hydropower final

8/7/2019 hydropower final

1/30

1

HYDROPOWER

Presented By:

GURPREET SINGH(500902014)

GURVINDER SINGH

(500902015)


2/30

FACTS ABOUT HYDROPOWER PLANT

The Worlds hydropower plants output a combined total of

675,000 megawatts, the energy equivalent of 3.6 billion barrels

of oil.

worldwide, hydro powers plant produce about 24% of worlds

electricity and supply more than one billion people with

power.

hydropower provides about 10% of electricity in united states.

India produces more than 12% of its electricity with

hydropower. Norway produces more than 99% of its electricity with

hydropower. New Zealand uses hydropower for 75% of its

electricity.

2


3/30

3

World Energy Sources


4/30

4

World hydro production


5/30

5

Major Hydropower Producers


6/30

HYDROPOWER PLANT

A hydropower plant uses the force of falling water to make

electricity.

Flowing water creates energy that can be captured and turned

into electricity. This is called hydroelectric power or

hydropower.

A typical hydro plant is a system with three parts:

a power plant where the electricity is produced.

a dam that can be opened or closed to control water flow.

a reservoir (artificial lake) where water can be stored.

6


7/30

7

Hydropower to Electric Power

PotentialEnergy

Kinetic

Energy

Electrical

Energy

MechanicalEnergy

Electricity


8/30

THE POWER OF WATER

Hydropower (from hydro meaning water) is energy that

comes from the force of moving water. The fall and movement

of water is part of a continuous natural cycle called the water

cycle.

The moisture eventually falls to the earth as rain or snow,

replenishing the water in the oceans and rivers. Gravity drives

the water, moving it from high ground to low ground. The

force of moving water can be extremely powerful.

Hydropower is called a renewable energy source because thewater on the earth is continuously replenished by precipitation.

As long as the water cycle continues, we wont run out of this

energy source.

8


9/30

9

Hydrologic Cycle

http://www1.eere.energy.gov/windandhydro/hydro_how.html


10/30

CONCEPT OF HYDRO POWER PLANT

Hydro system makes use of falling water in a stream or river

or storage dam between two points to generate mechanical

power through a turbine which is converted into electrical

power through a generator attached to turbine in a power

house. Power is expressed as kw or mw depending on capacityof station.

Amount of water flow diverted from stream or river or dam

called discharge (q) expressed in litres /sec or cumecs or

cusecs and difference in elevation between two upstream anddownstream points called gross head (h) expressed in feet or

metres.

Electricity generated in alternating current (ac) mode and

generating voltage expressed as volts (v) or kilo volts (kv)

depending on capacity of station.10


11/30

CONCEPT OF HYDRO POWER PLANT

continued..

After flow and gross head between two points measured -

hydraulic power calculated as below.

Power = qxhx9.81 watts; q in liters per second and h gross

head in meters.

Net head after allowing for frictional losses in water conductor

system and penstocks calculated using formulae.

In case of micro hydel projects, friction loss taken as 25% of

gross head. NET HEAD (h) = GROSS HEAD FRICTION LOSSES.

Used to calculate net hydraulic power. Mechanical power calculated using turbine efficiency. For

small shp - 65%.

Useful electrical power calculated using generator efficiency -

generally 80% for small size generators (induction generatorssuitable for direct drive .

11


12/30

COMPONENT OF HYDRO POWER PLANT

In general, larger the scale of a system, more the number of

components.

Intake: water from the river/spring/dam/irrigation channel is

diverted from its main course. Generally weir used to divert

water through intake into open channel.

Water conductor system : leads water from intake to head of

penstock.

De-silting basin with spillway : small tank designed to desilt

water. Provide spillway - a flow regulator for the channel.Combined with control gates to provide means of emptying

channel. Spill flow fed back to river.

Forebay tank: at head of penstock. Serves as buffer to control

sudden flow and pressure variations. 12


13/30

COMPONENT OF HYDRO POWER PLANT

continued..

Penstock: pipeline supplying water from forebay to turbine.

Mild steel, upvc and hdpe - most commonly used materials.

Power house: houses turbine generator with mechanical

control valves and electrical control panels. Switch yard and

connection to distribution system.

Tail race channel: leads water from turbines(s) back into

stream/river/irrigation channel.

Turbine and generator: hydro power in jet at end of penstock

transmitted to turbine runner - changes to mechanical power. Governor: ensures that generator is not affected when load on

it changes. Hydraulic, or electronic. Depends on the generator.

Generator: electricity generated when turbine drives generator

-most common type of generator produces alternative currentand known as alternator.

13


14/30

HYDROPOWER PLANT

Tail water

Draft tube gate

Draft tube

Turbine

Main valve

Penstock

Air inlet

Inlet gate

Surge shaft

TunnelSand trap

Trash rack

Self closing valve


15/30

HOW A HYDROPLANT WORKS

To generate electricity, a dam opens its gates to allow water

from the reservoir above to flow down through large tubes

called penstocks.

At the bottom of the penstocks, the fast-moving water spins

the blades of turbines.

The turbines are connected to generators to produce

electricity.

The electricity is then transported via huge transmission lines

to a local utility company.

15


16/30

STORING ENERGY

One of the biggest advantages of a hydropower plant is its

ability to store energy. The water in a reservoir is, after all,

stored energy. Water can be stored in a reservoir and released

when needed for electricity production.

During the day when people use more electricity, water can

flow through a plant to generate electricity. Then, during the

night when people use less electricity, water can be held back

in the reservoir.

Storage also makes it possible to save water from winter rains

for summer generating power, or to save water from wet years

for generating electricity during dry years.

16


17/30

hydrodams

A dam serves two purposes at a hydro plant. First, a dam

increases the head or height of the water. Second, it controls

the flow of water. Dams release water when it is needed for

electricity production. Special gates called spillway gates

release excess water from the reservoir during heavy rainfalls.

Dams are built on rivers where the terrain will produce an

artificial lake or reservoir above the dam. Most dams are built

for flood control and irrigation, not electric power generation.

Its easier to build a hydro plant where there is a natural

waterfall. Dams, which are artificial waterfalls, are the next

best way.

17


18/30

18

Conventional Impoundment Dam


19/30

19

Schematic of Impound Hydropower


20/30

20

Terminology

Head

Water must fall from a higher elevation to a lower oneto release its stored energy.

The difference between these elevations (the water

levels in the forebay and the tailbay) is called head

Dams: three categories

high-head (800 or more feet)

medium-head (100 to 800 feet)

low-head (less than 100 feet) Power is proportional to the product of

head x flow


21/30

21

Scale of Hydropower Projects

Large-hydro More than 100 MW feeding into a large electricity grid

Medium-hydro 15 - 100 MW usually feeding a grid

Small-hydro 1 - 15 MW - usually feeding into a grid

Mini-hydro Above 100 kW, but below 1 MW

Either stand alone schemes or more often feeding into the grid

Micro-hydro From 5kW up to 100 kW

Usually provided power for a small community or rural industryin remote areas away from the grid.

Pico-hydro From a few hundred watts up to 5kW

Remote areas away from the grid.


22/30

22

Ecological Impacts

Loss of forests, wildlife habitat, species.

Degradation of upstream catchment areas due to inundation of

reservoir area.

Rotting vegetation also emits greenhouse gases. Loss of aquatic biodiversity, fisheries, other downstream

services.

Cumulative impacts on water quality, natural flooding.

Disrupt transfer of energy, sediment, nutrients. Sedimentation reduces reservoir life, erodes turbines

Creation of new wetland habitat

Fishing and recreational opportunities provided by new

reservoirs


23/30

23

Environmental and Social Issues

Land use inundation and displacement of people

Impacts on natural hydrology

Increase evaporative losses

Altering river flows and natural flooding cycles

Sedimentation/silting

Impacts on biodiversity

Aquatic ecology, fish, plants, mammals

Water chemistry changes

Mercury, nitrates, oxygen Bacterial and viral infection

Seismic Risks

Structural dam failure risks


24/30

24

Impacts of Hydroelectric Dams


25/30

25

ADVANTAGES

Hydropowers fuel supply (flowing water) is clean and is

renewed yearly by snow and rainfall.

hydro plants do not emit pollutants into the air because they

burn no fuel. With growing concern over greenhouse gas emissions and

increased demand for electricity, hydropower may become

more important in the future.

Hydropower facilities offer a range of additional benefits.

Many dams are used to control flooding and regulate water

supply, and reservoirs provide lakes for recreational purposes,

such as boating and fishing.

Low operating and maintenance cost.


26/30

26

DISADVANTAGES

Damming rivers may permanently alter river systems and

wildlife habitats. Fish, for one, may no longer be able to swim

upstream.

Hydro plant operations may also affect water quality bychurning up dissolved metals that may have been deposited by

industry long ago.

Hydropower operations may increase silting, change water

temperatures, and lower the levels of dissolved oxygen.

Degradation of upstream catchment areas due to inundation of

reservoir area.

High initial capital cost.


27/30

27

Efficiency of Hydropower Plants

Hydropower is very efficient

Efficiency = (electrical power delivered (potential energy

of head water)

Typical losses are due to

Frictional drag and turbulence of flow

Friction and magnetic losses in turbine & generator

Overall efficiency ranges from 75-95%.


28/30

28

Hydropower Calculations

P = power in kilowatts (kW)

g= gravitational acceleration (9.81 m/s2)

L = turbo-generator efficiency (0


29/30

29

Calculation of head loss

g2

ch

2

!

Where:

hf = Head loss [m]

f = Friction factor [ - ]

L = Length of pipe [m]

D = Diameter of the pipe [m]

c = Water velocity[m/s]

g = Gravity [m/s2]


30/30

30

Documents

hydropower final