sources of electricity generation and supply

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METHODS OF GENERATINGELECTRICITY

Presented by:- Deepanshu SetiaEnroll. No. :- A512040110025th SemesterB.ARCH


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Electricity generation

Electricity generation is the process of generating electricalpower from sources ofprimary energy.

The fundamental principles of electricity generation werediscovered during the 1820s and early 1830s by the Britishscientist Michael Faraday

For electric utilities, it is the first process in the delivery of

electricity to consumers. The other processes,electricity transmission ,distribution, and electrical powerstorage and recovery using pumped-storage methods arenormally carried out by the electric power industry.


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Primary energy

Primary energy is an energy form found in nature that hasnot been subjected to any conversion or transformationprocess. It is energy contained in raw fuels, and other forms

of energy received as input to a system. Primary energy canbe non-renewable or renewable.

Non renewable sources:-Oil or crude oil

Coal or natural gasNatural uranium

Renewablesources:-Solar energy

Wind energyTidal energyBiomass energyGeothermal energy


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Natural uranium (NU) refers to uranium withthe same isotopic ratio as found in nature. Itcontains 0.7% uranium-235, 99.3% uranium-238, and a trace of uranium-234 by weight(0.0055%). In terms of the amountof radioactivity, approximately 2.2% comes fromuranium-235, 48.6% uranium-238, and 49.2%uranium-234.

What is natural uranium ?


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Conversion to secondary energy

Primary energy sources are transformed in energyconversion processes to more convenient forms of energy(that can directly be used by society), such as electricalenergy, refined fuels, or synthetic fuels such as hydrogen

fuel. In the field of energetics, these forms arecalled energy carriers and correspond to the concept of"secondary energy" in energy statistics.

Energy carriers are energy forms which have been

transformed from primary energy sources. Electricity is oneof the most common energy carriers, being transformedfrom various primary energy sources such as coal, oil,natural gas, and wind.


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Central power stations became economically practicalwith the development of alternating current powertransmission, using power transformers to transmitpower at high voltage and with low loss. Electricity hasbeen generated at central stations since 1881. The firstpower plants were run on water power or coal, and todaywe rely mainly on coal ,nuclear , naturalgas, hydroelectric, wind generators, and petroleum, witha small amount from solar energy, tidal power,

and geothermal sources.

The use of power-lines and power-poles have beensignificantly important in the distribution of electricity.

History


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Methods of generating

electricityThere are seven fundamental methods of directly transformingother forms of energy into electrical energy:Static electricity, from the physical separation and transport ofcharge (examples: lightning)

Electromagnetic induction, where an electricalgenerator, dynamo or alternator transforms kineticenergy (energy of motion) into electricity. This is the most usedform for generating electricity and is based on Faraday's law. It

can be experimented by simply rotating a magnet within closedloops of a conducting material (e.g. copper wire)

Electrochemistry, the direct transformation of chemicalenergy into electricity, as in a battery, fuel cell or nerve impulse


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Piezoelectric effect, from the mechanical strain of

electrically anisotropic molecules or crystals. Researchers atthe US Department of Energy's Lawrence Berkeley NationalLaboratory (Berkeley Lab) have developeda piezoelectric generator sufficient to operate a liquid crystaldisplay using thin films of M13 bacteriophage.

Nuclear transformation, the creation and acceleration ofcharged particles (examples: betavoltaics or alphaparticle emission)

Photoelectric effect, the transformation of light into electrical

energy, as in solar cells

Thermoelectric effect, the direct conversion of temperaturedifferences to electricity, as in thermocouples, thermopiles,and thermionic converters.


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All turbines are driven by a fluid acting as an intermediateenergy carrier. Many of the heat engines just mentionedare turbines. Other types of turbines can be driven by wind orfalling water.Sources include:

Steam - Water is boiled by:Nuclear fission

The burning of fossil fuels (coal, natural gas, orpetroleum). In hot gas (gas turbine), turbines are driven

directly by gases produced by the combustion of naturalgas or oil. Combined cycle gas turbine plants are drivenby both steam and natural gas. They generate power byburning natural gas in a gas turbine and use residual heatto generate additional electricity from steam. These plantsoffer efficiencies of up to 60%.

Turbines


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TURBINES


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By Renewable sources of energy the steam is generated by:BiomassSolar thermal energy (the sun as the heatsource): solar parabolic troughs and solar powertowers concentrate sunlight to heat a heat transfer fluid,

which is then used to produce steam.Geothermal power. Either steam under pressureemerges from the ground and drives a turbine or hotwater evaporates a low boiling liquid to create vapour todrive a turbine.Ocean thermal energy conversion (OTEC): uses the

small difference between cooler deep and warmer surfaceocean waters to run a heat engine (usually a turbine).


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Other renewable sources:

Large dams such as Hoover Dam can provide largeamounts of hydroelectric power; it has2.07 GW capability.

Water (hydroelectric) - Turbine blades are actedupon by flowing water, produced by hydroelectricdams or tidal forces.Wind - Most wind turbines generate electricity fromnaturally occurring wind. Solar updraft towers usewind that is artificially produced inside the chimney byheating it with sunlight, and are more properly seen asforms of solar thermal energy.


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Reciprocating engines

Small electricity generators are often poweredby reciprocating engines burning diesel, biogas or naturalgas. Diesel engines are often used for back up generation,

usually at low voltages. However most large power gridsalso use diesel generators, originally provided asemergency back up for a specific facility such as ahospital, to feed power into the grid during certaincircumstances. Biogas is often combusted where it isproduced, such as a landfill or wastewater treatment plant,

with a reciprocating engine or a microturbine, which is asmall gas turbine.


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GENERATORS


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Photovoltaic panels

Unlike the solar heat concentrators mentionedabove, photovoltaic panels convert sunlight directly toelectricity. Although sunlight is free and abundant, solarelectricity is still usually more expensive to produce than

large-scale mechanically generated power due to the cost ofthe panels. Low-efficiency silicon solar cells have beendecreasing in cost and multijunction cells with close to 30%conversion efficiency are now commercially available. Over40% efficiency has been demonstrated in experimentalsystems.


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PHOTOVOLTAIC PANELS


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Until recently, photovoltaics were most commonly used inremote sites where there is no access to a commercial

power grid, or as a supplemental electricity source forindividual homes and businesses. Recent advances inmanufacturing efficiency and photovoltaic technology,combined with subsidies driven by environmentalconcerns, have dramatically accelerated the deployment of

solar panels. Installed capacity is growing by 40% per yearled by increases in Germany, Japan, California and NewJersey.


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attains between 50 70% efficiency

one windmills average energy output ranges from 11.4 W/m^2 57 W/m^2 depending on how windy

wind farms tend to generate between 50 and 600 Kw

California currently produces of all the wind generatedelectricity in the world.

North Dakota with 20 times the wind potential of California hasnot erected a single wind turbine

Wind energy


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Kilronan Wind Farm In Ireland


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Problems with wind power

Wind variability must be overcome by system designDifferences in pressure gradients around wind turbinesaffect birds

Noise from the turbines affects people and animals


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Conversion from potential energy of water to electricenergy is at 80 90% efficiency.Hydroelectric projects in the United States have rated

capacities from 950 6480 MWThe use of Water Power is much greater in some othercountries.

Norway obtains 99% of its electricity from waterpower. Nepal, Brazil, and New Zealand are closeseconds.

Hydro electric power


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Shasta Dam In California


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Problems

About 50% of the United States potential forhydroelectric energy has been tapped. However, furtheradvances are unlikely.The Wild and Scenic River Act and the Endangered

Species Act have inhibited development of some sitesSilt collection in hydroelectric Dam storage volumes overtime causes maintenance issues, as well asenvironmental concernsThe loss of free flowing streams and land due to floodingbehind the dam disturbs the life of species: eg SalmonPossibility of dam failure


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Fossil Fuels Oil RefineryPasadena - Texas

Standard Large Power Plants Provide 1 Giga-watt of electric powerand releases 2 Giga-watts of thermal power as waste heat. An

efficiency averaging around 30%.

-9000 tons of coal a day-40,000 barrels a day or one tanker a week of oil-generates about 5.3 x 10^9 kwh/year-powers a city of a million people


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-In normal operations a nuclear reactor produces some

environmental emissions. E.g.: escape of radioactive fissionproducts through cracks and diffusion, radioactive H3 in smallamounts in discharged water

-Core meltdown are possible, but unlikely due to negativefeedback and shutdown systems

-Even after shutdown there is 7% of normal power generationstill in the reactor fuel rods. This may be sufficient enough tomelt core and destroy the reactor, if cooling water is notsupplied

-A study entitled Severe Accident Risks: An Assessment for FiveUS Nuclear Power Plants conducted by NRC in 1990, shows thatfor all the 109 reactors now operating in the United States over a30 year lifetime there is about a 1% chance of a large releasedue to internal events.

Problems


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-Solar Power uses the sun energy to either boil water ordirectly converts solar energy to electrical energy-Ocean Thermal Energy Conversion uses temperaturedifferences between different depths of ocean water to drive a

heat engine. Working fluid is ammonia which is gas at roomtemperature.-Biomass Energy: Municipal Solid Waste burning wastes todrive heat engines-Geothermal Energy based on naturally occurring heat in theEarth in the Earth due to radioactive decay-Tidal Energy uses the gravitational pull of the moon on ouroceans to drive turbines

Other forms of energy


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Proportion of Worlds energyconsumption - 1997

Proportion of the worldsElectricity generation - 1997


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sources of electricity generation and supply

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