power generation

1. POWER GENERATION

2. history
■ The fundamental principles of electricity generation were discovered during the
1820s and early 1830s by the British scientist Michael Faraday.
■ This method is still used today: electricity is generated by the movement of a
loop of wire, or disc of copper between the poles of a magnet.
■ Central power stations became economically practical with the development
of alternating current power transmission, using power transformers to transmit
power at high voltage and with low loss.
■ Electricity has been generated at central stations since 1882. The first power
plants were run on water power or coal, and today rely mainly
on coal, nuclear, natural gas, hydroelectric, wind generators, and petroleum,
with supplementary amounts from solar energy, tidal power, and geotherm mal
sources. The use of power-lines and power-poles have been significantly
important in the distribution of electricity.

3. introduction
■ Electricity generation is the process of generating electric power from
sources of primary energy.
■ For electric utilities, it is the first process in the delivery of electricity to
consumers.
■ The other processes as transmission, distribution, energy storage and recovery
using pumped-storage methods are normally carried out by the electric power
industry.
■ Electricity is most often generated at a power
station by electromechanical generators, primarily driven by heat
engines fuelled by combustion or nuclear fission but also by other means such
as the kinetic energy of flowing water and wind. Other energy sources include
solar photovoltaics and geothermal power.

4. Economics of power generation
■ The selection of electricity production modes and their economic viability
varies in accordance with demand and region.
■ The economics vary considerably around the world, resulting in widespread
selling prices, e.g. the price in Venezuela is 3 cents per kWh while in
Denmark it is 40 cents per kWh.
■ Hydroelectric plants, nuclear power plants, thermal power
plants and renewable sources have their own pros and cons, and selection is
based upon the local power requirement and the fluctuations in demand.
■ All power grids have varying loads on them but the daily minimum is the
base load, supplied by plants which run continuously. Nuclear, coal, oil and
gas plants can supply base load.

5. Environmental concerns
■ Variations between countries generating electrical power affect concerns
about the environment.
■ In France only 10% of electricity is generated from fossil fuels, the US is higher
at 70% and China is at 80%.
■ The cleanliness of electricity depends on its source. Most scientists agree that
emissions of pollutants and greenhouse gases from fossil fuel-based
electricity generation account for a significant portion of world greenhouse
gas emissions.
■ Electricity generation is the fourth highest combined source of NOx, carbon
monoxide, and particulate matter in the world. "levels of (carbon) emissions
from nuclear power were approximately three times lower per kilowatt hour than
those of solar, four times lower than clean coal and 36 times lower than
conventional coal".

6. CONVENTIONAL SOURCES OF POWER
GENERATION
1. Thermal Sources.
2. Hydel Sources.

7. 1.Thermal sources
1.1 steam power plant
■ Thermal energy is the energy released on combustion of fossil fuels (e.g.
coal, natural gas). This energy is used to turn water to steam and rotates
steam turbines which drives an electric generator.
■ Continuous source of fuel is a required for thermal power generation.
■ High pressure superheated steam is expanded in series of turbines namely
high pressure, intermediate pressure and low pressure turbines coupled to an
alternator. As a result alternator rotates and electrical energy is generated
which is stepped up with the help of a transformer for transmission.
■ This is the a source through which 60% of world’s total energy is produced.

8. Fig.2- schematic of thermal power plant.

9. 1.2 Gas power plant
■ Gas turbine engines derive their power from burning fuel in a
combustion chamber and using the fast flowing combustion gases to
drive a turbine in much the same way as the high pressure steam drives
a steam turbine.

10. 1.3 Nuclear Source
Nuclear Power Plant
■ Nuclear power plant uses the same technology as that of conventional
steam power generation with nuclear reactor for heat generation
instead of coal furnace and boiler.
■ Most nuclear power stations use Uranium as fuel.
■ The tremendous amount of heat energy produced in fission of Uranium
or other heavy elements in nuclear reactor is extracted by pumping
fluid.
■ The other process is same as conventional steam power plant.
■ Fourteen percent of the world's electricity is generated by nuclear
energy.

11. Fig.3- schematic of nuclear power plant

12. 2. Hydel Sources
hydro electric power plants
■ The power generated is directly proportional to the head available, as greater
head implies greater pressure to drive turbines, this is the basic principle of
hydroelectric power plant.
■ Artificial reservoir like dam is built where natural lake or reservoir is not
available. Dam ensures that water is available from wet season to the next dry
season.
■ Water from the storage reservoir is carried through penstocks or canals to the
powerhouse. Water after passing through the turbine is discharged to the
stream.

13. Fig-3. schematic of hydro power station

14. WATER SOURCES (LARGE) LOCATION CAPACITY
TARBELA
Tarbela, Khyber Pakhtunkhwa
(KPK)
3478 MW
Ghazi-Barotha Attock, Punjab 1450
Mangla Dam Mirpur, AJK 1120
POWER GENERATION IN PAKISTAN
 Total need or avg demand=17000mw
 Average short fall=2000mw to 5000mw
 Total thermal plants (steam, gas, combined, large, small)=37
 Total hydro power stations= 91(4-large , rest of all are small)
Total Production Is 29.9% OfAllThe Sources.
THERMAL POWER PLANTS LOCATION CAPACITY
KOT ADDU POWER STATION KOT ADDU, PUNJAB 1350 MW
Pak Gen (Pvt) Limited Thermal
Power Station
Muzaffargarh, Punjab
1350
GUDDU POWER STATION GUDDU,SINDH 2402
Total Production: Gas (29 %)+Oil(35.2 %)+(Nuclear 4%)=64.2% Of AllThe Sources.

15. Under construction power resources
projects location Date of completion capacity
Neelum–Jhelum
Hydropower Plant
Muzaffarabad, Azad
Kashmir, Neelum River
2018
969 MW
Tarbela DamExtension-
IV
Tarbela, Sawabi
District, Kpk
2018
1410 MW
Dasu Dam- Stage I
Kohistan.District, KPK,
Dasu, Indus River
2022
2160 WM
Kohala Hydropower
Project
Muzaffaraba
District,Azad
Kashmir, Jhehlum River
2022 1124 WM
Port Qasim Coal Power
Project
Karachi, Sindh 2018 1320 WM
Sindh Engro Coal Power
Project
Tharparkar, Sindh 2018 1320 MW
Hub Coal Power Project Hub, Balochistan 2018 1320 WM
4 major from hydel sector, 12 from thermal sector (large power production units)

16. NON CONVENTIONAL SOURCES OF POWER
PRODUCTION
 Solar energy
 tidal energy
 geo-thermal energy
 wind energy
 biomass energy, etc.

17. 2.1 Solar energy
■ More energy form sun strikes the earth in one hour than all the energy consumed
on the planet in a year.
■ Solar energy, received in form of radiation, can be converted directly or indirectly
into other forms of energy such as heat and electricity.
■ Solar energy can be converted into electricity in two ways: (1) Concentrated
SolarThermal Energy (CSTE) systems and (2) Photovoltaic systems.
■ CSTE systems consist of reflecting surfaces which concentrate solar radiations
onto boilers to produce high pressure steam required for power generation.
■ Photovoltaics or solar cells are devices which convert incident solar radiation to
electrical energy.

18. Fig 2.2 SolarThermal Electrical Power Plant
Fig-2.1 Photoelectric Effect

19. 2.2 Wind Power
■ Wind energy is harnessed via windmills which convert kinetic energy of
wind to mechanical energy.
■ A generator further converts it to electrical energy or is used to run the
machine such as for water pumping, mill grain etc.
■ Wind energy conversion systems uses two types of turbines classified as
Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines
(VAWT) on the basis of axis of orientation relative to wind stream.
■ A mechanical interface, consisting of a step-up gear and a suitable
coupling transmits the energy to an electrical generator.

20. Fig 2.3-WindTurbineTypes,VAWT- (a),(b),(c)
and (e) HAWT- (d)
Fig 2.4-WindTurbine showing gearbox

21. 2.3 Geothermal Energy
■ Geothermal energy is an inexhaustible source of energy present as heat
in the earth’s crust.
■ Geothermal energy of the Earth’s crust originates from the original
formation of the planet (20%) and from radioactive decay of minerals
(80%).
■ The geothermal gradient, the difference in temperature between the
core of the planet and surface, drives a continuous conduction of
thermal energy in form of heat from the core to the surface.

22. Fig 2.5-Heat Extraction from Hot Dry
Rocks
Fig 2.6-Schematic of Liquid Dominated Power Plant

23. 2.4 Biomass energy
■ Biomass is an organic matter produced by plants, both terrestrial and
aquatic, and their derivatives. It includes forest crops and residues, crops
grown for their energy content on ‘energy farms’ and animal manure.
■ One of the advantages of biomass fuel is that it is often a by-product,
residue or waste-product of other processes such as farming, animal
husbandry and forestry.
■ Biomass resources can be found in any of the three forms :
(1) Solid mass in form of wood and agriculture residue.
(2) Liquid fuels by converting biomass to methanol and ethanol.
(3) Biogas obtained on Bio digestion.

24. Fig 2.7-schematic of bio gas generation.

25. 2.5 Tidal Energy
■ Tides are generated by action of gravitational forces of the sun and moon
on the water of the earth.
■ The tides are periodic vertical rise and fall of water. The tidal rise and fall of
water is accompanied by periodic horizontal to and fro motion of water
called tidal currents.
■ The amplitude of tides covers a wide range from 25 cm to 10 m because of
the changing positions of the moon and sun relative to earth. The speed of
tidal currents is in the range of 1.8 km/h to 18 km/h.
■ The principle is to utilise differential head during high and low tides in
operating a hydraulic turbine. The idea is to hold water in a basin during
high tide and then let water back to sea through a turbine, thus producing
power.

26. Fig 2.7- schematic of tidal energy extraction.