Download Hydroelectric power plants

“Hydroelectric power”
By
•DESHMUKH OM
•CHILLE SWAPNIL
•PATIL VIJAY
•TARAL TUSHAR
Under the guidance of
Prof. P. V. Kulkarni

How a Hydroelectric Power System
Works
it is important to note that when determining head, hydrologists
take into account the pressure behind the water.
water behind the dam puts pressure on the falling water.
Flowing water is directed at a turbine (remember turbines
are just advanced waterwheels).
 The flowing water causes the turbine to rotate, converting
the water’s kinetic energy into mechanical energy
It is the most widely used form of renewable energy,
accounting for 16 percent of global electricity consumption.
THE MECHANICAL ENERGY PRODUCE BY TURBINE IS CONVERTED
INTO ELECTRICAL ENERGY.
Flow Rate = the quantity of water flowing
When more water flows through a turbine, more electricity
can be produced.
The flow rate depends on the size of the river and the amount of
water flowing in it.
 Power production is considered to be directly proportional to
river flow.
 That is, twice as much water flowing will produce twice as much
electricity.
Head = the height from which water falls
The further the water falls, the more power it has.
The higher the dam, the farther the water falls, producing
more hydroelectric power.
Power production is also directly proportional to head. That is,
water falling twice as far will produce twice as much electricity.
1) Conventional (dams)Most hydroelectric power comes from the potential energy of dammed
water driving a water turbine and generator. The power extracted from the
water depends on the volume and on the difference in height between the
source and the water's outflow. This height difference is called the head.
2) Pumped-storageThis method produces electricity to supply high peak demands by
moving water between reservoirs at different elevations. At times of low
electrical demand, excess generation capacity is used to pump water into
the higher reservoir.
3) Run-of-the-riverRun-of-the-river hydroelectric stations are those with small or no
reservoir capacity, so that the water coming from upstream must be used
for generation at that moment, or must be allowed to bypass the dam.
 Hydroelectric power plants do not use up limited nonrenewable
resources to make electricity.
They do not cause pollution of air, land, or water
They have low failure rates, low operating costs, and are reliable.
The longer we delay the balanced development of our potential for
hydropower, the more we unnecessarily use up other vital resources.
n provide startup power in the event of a system wide power failure.
1) FlexibilityHydro is a flexible source of electricity since plants can be ramped
up and down very quickly to adapt to changing energy demands.
2) Low power costsThe major advantage of hydroelectricity is elimination of the cost of
fuel.
3) Reduced CO2 emissionsSince hydroelectric dams do not burn fossil fuels, they do not directly
produce carbon dioxide. While some carbon dioxide is produced during
manufacture and construction of the project, this is a tiny fraction
1) Ecosystem damage and loss of land
Large reservoirs required for the operation of hydroelectric power
stations result in submersion of extensive areas upstream of the dams,
destroying biologically rich and productive lowland and riverside valley
forests, marshland and grasslands.
2) Siltation and flow shortage
When water flows it has the ability to transport particles heavier than
itself downstream. This has a negative effect on dams and subsequently
their power stations,particularly those on rivers or within catchment
areas with high siltation.
3) Relocation
Another disadvantage of hydroelectric dams is the need to
relocate the people living where the reservoirs are planned.
1) LARGE HYDROPOWER
A large hydropower
facility has the capacity
to produce more than
30,000 kilowatts (kW) of
electricity.
The majority of
hydropower systems in
the U.S. fit in this
category.
Large hydropower
systems typically require
a dam.
2) SMALL HYDROPOWER
Small hydropower facilities
can produce
100 – 30,000 kilowatts (kW)
of electricity.
Small hydropower facilities
may involve a small dam, or
be a diversion of the main
stream, or be a run-of-theriver system.
3) Micro Hydropower
Micro hydropower
plants have the
capacity to produce
100 kilowatts (kW)
or less.
Micro-hydro
facilities typically use
a run-of-the-river
system.
A simple formula for approximating electric power production
at a hydroelectric plant is:
P=ρhrgk,
Where
P is Power in watts,
ρ is the density of water (~1000 kg/m3),
H is height in meters,
r is flow rate in cubic meters per second,
g is acceleration due to gravity of 9.8 m/s2,
K is a coefficient of efficiency ranging from 0 to 1.
Efficiency is often higher (that is, closer to 1) with
larger and more modern turbines.
 Annual electric energy production depends on the
available water supply.
Ten of the largest hydroelectric producers as at 2009.
Country
Annual
hydroelectric
production (TWh)
Installed
capacity (GW)
Capacity
factor
%
capacity
China
652.05
196.79
0.37
22.25
Canada
369.5
88.974
0.59
61.12
Brazil
363.8
69.080
0.56
85.56
United States
250.6
79.511
0.42
5.74
Russia
167.0
45.000
0.42
17.64
Norway
140.5
27.528
0.49
98.25
India
115.6
33.600
0.43
15.80
Venezuela
85.96
14.622
0.67
69.20
Japan
69.2
27.229
0.37
7.21
Sweden
65.5
16.209
0.46
of
44.34
total
CONCLUSION
Hydropower is important from an operational standpoint as it needs
no "ramp-up" time, as many combustion technologies do. Hydropower
can increase or decrease the amount of power it is supplying to the
system almost instantly to meet shifting demand. With this important
load-following capability, peaking capacity and voltage stability
attributes, hydropower plays a significant part in ensuring reliable
electricity service and in meeting customer needs in a market driven
industry. In addition, hydroelectric pumped storage facilities are the only
significant way currently available to store electricity.
REFERENCES
•http://ga.water.usgs.gov/edu/hyhowworks.html
•http://en.wikipedia.org/wiki/Hydroelectricity
•Reclamation Managing Water in the West, Hydroelectric Power, U.
S. Department of the interior Bureau of Reclamation Power Resource
Office, July 2005.
•www.howtopowertheworld.com/advantages-of-hydroelectric-energy
•www.conserve-energy-future.com/Disadvantages_HydroPower.php