2. HYDROPOWER, the Leading Renewable Energy
• Water energy encompasses both plants installed on land — on
rivers and lakes — and ocean energy, which is still being
developed and harnesses the force of waves, tides and
currents. Widely used for decades, hydropower plants are the
world’s leading renewable energy source, producing 83%
renewable power.
Three Gorges Dam Itaipu Dam Xiluodu Dam
4. • The kinetic energy generated by moving water has been used by
humankind for centuries, to drive watermills that produce mechanical
energy. Modern hydropower, sometimes referred to as “white coal,”
is harnessed in plants where electricity is generated. Around 40
countries use hydropower to produce more than a fifth of their
electricity. Hydropower accounts 16% of electricity worldwide, behind
coal and gas, but ahead of nuclear.
World Electricity Generation
Coal, Oil, Natural gas Nuclear power Hydroelectricity Wind power Solar power
Coal, Oil, Natural gas
69.94%
Nuclear power
11.01%
Hydroelectricity
16.32%
Wind power
2.32%
Solar power
0.41%
5. From Dams to Plants
• A hydroelectric power plant has three main components:
1.) DAM
• A hydroelectric dam is one of the major
components of a hydroelectric facility. A dam is
a large, man-made structure built to contain
some body of water. In addition to
construction for the purpose of producing
hydroelectric power, dams are created to
control river flow and regulate flooding.
• A dam creates a large waterfall and stores
enough water to supply the plant at all times.
As well producing and storing energy, a dam
also helps to regulate flooding.
2.) PENSTOCK
• A penstock is a group of pipes that transport
pressurized water from a reservoir (dam) to
the turbines installed in a hydro-electric power
plant. Depending on the site’s topography and
the technological options available at the time
of their construction, penstocks may be
located above or below ground and made out
of either steel, reinforced or prestressed
concrete, composite materials or even cast
iron.
• A penstock channels water from its natural
environment (river or lake) to supply the dam
reservoir. It may be an open channel, a tunnel
or pipeline.
3.) POWERHOUSE
• Power house is a building provided to
protect the hydraulic and electrical
equipment. Generally, the whole
equipment is supported by the foundation
or substructure laid for the power house.
• A powerhouse also houses the turbines
driven by the waterfall and the generator
driven by the turbines at a hydropower
facility.
6. Types of Hydropower Plant
• There are primarily three types of hydropower plants since the type
of plant changes depending on the site's layout, the waterway, and
the intended application or use.
1.) Run-of-river plants
• Also called a diversion, these type of hydropower plant produces energy using the flow of the river. With dams less
than 25 meters high, these “small hydro” plants generate power continuously to meet daily needs. It channels a
portion of a river through a canal and/or a penstock to utilize the natural decline of the river bed elevation to
produce energy. A penstock is a closed conduit that channels the flow of water to turbines with water flow
regulated by gates, valves, and turbines. A diversion may not require the use of a dam.
2.) Off-stream plants
• These are modular, meaning that energy can be produced on demand, with dams used to create reservoirs that can be released as
required. On lakes, water falls from a significant height (over 300 meters); on locks, from between 20 and 300 meters. It is often a
major hydroelectric plant, employs a dam to hold river water in a reservoir. Water released from the reservoir runs through a
turbine, turning it and activating a generator, which produces energy. The water may be released to satisfy changing electrical
requirements or other purposes like as flood control, recreation, fish passage, and other environmental and water quality
concerns.
3.) Pumped storage power plants
• Another kind of hydropower, known as pumped storage hydropower, or PSH, functions similarly to a gigantic battery. A PSH
plant may store electricity generated by various power sources, such as solar, wind, and nuclear, for later consumption. These
installations store energy by pumping water from a lower-elevation reservoir to a higher-elevation reservoir. When the
demand for power is low, a PSH plant stores energy by pumping water from a lower reservoir to a higher reservoir. During
moments of heavy electrical demand, the water is discharged back into the lower reservoir and powers a turbine, generating
energy.
7. Site Selection and Financing
• First, the right topographical, geological and
hydrographical conditions are required. The biggest
hydropower producers are countries crossed by
fast-flowing rivers and mountainous countries. Gorges in
rivers are good places for building dams. Similarly, a large
flat valley is ideal for holding water. There must be
sufficient rainfall in the catchment area (all upstream
water).
• Large and medium-size dams are very expensive to build.
Governments are increasingly trying to obtain funding
from private sources or large international organizations
such as the World Bank for these projects. But because the
payback period is seen as too long, hydropower projects
have difficulty attracting investors. The future of
hydropower therefore depends to a large extent on the
persuasiveness of states and potential public-private
partnerships.
The following factors must also
be considered while deciding
where to locate the
hydropower station.
1. The quantity of water
available
2. Storage of water
3. Head of water
4. The distance of power
station site from load
centers
5. Accessibility of the site
6. Water pollution
7. Geological investigation
8. Environmental effect
8. The Advantages of Hydropower
• The water used to create hydropower is renewable and storable, which
means it may be utilized during peak demand and then reused. Because a
hydro plant may achieve its full rated capacity in just a few minutes, this
method of storing potential energy is very efficient. In comparison, a
thermal energy plant takes around 10 hours to achieve full capacity, while
a nuclear reactor takes four times as long. Hydropower is incredibly
efficient, converting 90% of the energy in water into electricity.
Furthermore, hydropower facilities produce no greenhouse gases, other
pollution, or trash. While building requires a significant investment,
operation and maintenance costs are minimal. Plants have an
exceptionally long life span, and the technology is exceedingly dependable.
But despite its advantages, there are still some cons on hydropower.
9.
10. • Hydropower has long been a traditional source of clean
energy and deserves to be rediscovered and renewed. It can help
drain marshy land and irrigate fields and can be produced by either
large stations or small plants. It even has huge potential for domestic
use. Hydropower provides benefits beyond electricity
generation by providing flood control, irrigation support, and
clean drinking water. Hydropower is affordable. Hydropower
provides low-cost electricity and durability over time compared to
other sources of energy. Converting over 90% of available energy
into electricity, hydropower is the most efficient source of electrical
energy. By comparison, the best fossil fuel power plants operate at
approximately 60% efficiency. Hydropower facilities have a very long
service life, which can be extended indefinitely, and further improved.
