimers of certain implied

warranties or the exclusion or limitation of certain types of damages.
If any disclaimer or limitation set forth in this agreement violates the
law of the state applicable to this agreement, the agreement shall be
interpreted to make the maximum disclaimer or limitation permitted
by the applicable state law. The invalidity or unenforceability of any
provision of this agreement shall not void the remaining provisions.
1.F.6. INDEMNITY - You agree to indemnify and hold the
Foundation, the trademark owner, any agent or employee of the
Foundation, anyone providing copies of Project Gutenberg™
electronic works in accordance with this agreement, and any
volunteers associated with the production, promotion and distribution
of Project Gutenberg™ electronic works, harmless from all liability,
costs and expenses, including legal fees, that arise directly or
indirectly from any of the following which you do or cause to occur:
(a) distribution of this or any Project Gutenberg™ work, (b)
alteration, modification, or additions or deletions to any Project
Gutenberg™ work, and (c) any Defect you cause.
Section 2. Information about the Mission of

Project Gutenberg™
Project Gutenberg™ is synonymous with the free distribution of
electronic works in formats readable by the widest variety of
computers including obsolete, old, middle-aged and new computers.
It exists because of the efforts of hundreds of volunteers and
donations from people in all walks of life.
Volunteers and financial support to provide volunteers with the

assistance they need are critical to reaching Project Gutenberg™’s
goals and ensuring that the Project Gutenberg™ collection will
remain freely available for generations to come. In 2001, the Project
Gutenberg Literary Archive Foundation was created to provide a
secure and permanent future for Project Gutenberg™ and future
generations. To learn more about the Project Gutenberg Literary
Archive Foundation and how your efforts and donations can help,
see Sections 3 and 4 and the Foundation information page at
www.gutenberg.org.
Section 3. Information about the Project

Gutenberg Literary Archive Foundation
The Project Gutenberg Literary Archive Foundation is a non-profit
501(c)(3) educational corporation organized under the laws of the
state of Mississippi and granted tax exempt status by the Internal
Revenue Service. The Foundation’s EIN or federal tax identification
number is 64-6221541. Contributions to the Project Gutenberg
Literary Archive Foundation are tax deductible to the full extent
permitted by U.S. federal laws and your state’s laws.
The Foundation’s business office is located at 809 North 1500 West,

Salt Lake City, UT 84116, (801) 596-1887. Email contact links and up
to date contact information can be found at the Foundation’s website
and official page at www.gutenberg.org/contact
Section 4. Information about Donations to

the Project Gutenberg Literary Archive
Foundation
Project Gutenberg™ depends upon and cannot survive without
widespread public support and donations to carry out its mission of
increasing the number of public domain and licensed works that can
be freely distributed in machine-readable form accessible by the
widest array of equipment including outdated equipment. Many small
donations ($1 to $5,000) are particularly important to maintaining tax
exempt status with the IRS.
The Foundation is committed to complying with the laws regulating

charities and charitable donations in all 50 states of the United
States. Compliance requirements are not uniform and it takes a
considerable effort, much paperwork and many fees to meet and
keep up with these requirements. We do not solicit donations in
locations where we have not received written confirmation of
compliance. To SEND DONATIONS or determine the status of
compliance for any particular state visit www.gutenberg.org/donate.
While we cannot and do not solicit contributions from states where

we have not met the solicitation requirements, we know of no

Ebook Thermodynamic Analysis and Optimization of Geothermal Power Plants PDF Full Chapter PDF

Uploaded by

Copyright:

Available Formats

Ebook Thermodynamic Analysis and Optimization of Geothermal Power Plants PDF Full Chapter PDF

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Ebook Thermodynamic Analysis and Optimization of Geothermal Power Plants PDF Full Chapter PDF

Uploaded by

Copyright:

Available Formats

Thermodynamic Analysis and

Optimization of Geothermal Power

Copyright © 2021 Elsevier Inc. All rights reserved.

Library of Congress Cataloging-in-Publication Data

For information on all Elsevier publications

Publisher: Brian Romer

Typeset by SPi Global, India

Various cycle configurations for

1.1 Introduction reservoir [8]. Depending upon the location, temperature,

Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00005-6

PW Production well BCV Ball check valve SV Stop valve

TABLE 1.1 Equations used for thermodynamic state analysis [15].

Condensing process m_ cw ¼ x2 m_ total hcDT

1.2.2 Double-flash steam power plants

PW Production well SV Stop valve MR Moisture remover

State Main characteristics Equation Equation number

W_ hpt ¼ m_ hps whpt ¼ x2 m_ total whpt (1.21)

wlpt ¼ h9 h10 (1.26)

W_ lpt ¼ m_ 9 ðh9 h10 Þ (1.27)

W_ total ¼ W_ hpt + W_ lpt (1.31)

W_ e , gross ¼ g W_ total (1.32)

FIG. 1.5 Dry-steam geothermal power plant [9, 17].

FIG. 1.7 Basic binary geothermal power plant [17, 18].

The analysis of geothermal fluid and the working fluid

W_ t ¼ m_ wf wt ¼ m_ wf t ðh1 h2s Þ (1.39)

Few studies have focused on the geothermal and biomass Acknowledgments

Global value chain and manufacturing

Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00007-X

TABLE 2.1 Inconel alloy element compositions by weight.

calculated based on the average power consumption of each

can be set as a threshold based on manufacturers’ annual

Raw Material Purchased MaterialEstimated Volume Material Estimated Material Cost

Impeller Titanium Plate 22.82 39.04 0.037 4,500 167 6,500

Process Machine Manufacturing

5-Axis CNC Rest Milling 42.0 8.0 35 1,760

10 Units (Standard Design)

Drilling 0.3 0.2 35 9 Rest Milling

5-Axis CNC Rest Milling 4.2 8.0 35 440

turboexpander has an MSP of 226 $/kW at a manufacturing

Design & Engineering

Selling, General & Administration

Selling, General & Design &

Design & Engineering

Selling, General & Administration

Selling, General & Design &

GTO CEMAC ORC

FIG. 2.17 Off-design turbine efficiency curve.

FIG. 2.18 Actual plant brine effectiveness.

Production well flow rate kg/s 80 Inflation rate % 2.5

Number of injection wells – 1 Nominal discount rate %/ 8.15

TABLE 2.8 Summary of financial parameters used to calculate financial outputs.

l Standard turbines are more cost-effective than custom

Acknowledgments [16] MENR. Turkish Ministry of Energy and Natural Resources

CO2 emissions from geothermal power

3.1 Introduction concentration will be higher. In igneous rocks, the carbonate

Thermodynamic Analysis and Optimization of Geothermal Power Plants. https://doi.org/10.1016/B978-0-12-821037-6.00012-3

But in order to give India the chance of future autonomy and

BABA ATTAL, 221

CACTUS, 69, 87, 153, 290