Power Stations based on source
Fuels :– Solid fuels
– Liquid fuels
– Gaseous fuels
Water :- Hydro power station
Nuclear power :- Atomic power station
Wind power :- Wind mills
Advantages of Hydro power
Once the dam is built, the energy is virtually free
A clean source of renewable energy
Has the capacity to provide base and peak-load
Has the capacity to follow demand fluctuations almost
Offers a quick response to failings in power grids
No waste or pollution produced
Much more reliable than wind, solar or wave power
Disadvantages of Hydro power
The dams are very expensive to build
Building a large dam will flood a very large area
upstream, causing problems for animals that used to live
Finding a suitable site can be difficult - the impact on
residents and the environment may be unacceptable
Water quality and quantity downstream can be affected,
which can have an impact on plant life.
How Hydropower Works!
How Hydropower Works! (ctd…)
Water from the
reservoir flows due to
gravity to drive the
Turbine is connected to
Power generated is
transmitted over power
THEORETICAL- The maximum potential that exists.
TECHNICAL- It takes into account the cost involved
in exploiting a source (including the environmental
and engineering restrictions)
ECONOMIC- Calculated after detailed
environmental, geological, and other economic
Theoretical potential is about 40,500 TWh per year.
The technical potential is about 14,300 TWh per year.
The economic potential is about 8100 TWh per year.
The world installed hydro capacity currently stands at 694
In the 1980s the percentage of contribution by
hydroelectric power was about 8 to 9%.
Currently the percentage of contribution by hydroelectric
power is close to 20% of the total energy generation.
Global Installed Capacity
The Indian Scenario
potential is about 84000 MW at 60% load
factor spread across six major basins in the
Pumped storage sites have been found recently
which leads to a further addition of a maximum of
The possible installed capacity is around 150000
MW (Based on the report submitted by CEA to
the Ministry of Power)
India’s Basin wise potential
Potential at 60%LF (MW)
Probable installed capacity (MW)
Central Indian rivers
Arch shape gives strength
Less material (cheaper)
Need strong foundation
Concrete Gravity Dams
Weight holds dam in
place that increase
Resist sliding and
Lots of concrete
Face is held up by a
series of supports
Flat or curved face
Water tight dam
During Storage, water
pumped from lower
reservoir to higher one.
Water released back to
lower reservoir to
Operation : Two pools of
Upper pool – impoundment
Lower pool – natural lake,
river or storage reservoir
– Production of peak
– Can be built anywhere
with reliable supply of
The Raccoon Mountain project
Sizes of Hydropower Plants
Large plants : capacity >30 MW
Small Plants : capacity b/w 100 kW to 30 MW
Micro Plants : capacity up to 100 kW
Large Scale Hydropower plant
Small Scale Hydropower Plant
Micro Hydropower Plant
Micro Hydropower Systems
Many creeks and rivers are permanent, i.e., they never dry
up, and these are the most suitable for micro-hydro power
Micro hydro turbine could be a waterwheel
Newer turbines : Pelton wheel (most common)
Others : Turgo, Crossflow and various axial flow turbines
Uses the velocity of the water to move the runner and
discharges to atmospheric pressure.
The water stream hits each bucket on the runner.
No suction downside, water flows out through turbine
housing after hitting.
High head, low flow applications.
Types : Pelton wheel, Cross Flow
Nozzles direct forceful
streams of water against a
series of spoon-shaped
buckets mounted around
the edge of a wheel.
Each bucket reverses the
flow of water and this
impulse spins the turbine.
Pelton Wheels (continued…)
Suited for high head, low
The largest units can be
up to 200 MW.
Can operate with heads as
small as 15 meters and as
high as 1,800 meters.
Cross Flow Turbines
elongated, rectangularsection nozzle directed
against curved vanes on a
“squirrel cage” blower
water flows through the
Cross Flow Turbines (continued…)
pass : water flows from the outside of the
blades to the inside
Second pass : from the inside back out
Larger water flows and lower heads than the
action of pressure and moving water.
Runner placed directly in the water stream
flowing over the blades rather than striking each
lower head and higher flows than compared with
the impulse turbines.
Propeller Hydropower Turbine
Runner with three to six blades.
Water contacts all of the blades
Through the pipe, the pressure
Pitch of the blades - fixed or
Scroll case, wicket gates, and a
Types: Bulb turbine, Straflo,
Tube turbine, Kaplan
The turbine and
generator are a sealed
unit placed directly in
the water stream.
Straflo : The generator is attached directly to the
perimeter of the turbine.
Tube Turbine : The penstock bends just before or after the
runner, allowing a straight line connection to the generator
Kaplan : Both the blades and the wicket gates are
adjustable, allowing for a wider range of operation
The inlet is a scroll-shaped
tube that wraps around the
turbine's wicket gate.
Water is directed tangentially,
through the wicket gate, and
spirals on to a propeller shaped
runner, causing it to spin.
The outlet is a specially shaped
draft tube that helps decelerate
the water and recover kinetic
The inlet is spiral shaped.
Guide vanes direct the water
tangentially to the runner.
This radial flow acts on the
runner vanes, causing the
runner to spin.
The guide vanes (or wicket
gate) may be adjustable to
allow efficient turbine
operation for a range of water
Francis Turbines (continued…)
Best suited for sites with
high flows and low to
Efficiency of 90%.
expensive to design,
manufacture and install,
but operate for decades.
Kinetic Energy Turbines
Also called free-flow turbines.
Kinetic energy of flowing water used rather than potential
from the head.
Operate in rivers, man-made channels, tidal waters, or
Do not require the diversion of water.
Kinetic systems do not require large civil works.
Can use existing structures such as bridges, tailraces and
Hydroelectric Power Plants in India
Environmental impacts of Hydro
• No operational greenhouse gas emissions
• Savings (kg of CO2 per MWh of electricity):
– Coal 1000 kg
– Oil 800 kg
– Gas 400 kg
• No SO2 or NOX
– flood control, irrigation, transportation, fisheries and
The loss of land under the reservoir.
Interference with the transport of sediment by the dam.
Problems associated with the reservoir.
– seismic effects.
Loss of land
A large area is taken up in the form of a reservoir in case
of large dams
This leads to reduction in fertile rich soil in the flood
plains, forests and even mineral deposits
Power per area ratio is evaluated to quantify this impact
Usually ratios lesser than 5 KW per hectare implies that
the plant needs more land area than competing renewable
Interference with Sediment transport
Rivers carry a lot of sediments.
Creation of a dam results in the deposition of sediments on
the bottom of the reservoir.
Land erosion on the edges of the reservoir due to
deforestation also leads to deposition of sediments.
Climatic and Seismic effects
It is believed that large reservoirs induce have the
potential to induce earthquakes.
In tropics, existence of man-made lakes decreases the
convective activity and reduces cloud cover. In temperate
regions, fog forms over the lake and along the shores
when the temperature falls to zero and thus increases
humidity in the nearby area.
Some major/minor induced earthquakes
Many fishes require flowing water for reproduction and
cannot adapt to stagnant resulting in the reduction in its
Heating of the reservoirs may lead to decrease in the
dissolved oxygen levels.
Other water-borne diseases like malaria, river-blindness
Methods to alleviate the negative impact
Creation of ecological reserves.
Limiting dam construction to allow substantial free
Building sluice gates and passes that help prevent fishes
ECONOMICS OF HYDRO POWER
Local HP Economics
Development, operating, and maintenance costs, and electricity
First check if site is developed or not.
If a dam does not exist, several things to consider are: land/land
rights, structures and improvements, equipment, reservoirs, dams,
waterways, roads, railroads, and bridges.
Development costs include recreation, preserving historical and
archeological sites, maintaining water quality, protecting fish and
costs are highly site specific
Dams are very expensive
Civil works form two-thirds of total cost
– Varies 25 to 80%
Large Western schemes: $ 1200/kW
Developing nations: $ 800 to $ 2000/kW
Compare with CCGT: $ 600 to $800/kW
with fossil-fuelled plant
– No fuel costs
– Low O&M cost
– Long lifetime
Sardar Sarovar Dam
Project planning started as
early as 1946.
Project still under
construction with a part of
the dam in operation.
A concrete gravity dam,
1210 meters (3970 feet) in
length and with a maximum
height of 163 meters
The gross storage capacity of the reservoir is 0.95 M.
ha.m. (7.7 MAF) while live storage capacity is 0.58
M.ha.m. (4.75 MAF).
The total project cost was estimated at Rs. 49 billion at
1987 price levels.
There are two power houses project- 1200 MW River Bed
Power House and 250 MW Canal Head Power House.
Power benefits are shared among Madhya Pradesh,
Maharashtra and Gujarat in the ratio of 57:27:16
Environmental Protection measures
About 14000 ha of land has been afforested to compensate
for the submergence of 4523 ha of land.
Formation of co-operatives, extensive training to the
fisherman, providing infrastructure such as fish landing
sites, cold storage and transportation etc.
Surveillance & Control of Water related diseases and
Rehabilitation & Resettlement
Individual benefits like grant of minimum 2 ha. of land for
agricultural purpose of the size equal to the area of land
Civil and other amenities such as approach road, internal
roads, primary school building, health, centre, Panchayat
ghar, Seeds store, Children's park, Village pond, Drinking
water wells, platform for community meetings, Street
light electrification, Religious place, Crematorium ground
etc. are provided at resettled site.