Hydropower harnesses the kinetic energy of moving water to generate electricity. It has been used for centuries to power mills and factories. Modern hydropower plants first emerged in the late 19th century and have since become a major source of renewable energy worldwide. Hydropower is classified based on factors like plant size and head. Key components include dams, reservoirs, penstocks, turbines, generators, and transformers. While hydropower has significant advantages as a clean energy source, new plants also face environmental challenges and changing water availability due to climate change. Many regions still have potential to expand sustainable hydropower development in the future.

1. Hydropower

2. WHAT IS HYDROPOWER
• Hydropower is the electricity or power that is generated from the
energy of moving water. Hydro means “water.”
• It is a renewable source of energy. It is constantly being refilled by the
water cycle, specifically precipitation.

3. HISTORY OF HYDROPOWER
• Ancient Greek farmers have used water wheels to grind wheat into flour.
• In the early 1800’s, American and European factories made use of the
water wheel to run machines.
• In the late 19th century, hydropower was used for generating electricity.
• Waterwheels and mills were used for irrigation and mining.
• Hydropower was the foremost source of energy for new inventions

4. HISTORY OF HYDROPOWER
• In the 1830’s, hydropower provided the energy for transportation up and
down steep hills.
• In 1848, the turbine was created, improving the waterwheels and mills
which were bulky and slow. Turbines are specific to each site.
• The first hydroelectric power plant was built at the Niagara Falls in 1879.
• In the late 1940’s, big dams for hydropower had been built.

5. CLASSIFICATION OF HYDROPOWER PLANTS :
Classification of hydropower plants
According to
Capacity
Large
Medium
Small
Mini
Micro
Pico
According to
head
High
Medium
Low
According to
purpose
Single purpose
Multi purpose
According to
facility types
Run-of-River
Reservoirs
In-stream
Pumped
storage
According to
hydrological
relation
Single
Cascade
According to
transmission
system
Isolated
Connected to
grid

6. LARGE: >100 MW
MEDIUM: 25 – 100 MW
SMALL: 1-25 MW
MINI: 100 KW - 1MW
MICRO: 5 – 100 KW
PICO: < 5 KW

7. LOW HEAD:
Low head hydro power applications use river current or tidal flows of 30 meters or less to produce energy.
These applications do not need to dam or retain water to create hydraulic head, the head is only a few
meters.
Using the current of a river or the naturally occurring tidal flow to create electricity may provide a
renewable energy source that will have a minimal impact on the environment.
Figure-sectional view of low head hydropower plant

8. MEDIUM HEAD:
A power station operating under heads from
30m to 300m.
Figure- sectional view of medium head hydropower plant

9. HIGH HEAD:
A power station operating under heads above about 300m.
A head of 200m/250m is considered as the limit between medium and high head power
stations.
Figure- high head hydropower plant

10. Figure-(a) single stage hydropower development scheme
(b) cascade or multistage hydropower system
SINGLE STAGE-
When the run off from a single hydropower
plant is diverted back into river or for any other
purpose other than power generation, the setup
is known as Single Stage.
CASCADE SYSTEM-
When two or more hydropower plants are
used in series such that the run off discharge of
one hydro power plant is used as the is a intake
discharge of the second hydro power plant such
a system is known as CASCADE hydropower
plant.

11. SINGLE PURPOSE: When the whole soul purpose of a project is
to produce electricity then such a project is known as a Single
Purpose Hydro Power Project.
MULTIPURPOSE : When the water used in hydropower project is
to be used for other purposes like irrigation, flood control or
fisheries then such a project is known as Multi Purpose Hydro
Power Project.

12. These are hydro power plants that utilize the stream flow as it comes ,
without any storage being provided.
RUN-OF-RIVER TYPE
Figure-Run-of-River hydropower plant
Hydropower plants can be classified in three categories according to
operation and type of flow

13. Hydropower plants with storage are supplied with water from large storage reservoir
that have been
developed by constructing dams across rivers.
 Assured flow for hydro power generation is more certain for the storage schemes than
the run-of-river schemes.
STORAGE (RESERVOIR) TYPE
Figure-pumped storage hydropower plant

14. PUMPED STORAGE TYPE
Figure-pumped storage hydropower plant
 Pumped storage type hydropower plants are those which utilize the flow of water
from a reservoir at higher potential to one at lower potential.
During off-peak hours, the reversible units are supplied with the excess electricity
available in the power grid which then pumps part of the water of the tail-water
pond back into the head-water pond.

15. IN-STREAM
When the velocity of water i.e kinetic
energy flowing in the stream is used
for conversion into electrical power,
then the system is known as In-stream.
Photograph of In-stream hydro power system

16. ISOLATED: Whenever a hydropower plant is set up in a remote area in
order to meet the local demands then such a hydropower plant is known as
Isolated System.
CONNECTED TO GRID: Whenever the hydropower plant is set up to
meet the demands of areas which are at a fair distance from the plant, then the
transmission of power takes through the grid system. Such a setup is referred
to as Connected to grid.

17. COMPONENTS
1. Dam and Reservoir
2. Spillway
3. Penstock
4. Turbine
5. Generator ,Transformer
7-power lines

18. DAM AND RESERVOIR
An open-air storage area usually formed by masonry or earthwork where water is
collected and kept in quantity so that it may be drawn off for use.
The water reservoir is the place behind the dam where water is stored.
The water in the reservoir is located higher than the rest of the dam structure.
The height of water in the reservoir decides how much potential energy
the water
The higher the height of water, the more its potential energy.
The high position of water in the reservoir also enables it to move
downwards effortlessly.

19.  These are the gates built on the inside of the dam. The water from
reservoir is released and controlled through these gates.
 These are called inlet gates because water enters the power
generation unit through these gates.
 When the control gates are opened the water flows due to gravity
through the penstock and towards the turbines.
 The water flowing through the gates possesses potential as well as
kinetic energy.

20. PENSTOCK
 The penstock is the long pipe or the shaft
that carries the water flowing from the reservoir
towards the power generation unit, comprised of
the turbines and generator. The water in the
penstock possesses kinetic energy due to its
motion and potential energy due to its height.

21. Hydro Turbines is a rotary machine that converts kinetic and
potential energy of water into mechanical work.
Turbine :

22. Pelton Wheel Turbine:
This type Turbine is used for high Head and low
Discharge (Head above 180 meters.)
Francis turbine (used at RBPH):
This type turbine is used for medium head and
medium discharge (head 40 to 400 meters.)
Kaplan Turbine
(used at CHPH): This type Turbine is used for low
Head and high Discharge (Head 40 to 60 Meters.)
Types of Turbine used :

23. Generator ,Transformer
• As the water rushes through the turbine, it spins the
turbine shaft, which is coupled to the electric
generator. The generator has a rotating
electromagnet called a rotor and a stationary part
called a stator. The rotor creates a magnetic field
that produces an electric charge in the stator. The
charge is transmitted as electricity.
The step-up transformer increases the voltage of
the current coming from the stator.

36. SITE SELECTION FOR HYDROPOWER PLANTS
• Water Storage
for water Availability of Water:
Run-off data for many years availability throughout the year
• Head of Water
most economic head, possibility of constructing a dam to get required head
• Geological Investigations
strong foundation, earthquake frequency is less
• Water Pollution
excessive corrosion and damage to metallic structures

37. SITE SELECTION FOR HYDROPOWER PLANTS
• Social and Environmental Effects
submergence of areas, effect on biodiversity (e.g. western ghat), cultural and historic aspects
• Access to Site for transportation of construction material and heavy machinery new
railway lines or roads may be needed
• Multipurpose:
power generation, irrigation, flood control, navigation, recreation; because initial cost of power
plant is high because of civil engineering construction work

38. • Water is a renewable energy source.
• Maintenance and operation charges are very low.
• The efficiency of the plant does not change with age.
• In addition to power generation, hydro-electric power plants are also useful for
flood control, irrigation purposes, fishery and recreation.
• Have a longer life(100 to 125 years) as they operate at atmospheric temperature.
• Water stored in the hydro-electric power plants can also be used for domestic
water supply.
• Since hydro-electric power plants run at low speeds(300 to 400 rpm) there is no
requirement of special alloy steel construction materials or specialised
mechanical maintenance.
• Advantages of hydro power plant :

39. • The initial cost of the plant is very high.
• Since they are located far away from the load centre, cost of
transmission lines and transmission losses will be more.
• During drought season the power production may be reduced or
even stopped due to insufficient water in the reservoir.
• Water in the reservoir is lost by evaporation.
• Disadvantages of hydro power plant :

40. FUTURE OF HYDROPOWER
Africa’s hydropower future
Energy poverty is rife in Africa. Of the more than one billion
people living in its 54 countries, over half lack access to
electricity.

41. In global debates on renewable energy and the drive to find cleaner, greener alternatives t
fossil fuels, wind and solar power usually grab the headlines.

42. But the data shows a different picture. Hydropower produces more than
three-quarters of the world’s renewable energy output each year. And its
carbon emissions — over the entire lifecycle of construction, operation and
decommissioning — are often far lower than those from all other
renewable sources, including wind and solar.
Across Africa, hydropower is responsible for 84 per cent of all non-fossil
fuel energy use. But in a continent rich in lakes and rivers, the
opportunities for expanding hydropower are huge.

43. THE NILE IS THE WORLD’S LONGEST RIVER, MAKING IT ONE OF AFRICA’S GREATEST
POTENTIAL SOURCES OF HYDROPOWER.

45. THE GERD IS BEING BUILT IN THE BENISHANGUL-GUMUZ REGION OF ETHIOPIA, JUST
UPSTREAM FROM THE SUDANESE BORDER. ON COMPLETION IN 2017, IT IS PLANNED TO
BE 145 METRES HIGH — NEARLY ONE-AND-A-HALF TIMES THE HEIGHT OF VICTORIA FALLS
— MAKING IT THE HIGHEST DAM IN AFRICA. ITS RESERVOIR IS SET TO CONTAIN 74 BILLION
CUBIC METRES OF WATER, ROUGHLY THE SAME AS 13 TIMES ETHIOPIA’S TOTAL ANNUAL
WATER CONSUMPTION. THE ETHIOPIAN GOVERNMENT EXPECTS THE DAM TO PRODUCE
SIX GIGAWATTS OF ENERGY AT PEAK OUTPUT. THIS WILL ALMOST TRIPLE ETHIOPIA’S
ELECTRICITY PRODUCTION, WHICH CURRENTLY STANDS AT LESS THAN THREE GIGAWATTS.
HYDROPOWER PROJECTS OFTEN SPLIT OPINION. THEY CAN PROVIDE ABUNDANT CLEAN
ENERGY FOR AROUND 50 YEARS WITHOUT MAJOR MAINTENANCE AND, UNLIKE OTHER
RENEWABLES SUCH AS SOLAR OR WIND, THEY PRODUCE CONTINUOUS POWER.

49. Future European hydro power
Global
potential for
small-scale
hydro power
Pumping
power
increases
system
reliability