hydro power

How Hydropower Works!
 Hydrologic cycle

How Hydropower Works! (ctd…)
 Water from the
reservoir flows due to
gravity to drive the
turbine.
 Turbine is connected to
a generator.
 Power generated is
transmitted over power
lines.

Potential
 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
constraints.

REGION THEORETICAL
POTENTIAL (TWh)
TECHNICAL
POTENTIAL (TWh)
AFRICA 10118 3140
N. AMERICA 6150 3120
LATIN AMERICA 5670 3780
ASIA 20486 7530
OCEANIA 1500 390
EUROPE 4360 1430
WORLD 44280 19390
Continent Wide distribution

COUNTRY POWER
CAPACITY
(GWh)
INSTALLED
CAPACITY
(GW)
TAJIKISTAN 527000 4000
CANADA 341312 66954
USA 319484 79511
BRAZIL 285603 57517
CHINA 204300 65000
RUSSIA 160500 44000
NORWAY 121824 27528
JAPAN 84500 27229
INDIA 82237 22083
FRANCE 77500 77500
Top ten countries (in terms of capacity)

UNDP estimates
 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
GW.
 In the 1980s the percentage of contribution by
hydroelectric power was about 8 to 9%.
 The total power generation in 2000 was 2675 Billion
KWh or close to 20% of the total energy generation.

Continued…
 Most of the undeveloped potential lies in the erstwhile
USSR and the developing countries.
 Worldwide about 125 GW of power is under construction.
 The largest project under construction is the Three Gorges
at the Yangtze river in China. Proposed potential is 18.2
GW and the proposed power output is 85 TWh per year.

The Indian Scenario
 The potential is about 84000 MW at 60% load factor
spread across six major basins in the country.
 Pumped storage sites have been found recently which
leads to a further addition of a maximum of 94000 MW.
 Annual yield is assessed to be about 420 billion units per
year though with seasonal energy the value crosses600
billion mark.
 The possible installed capacity is around 150000 MW
(Based on the report submitted by CEA to the Ministry of
Power)

Continued …
 The proportion of hydro power increased from 35% from
the first five year plan to 46% in the third five year plan
but has since then decreased continuously to 25% in 2001.
 The theoretical potential of small hydro power is 10071
MW.
 Currently about 17% of the potential is being harnessed
 About 6.3% is still under construction.

India’s Basin wise potential
Rivers Potential at 60%LF (MW) Probable installed capacity (MW)
Indus 19988 33832
Ganga 10715 20711
Central Indian rivers 2740 4152
West flowing 6149 9430
East flowing 9532 14511
Brahmaputra 34920 66065
Total 84044 148701

Region wise status of hydro development
REGION POTENTIAL
ASSESSED
(60% LF)
POTENTIAL
DEVELOPED
(MW)
%
DEVELOPED
UNDER
DEVELOPMENT
NORTH 30155 4591 15.2 2514
WEST 5679 1858 32.7 1501
SOUTH 10763 5797 53.9 632
EAST 5590 1369 24.5 339
NORTH
EAST
31857 389 1.2 310
INDIA 84044 14003 16.7 5294

Major Hydropower generating units
NAME STATA CAPACITY (MW)
BHAKRA PUNJAB 1100
NAGARJUNA ANDHRA PRADESH 960
KOYNA MAHARASHTRA 920
DEHAR HIMACHAL PRADESH 990
SHARAVATHY KARNATAKA 891
KALINADI KARNATAKA 810
SRISAILAM ANDHRA PRADESH 770

Installed Capacity
REGION HYDRO THERMAL WIND NUCLEAR TOTAL
NORTH 8331.57 17806.99 4.25 1320 27462.81
WEST 4307.13 25653.98 346.59 760 31067.7
SOUTH 9369.64 14116.78 917.53 780 25183.95
EAST 2453.51 13614.58 1.10 0 16069.19
N.EAST 679.93 1122.32 0.16 0 1802.41
INDIA 25141.78 72358.67 1269.63 2860 101630.08

Region wise contribution of Hydropower
REGION PERCENTAGE
NORTH 30.34
WEST 13.86
SOUTH 37.2
EAST 15.27
NORTH-EAST 37.72
INDIA 24.74

Annual gross generation (GWh)
YEAR GROSS GENERATION
85/86 51021
90/91 71641
91/92 72757
92/93 69869
93/94 70643
94/95 82712
95/96 72579
96/97 68901
97/98 74582
98/99 82690
99/2000 80533
00/01 74346

Annual Gross Generation (GWh)
60000
65000
70000
75000
80000
85000
1991 1993 1995 1997 1999 2001
Year
Electricity
Generated
(GWh)

Potential of Small Hydropower
 Total estimated potential of 180000 MW.
 Total potential developed in the late 1990s was about
47000 MW with China contributing as much as one-third
total potentials.
 570 TWh per year from plants less than 2 MW capacity.
 The technical potential of micro, mini and small hydro in
India is placed at 6800 MW.

Small Hydro in India
STATE TOTAL CAPACITY (MW)
ARUNACHAL PRADESH 1059.03
HIMACHAL PRADESH 1624.78
UTTAR PRADESH & UTTARANCHAL 1472.93
JAMMU & KASHMIR 1207.27
KARNATAKA 652.51
MAHARASHTRA 599.47

Sites (up to 3 MW) identified by UNDP
STATE TOTAL SITES CAPACITY
NORTH 562 370
EAST 164 175
NORTH EAST 640 465
TOTAL 1366 1010

Small Hydro in other countries
 China has 43000 small hydro-electric power stations
nationwide to produce 23 million KWh a year. It has 100
million kilowatts of explorable small hydro-electric power
resources in mountainous areas of which only 29% has
been tapped.
 Philippines has a total identified mini-hydropower
resource potential is about 1132.476 megawatts (MW) of
which only 7.2% has been utilized.
 There is about 3000 MW of small hydro capacity in
operation in the USA. A further 40 MW is planned.

Technology
Hydropower
Technology
Impoundment Diversion
Pumped
Storage

Dam Types
 Arch
 Gravity
 Buttress
 Embankment or Earth

Arch Dams
 Arch shape gives
strength
 Less material (cheaper)
 Narrow sites
 Need strong abutments

Concrete Gravity Dams
 Weight holds dam in
place
 Lots of concrete
(expensive)

Buttress Dams
 Face is held up by a
series of supports
 Flat or curved face

Embankment Dams
 Earth or rock
 Weight resists flow
of water

Diversion Facility
 Doesn’t require dam
 Facility channels portion
of river through canal or
penstock

Pumped Storage
 During Storage, water
pumped from lower
reservoir to higher one.
 Water released back to
lower reservoir to
generate electricity.

Pumped Storage
 Operation : Two pools of Water
 Upper pool – impoundment
 Lower pool – natural lake, river
or storage reservoir
 Advantages :
– Production of peak power
– Can be built anywhere with
reliable supply of water
The Raccoon Mountain project

Sizes of Hydropower Plants
 Definitions may vary.
 Large plants : capacity >30 MW
 Small Plants : capacity b/w 100 kW to 30 MW
 Micro Plants : capacity up to 100 kW

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
production
 Micro hydro turbine could be a waterwheel
 Newer turbines : Pelton wheel (most common)
 Others : Turgo, Crossflow and various axial flow turbines

Generating Technologies
 Types of Hydro Turbines:
– Impulse turbines
 Pelton Wheel
 Cross Flow Turbines
– Reaction turbines
 Propeller Turbines : Bulb turbine, Straflo, Tube Turbine,
Kaplan Turbine
 Francis Turbines
 Kinetic Turbines

Impulse 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

Pelton Wheels
 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
flow sites.
 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
 drum-shaped
 elongated, rectangular-
section nozzle directed
against curved vanes on a
cylindrically shaped
runner
 “squirrel cage” blower
 water flows through the
blades twice

Cross Flow Turbines (continued…)
 First 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
Pelton.

Reaction Turbines
 Combined action of pressure and moving water.
 Runner placed directly in the water stream
flowing over the blades rather than striking each
individually.
 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
constantly.
 Through the pipe, the pressure
is constant
 Pitch of the blades - fixed or
adjustable
 Scroll case, wicket gates, and a
draft tube
 Types: Bulb turbine, Straflo,
Tube turbine, Kaplan

Bulb Turbine
 The turbine and
generator are a sealed
unit placed directly in
the water stream.

Others…
 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

Kaplan Turbine
 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
energy.

Francis Turbines
 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
flow conditions.

Francis Turbines (continued…)
 Best suited for sites with
high flows and low to
medium head.
 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
ocean currents.
 Do not require the diversion of water.
 Kinetic systems do not require large civil works.
 Can use existing structures such as bridges, tailraces and
channels.

Hydroelectric Power Plants in India
Baspa II Binwa

Continued …
Gaj Nathpa Jakri

Continued…
Rangit Sardar Sarovar

Benefits…
 Environmental Benefits 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
 Non-environmental benefits
– flood control, irrigation, transportation, fisheries and
– tourism.

Disadvantages
 The loss of land under the reservoir.
 Interference with the transport of sediment by the dam.
 Problems associated with the reservoir.
– Climatic and seismic effects.
– Impact on aquatic ecosystems, flora and fauna.

Loss of land
 A large area is taken up in the form of a reservoir in case
of large dams.
 This leads to inundation of fertile alluvial rich soil in the
flood plains, forests and even mineral deposits and the
potential drowning of archeological sites.
 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
resources. However this is only an empirical relation.

 Disappropriating and resettlement represents a mammoth
political and management challenge. Related costs can increase
project costs by as much as 10% if planned poorly.
HYDROPLANT COUNTRY POPULATION
DISPLACED
Danjiangkou China 383000
Aswan Egypt 120000
Volta Ghana 78000
Narmada Sardar
Sarovar
India 70000
Three Gorges China 2000000

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.
RIVER Kg/m3
Yellow River 37.6
Colorado 16.6
Amur 2.3
Nile 1.6

Effects
 Capture of sediment decreases the fertility downstream
as a long term effect.
 It also leads to deprivation of sand to beaches in coastal
areas.
 If the water is diverted out of the basin, there might be
salt water intrusion into the inland from the ocean, as the
previous balance between this salt water and upstream
fresh water in altered.
 It may lead to changes in the ecology of the estuary area
and lead to decrease in agricultural productivity.

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
DAM NAME COUNTRY HEIGHT (m) VOLUME OF
RESERVOIR
(m3)
MAGNITUDE
KOYNA INDIA 103 2780 6.5
KREMASTA GREECE 165 4650 6.3
HSINFENGKIANG CHINA 105 10500 6.1
BENMORE NEW
ZEALAND
118 2100 5.0
MONTEYNARD FRANCE 155 240 4.9

Eutrophication
 In tropical regions due to decomposition of the vegetation,
there is increased demand for biological oxygen in the
reservoir.
 The relatively constant temperatures inhibit the thermally
induced mixing that occurs in temperate latitudes.
 In this anaerobic layer, there is formation of methane
which is a potential green house gas.
 This water, when released kills the fishes downstream and
creates an unattractive odor. The only advantage is that all
these activities are not permanent.

Other problems
 Many fishes require flowing water for reproduction and
cannot adapt to stagnant resulting in the reduction in its
population.
 Heating of the reservoirs may lead to decrease in the
dissolved oxygen levels.
 The point of confluence of fresh water with salt water is a
breeding ground for several aquatic life forms. The reduction
in run-off to the sea results in reduction in their life forms.
 Other water-borne diseases like malaria, river-blindness
become prevalent.

Methods to alleviate the negative impact
 Creation of ecological reserves.
 Limiting dam construction to allow substantial free
flowing water.
 Building sluice gates and passes that help prevent fishes
getting trapped.

Case Study- Volta Lake, Ghana
 Volta lake was formed as a result of the construction of
the Akosombo Dam.
 It was aimed at providing much needed power needs for
domestic consumption and for the production of
Aluminium.
 Even though much study was conducted prior to the
construction, many favorable and adverse environmental
changes took place.

Favorable impact
 Enhanced fishing upstream.
 Opportunities for irrigated farming downstream.
 With the flooding of the forest habitat of the Tsetse fly,
the vector of this disease, the problem of Sleeping
Sickness has been substantially reduced.

Negative Impact
 Diminished fishing downstream.
 Growth of long lasting weeds like Pistia, Vossia spp.
Ceratophyllum.
 Ceratophyllum’s submerged beds house large populations
of Bulinus snails the vector of Schistosomiasis.
 Growth of dangerous water weeds like water hyacinth.
 Prevalence of river blindness (Snchocerchiasis),
bilharzia (Schistosomiasis), malaria and Sleeping
Sickness (Trypanosomiasis

Technological advancements
 Technology to mitigate the negative environmental
impact.
– Construction of fish ways for the passage of fish
through, over, or around the project works of a hydro
power project, such as fish ladders, fish locks, fish lifts
and elevators, and similar physical contrivances
– Building of screens, barriers, and similar devices that
operate to guide fish to a fish way

Continued…
 Evaluating a new generation of large turbines
– Capable of balancing environmental, technical,
operational, and cost considerations
 Developing and demonstrating new tools
– to generate more electricity with less water and greater
environmental benefits
– tools to improve how available water is used within
hydropower units, plants, and river systems
 Studying the benefits, costs, and overall effectiveness of
environmental mitigation practices

Global HP Economics
 Cost of HP is affected by oil prices; when oil prices are
low, the demand for HP is low.
 Thesis was tested in the 1970s when the oil embargo was
in place
 More plants built, greater demand for HP
 Reduces dependency on other countries for conventional
fuels

Local HP Economics
 Development, operating, and maintenance costs, and electricity
generation
 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
wildlife.

Construction Costs
 Hydro 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

Production Costs
 Compared with fossil-fuelled plant
– No fuel costs
– Low O&M cost
– Long lifetime

Parameters
 Payback-HP has higher payback time(25
years)
 Net present value (NPV)
 Unit cost
 Discounting

Effect of discounting payback: CCGT

Discounting and NPV
 Effect of discounting
– Hydro’s high capital cost at near full value
– Its additional revenue far in future less
valuable
– CCGT has higher NPV

Unit cost
 Unit cost
– Cost per kWh produced
– Discount costs and production
 HP has greater cost
– 2 to 7 p/kWh typical range for HP
– 1.5 to 2.5 p/kWh for CCGT

Conclusion
 Overall CCGT appears to be the better
investment
 Environmental or operational benefits not
considered
 Overall HP is still a better investment for
future

Small HP costs
 Machinery-includes turbine, gearbox or drive
belts, generator, water inlet control valve.
 Civil Works-includes intake and screen to
collect the water, the pipeline or channel,
turbine house and machinery foundations,
and the channel to return the water back to
the river-site specific

Small HP costs
 Electrical Works-control panel and control
system, wiring.
 External Costs-includes the services of
someone to design the installation, costs of
obtaining a water license, planning costs and
cost of connection to the electricity network
-these two depend on maximum power output

Typical costs of 100KW plant
Low head High head
£1000s £1000s
Machinery 30 - 90 15 - 60
Civil works 10 - 40 20 - 40
Electrical works 10 - 20 10 - 20
External (no grid connection) 8 - 15 8 - 15
________________ ________________
Total: 58 - 165 53 - 135

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
respectively.

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
communicable diseases.
 Extension of Shoolpaneshwar sanctuary to cover an area
of 607 sq.km.

Rehabilitation & Resettlement
 Individual benefits like grant of minimum 2 ha. of land for
agricultural purpose of the size equal to the area of land
acquired.
 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.

The Three Gorges Project
 Being built on the
Yangtze river.
 Still under construction to
supply energy and provide
inland transportation.
 Project expected to
complete in 2009.

Some Facts….
 Dam to provide 18.2 GW of power using 26 Francis
generators of 700 MW each.
 630 Km long and 1.3 Km wide capable of allowing
10,000-ton ocean-going freighters to sail directly into the
nation's interior for six months of each year.
 More than 2 million people are to be resettled.
 The amount of concrete totals 26.43 million cubic meters,
twice that of the Itaipu project in Brazil, currently the
world's largest hydroelectric dam.

Environmental and Other Concerns
 There have been little to no attempts made toward
removing accumulations of toxic materials and other
potential pollutants from industrial sites that will be
inundated. They number more than 1600 in all.
 The dam will disrupt heavy silt flows in the river. It could
cause rapid silt build-up in the reservoir, creating an
imbalance upstream, and depriving agricultural land and
fish downstream of essential nutrients. However,
sufficient studies have not been conducted.

 Potential Hazard also exists. For example, In an annual
report [1] to the United States Congress, the Department
of Defense cited that Taiwanese "proponents of strikes
against the mainland apparently hope that merely
presenting credible threats to China's urban population or
high-value targets, such as the Three Gorges Dam, will
deter Chinese military coercion."

 Independent reports suggest residents are convinced their
compensation is miserly even though China claims its
plans will improve the life of those affected.
 Archaeologists and historians have estimated nearly 1,300
important sites will disappear under the reservoir's waters
including remnants of the homeland of the Ba civilization.

hydro power

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