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Power stations
Power stationsThermal power stationsSankey diagramsWorld power generationTsokos p.430 qns3-7
11May 2012
11 Physics 8.1, 8.2, 8.3 Power generation Tsokos 7.1
Three Gorges Dam, Hydroelectric Power Station, China (22GW- largest power plant in the world)
Wind turbine, Denmark (40kW)
Nellis Solar plant, USA (200kW)
Wave generator, Denmark140kW (with 33kW wind turbines)
Thermal Power StationA In the boiler, the fuel burns in
air, making heat.
G The heat boils the water and
turns it to steam.
E The steam travels along pipes
and steam pressure turns the
turbine.
I The turbine drives the
alternator.
H The alternator generates
electricity.
C A step up transformer
increases the voltage of the
electricity.
B The electricity travels to
homes and factories along
power cables.
D In the condenser, cooling
water cools the steam.
F The recycled water is fed
back to the boiler to be used
again.
Power station efficiencyGenerating electricity in a typical thermal power station has an efficiency around 35%.Cyclical processes cannot convert all thermal energy to work. Excess heat can be used in combined heat and power plants.
Degraded energy
energy lost due to cyclical process of converting heat into work (2nd law of thermodynamics)
Fossil fuel typical efficiency
maximum efficiency
coal 35% 42%
oil 38% 45%
natural gas 45% 52%
heat engine
Tsokos p.416
Construct a Sankey diagram for a bouncing ball of mass 1kg dropping from 1m which bounces to 70% of
its height each bounce.
Generator (alternator)
Coil rotates in a magnetic field, kinetic energy is converted to electrical energy
Coal-fired thermal power station, Sofia, Bulgaria (0.5GW)
Susquehanna , Nuclear Power plant, Pennsylvania, USA (1.2GW)
Nesjavellir, Geothermal Power Station, Iceland (0.6GW)
Power generation
- Coal Oil NaturalGas Nuclear Hydro other Total
Electricity (TWh /year)
8,263 1,111 4,301 2,731 3,288 568 20,261
Proportion 41% 5% 21% 13% 16% 3% 100%
Source of Electricity (World total year 2008)
Sources of electricity in France in 2006