B E C F: A L R F R A: Uilding Nergy Onsumption Actors Iterature Eview and Uture Esearch Genda
B E C F: A L R F R A: Uilding Nergy Onsumption Actors Iterature Eview and Uture Esearch Genda
B E C F: A L R F R A: Uilding Nergy Onsumption Actors Iterature Eview and Uture Esearch Genda
ABSTRACT
The Sri Lankan energy supply system faces several major strategic challenges due to high annual
electricity demand growth rate and hence it is required to double the electricity generation capacity in
every ten years. Ministry of Power and Energy predicted regular power cuts in the foreseeable future
due to lack of rainfall within the hydro-catchments areas. In the coming years, oil price hikes will have
a great impact on the operation of thermal power plants. Sri Lanka has now become the highest
electricity bill spender in Asia and the status of energy poverty seems rather alarming. Sri Lankan
energy statistics confirm that the building sector has contributed heavily on the energy, exceeding the
industrial and transportation sectors. Occupant behaviour toward energy consumption have a
significant impact on energy poverty and the initiation of large scale development projects after the
three decades conflict pave the way to energy poverty to step up. In order to alleviate energy poverty, it
is important to investigate the factors influencing the building energy consumption and their impact on
power crisis. Therefore, the aim of this paper is to critically review the factors affecting building
energy consumption. A comprehensive literature review and a desk study of Sri Lankan energy reports
were used out to investigate the power crisis in Sri Lanka and the factors influencing building energy
consumption. Five factors and 36 sub factors identified from the literature review will be used to
identify critical factors affecting building energy consumption during the next phase of the study.
Keywords: Energy Poverty, Power Crisis, Building Energy Consumption, Building Energy
Consumption Factors.
1. INTRODUCTION
The planet is progressively stepping towards a serious energy crisis due to an escalating energy demand
compared to supply. Energy crisis is a situation in which the nation suffers from a disruption of energy
supplies accompanied by rapidly increasing energy prices that threaten economic and national security
(Williams and Alhajji, 2003). Energy consumption causes a wide range of environmental problems, and
with the increase in energy demand, the issue of energy crisis becomes cited. Energy use has recently
become a major issue due to growing concern about CO2 and other greenhouse gas emissions and the
scarceness of fossil fuels (Escrivá-Escrivá, 2011). According to the current statistics and demands, the
world's oil reserves will decline by 2052, gas resources are expected to run out within the next 60 years
and coal will dwindle within the next 80 years (Dissanayake, 2012). Yanbin et al. (2011) states that in 21st
century, all countries are facing the challenge of energy, whilst power crisis is one of the greatest crises in
energy.
This study therefore, aims at finding factors influencing building energy consumption and to set future
research agenda. The paper structure begins with a literature review on Sri Lankan energy crisis and
building energy consumption. The paper then reviews major influential factors on building energy
consumption and finally presents the discussion and future research agenda.
*
Corresponding Author: E-mail - nawodads@gmail.com
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last two decades. Thhe assessmeent of the Ceylon Electrricity Board (CEB) reveeals that thee demand for
electricitty will increease by 7-10% per annum
m over the next
n twenty years, therebby, demand shall doublee
every tenn years (Abeeygunawardaana, 2008). Therefore,
T it is required to
t double thee electricity generation
g inn
every tenn years (Abeeygunawardaana, 2011).
The largge-scale consstruction andd developmennt projects, following
f thee end of threee decades conflict
c in Srri
Lanka pave the wayy to energy poverty
p to step up (Wijeekoon, 20122). Sri Lankaa Energy Baalance (2007)
anticipatted a parallell growth in energy
e demaand, with thee rapid econoomic developpment drive launched byy
the Sri Lankan govvernment. Coonsequently,, the influx of foreign investments to the coun ntry and thee
populatioon explosionn over the last few years had been th he principal reasons
r for tthe excessivee demand for
electricitty at presentt (Wijeykoonn, 2012). Ass energy demmand rises, thhe energy coonsumption in Sri Lankaa
has becoome an act of suffer, beinng the highest electricity
y bill spenderr in Asia (Kuumara, 2011). Hence, thee
status off energy poveerty in Sri Laanka seems rather
r alarming.
Accordinng to Abeyggunawardanaa (2008), a dialogue
d on the
t energy crisis commeenced in Sri Lanka in thee
eighties when the gooal of utilisinng the electriccity generateed from the newly
n ructed reservoir system of
constru
the Mahhaweli schem me to feed thhe power neeeds of the en ntire nation and even seell excess po
ower to Indiaa
turned innto a pipe dream.
d Abeygunawardana (2008) furrther explainned that the anticipated outputs o weree
never acchieved due to various environmenntal and tech hnological problems
p andd “electricity
y” became a
permaneent crisis in Sri
S Lanka.
Thus, the energy genneration attention has turrned towardss the thermaal power apart from hydrro power andd
other doomestic enerrgy sources such as wind and bio omass. Accoording to Jeerome (2009 9), CEB hadd
diversified into therm
mal power inn the interest of speedy caapacity augm
mentation. Figure 1 show ws the thermaal
and hydrro power genneration mixx from 1995 to t 2008. Acccording to thhe figure, theere is a clear increment inn
thermal power
p generration and deecline in hydrro power gen
neration during last two ddecades.
120%
100%
80%
Power Mix
60%
40%
20%
0%
1995
5 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Thermal %
19% 19% 28% 30% 32% 35% 39% 39% 44% 44% 46% 46% 46% 49%
Hydro 81%
% 81% 72% 70% 68% 65% 61% 61% 56% 55% 54% 54% 54% 51%
Figure 1: Theermal and Hyddro Power Geeneration Mix during 1995-22008
(Soource: Econommic and Sociall Statistics of Sri Lanka 20009 cited Jerom
me 2009)
Indratisssa (2010) poiinted out thaat the Sri Laankan energy
y future is unncertain as thhe electricity
y mix is veryy
much deepending on imported fosssil fuel. In the t coming years,
y oil priice hikes willl have a greeat impact onn
thermal power plantts and climaate change will w interruptt the hydro power geneeration and therefore,
t Srri
Lanka caannot sustainn with the existing energyy mix in the years
y to comme (Abeygunnawardana, 20 011).
The pressent trend off increasing energy demaand will con ntinue while increasing eenergy costs and demandd
side mannagement measures mighht dampen the t rate of growth of energy demandd (Sri Lankaa Sustainablee
Energy Authority, 2007).
2 Therrefore, solutiions should adhere andd there is trremendous potential for
alleviatinng energy pooverty by redducing energyy consumption or conserrving energy itself.
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12000
7819.4
8223
Electricity consumption Gwh
7252.8
10000
6186.6
6763
5707.6
8000
6000
4000 Electricity Consumption
0
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Year
Figure 2: Trend Analysis of Total Energy Consumption in Sri Lanka from 2002 to 2015
(Source: Adapted from SSEA, 2010)
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According to the above review, ‘climate’, ‘building related characteristics’, ‘building systems and/services
related characteristics’, ‘occupant related characteristics’, ‘socio-economic and legal related
characteristics’ are the most frequently addressed factors influencing building energy consumption. A
review of these major factors now follows.
4.1. CLIMATE
Building acts as a climatic modifier, separating the indoor built environment from the external climate
(Lam et al., 2005). Energy demand of buildings is influenced by many climatic parameters (Kalamees et
al., 2012). Drake and Foster (1995) categorised the short-term behaviour of the atmosphere as “weather”,
while the investigation of long-term trends in the weather system as “climate”. Ministry of Construction of
People’s Republic of China (1993 as cited in Wan et al., 2011) identifies five climatology (climate types),
namely severe cold, cold, hot summer and cold winter, mild, and hot summer and warm winter. The extent
to which overall energy use for space conditioning would depend very much on the prevailing local
climates and the actual climate change in future years (Wan et al., 2011). Jim and Peng (2012) identified
weather as a huge influential factor on building energy consumption in Hong Kong. Wan et al. (2011)
listed temperature, solar radiation, wind speed/direction, moisture content of air as major weather
parameters.
Kalamees et al. (2012) stated that in a cold climate, temperature has the strongest influence on the heating
energy demand, and during summer, it has a similar influence on the cooling energy demand. The peak of
Heating Ventilation and Air Conditioning (HVAC) occurred in the heating season, while the trough of
HVAC occurred in the cooling season whereas, the peak of Hot Water Supply (HWS) occurred in cooling
season where trough of HWS occurred in heating season due to the weather conditions (Yu et al., 2011).
According to Liu and Harris (2008), a small rise in ambient temperature could still give rise to a
significant reduction in building energy consumption. Yu et al. (2011) discussed the impact of weather
conditions on occupant behaviour and thereby on building energy consumption. Climatic data are however
crucial for the building industry since a building’s role is to provide comfortable and protective indoor
conditions to its occupants against outdoor environment (Oxizidis et al., 2008).
Although the Sri Lankan context is not largely affected by seasonal climatic changes, SSEA (2008)
identifies three climatic zones as warm-humid (Dry Bulb Temperature (DBT) - 3100C, Wet Bulb
Temperature (WBT) - 2700C), warm-dry (DBT- 3300C, WBT- 2600C) and uplands (DBT- 2800C, WBT-
2300C). The outdoor design condition would vary based on the corresponding climatic zone and this will
in turn dictate the thermo-physical properties of all building elements (SSEA, 2008). Therefore, climate
can be identified as a major factor affecting building energy consumption in Sri Lanka. Further, long-term
trend, which is ‘climatology’ and short-term behaviour of the atmosphere, i.e. ‘weather’ can be identified
as two sub factors under the ‘climate’ category.
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characteristics such as building shape, thermal insulation, wall colour, window-to-wall ratio, glazing
material, shading devices and green roof system.
According to the literature review presented in Table 1, type, age, size, class, usage hours, geographical
location, design/structural parameters, orientation, envelop, construction quality, worker density, share of
areas served by air-conditioning, lift and illumination, indoor environmental/thermal quality, nature of
surrounding, rent and availability of infrastructure were identified as sub factors of ‘building related
characteristics’. These building related characteristics have very high impact on building energy
consumption. Therefore, owners can considerably save energy by considering and upgrading the
aforementioned building related characteristics.
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conditioning systems (individual units in windows or walls) consume only 34% of the cooling energy for
those with central systems. Further, SSEA (2008) provides designs and/or retrofits on
selection/specification, operation and maintenance, efficiency for Lighting, Ventilation and Air-
conditioning, and service water heating through ‘the code of practice for energy efficient buildings in Sri
Lanka’ to reduce energy consumption and reduced electricity demand in the country.
According to the review shown in Table 1, the ‘building services and systems related characteristics’
consists of seven sub factors, such as building services and systems specification, building services and
systems load, operation and maintenance schemes, efficiency/condition of building services and systems,
age of building services and systems, sub facilities/services offered and appliance ownership. Due to the
long lifespan of buildings, it is important to increase the energy efficiency of the existing building services
and systems by reducing energy use and utility costs, while guaranteeing comfort for the building’s
occupants. Therefore, proper selection, commissioning, installation, operation and maintenance of services
and systems within a built-environment are essential for the energy conservation.
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building sector to the nation’s total energy consumption. Since, the status of energy poverty in Sri Lanka
seems rather alarming, any decrease in energy usage in buildings would lead to significant energy
conservation in the total energy consumption, hence alleviating the energy shortage.
Many factors are affecting the building energy consumption. The study identified five major factors,
namely, ‘climate’, ‘building related characteristics’, ‘building systems and services related characteristics’,
‘occupant related characteristics’, ‘socio-economic and legal related characteristics’ and 36 sub factors by
reviewing 20 research papers.
Under the ‘climate’ category, climatology and weather were identified as sub factors affecting energy
usage of a building. The type, age, size, class, usage hours, geographical location, design/structural
parameters, orientation, envelop, construction quality, worker density, share of areas served by air-
conditioning, lift and illumination, indoor environmental / thermal quality, nature of surrounding, rent and
availability of infrastructure were identified as sub factors of ‘building related characteristics’. Further,
four sub factors, namely, occupancy rate, occupant behaviour/activities, preference relevant to indoor
comfort and awareness on energy consumption were identified under the ‘occupant related
characteristics’. The ‘building services and systems related characteristics’ consists of seven sub factors,
such as building services and systems specification, building services and systems load, operation and
maintenance schemes, efficiency/condition of building services and systems, age of building services and
systems, sub facilities / services offered and appliance ownership. Moreover, ‘socio-economic and legal
related characteristics’ comprises of seven factors, i.e. education, culture, income, age of the
head/householder, availability of energy resources locally, energy market prices and energy use
regulations.
Although the study identified a comprehensive set of five main categories and 36 sub factors affecting
building energy usage, there is a common rule of thumb that roughly 80% of the effects come from 20%
of the causes (Pareto Rule). Therefore, it is interesting and essential to identify key factors affecting
building energy usage in order to reduce total energy consumption in an efficient and effective manner.
Therefore, the article motivates an agenda for future research that advocates the identification of key
factors affecting building energy consumption, from the factors identified through the critical review.
These key factors can be used to reduce building energy consumption when designing new buildings and
making improvements to existing buildings and hence to alleviate energy poverty in Sri Lanka in future.
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