Generation Hydro
Generation Hydro
Generation Hydro
•Generation
•Transmission
•Distribution
Thermal
Hydro
Generation Nuclear
Methods Wind
Solar
……
Electricity Generation Sources: Two Different years
16th August 2020 17th August 2020 07th October 2020
Hydro 14.8 GWh 42% 13.87 GWh 50% 17.11 GWh 46%
Thermal - Coal 17.66 GWh 50% 9.02 GWh 32% 19.39 GWh 40%
Thermal - Oil 0.93 GWh 5% 4.15 GWh 15% 4.94 GWh 12%
Other
renewable
Solar 1.84 GWh 3% 0.58 GWh 3% 0.81 GWh 2%
Wind
Mini hydro
Power Stations in Sri Lanka - 2017
Hydro 1391.4 MW
Wind 131.5 MW
• Intake
This may consist of canals, flumes, pipelines and pressure tunnels. Mostly made out of
concrete and has a small gradient. Purpose is to carry the water form reservoir to penstock.
Increase in Wicked gates Pressure drops inside Water level falls in the
load opened Penstock surge tank
Decrease in Wicked gates Pressureincreases Water level rises in the
load closed inside Penstock surge tank
Elements of a hydro electrical power plant
• Penstock
It is a closed conduit with a high gradient which connects the surge tank to the scroll case of
the turbine. Penstocks are built of steel or reinforced concrete and thickness is decided according to
the maximum hydrostaticpressure which can occur.
Tail race
Tail race leads the discharged water flow from the turbine to the outside of the power
plant.
Elements of a hydro electrical power plant
• Water turbines/ Prime Movers
• In hydro power plants, water turbines are used as prime movers. Mainly
there are three types of water turbines.
• Kaplan turbine: Used for low head(<50m), large flow plants. Blade angel can be changed
according to the head (e.g.: Udawalawa)
• Francis turbine : Used for low and medium head plants (50m<h<400m) e.g.: Randengala,
• Rantambe
• Pelton Wheel: Used for high head (>500m), low flow plants. E.g.: New Laxapana
HYDRO ELECTRICAL POWER PLANT
Intake
Basic Types of Hydro electric power plants
1. Storage Type
2. Pumped Storage type
3. Run off river type
1. Storage Type
This is the most common hydro power plant type in Sri Lanka. Water is stored
in wet season and use to generate electricity when needed in dry season. So
these kinds of plants are often coupled with irrigation systems.
Hydro electric
power plants
The water in the tail water pond is pumped up to the head water pond during
the off peak hours. And that water is used to generate electricity during the
peak hours. Mostly used in countries like Japan which has limited hydro
resources.
• 𝑃 = 𝑄𝜌𝑔𝐻𝑛 ŋ𝑇ŋ𝐺
• P- Output power
• Q – Water flow rate
ηT - Turbine efficiency
ηG – Generator efficiency
• Advantages of hydro power
• No fuel cost.
• Long life time.
• Efficiency does not fall with time
• Low operational and maintenance cost
• Can be run up and synchronized in few minutes
• Rapidly changing load demands can be met easily (dispatchable).
• Very minimum impact on environment (no smoke or ash produced).
• Can be used to serve purposes like irrigation and flood water control.