<P> Thermal energy is economical in areas of high industrial density, as the high demand cannot be met by renewable sources . The effect of localized pollution is also minimized as industries are usually located away from residential areas . These plants can also withstand variation in load and consumption by adding more units or temporarily decreasing the production of some units . Nuclear power plants can produce a huge amount of power from a single unit . However, recent disasters in Japan have raised concerns over the safety of nuclear power, and the capital cost of nuclear plants is very high . Hydroelectric power plants are located in areas where the potential energy from falling water can be harnessed for moving turbines and the generation of power . It is not an economically viable source of production where the load varies too much during the annual production cycle and the ability to store the flow of water is limited . </P> <P> Due to advancements in technology, and with mass production, renewable sources other than hydroelectricity (solar power, wind energy, tidal power, etc .) experienced decreases in cost of production, and the energy is now in many cases cost - comparative with fossil fuels . Many governments around the world provide subsidies to offset the higher cost of any new power production, and to make the installation of renewable energy systems economically feasible . However, their use is frequently limited by their intermittent nature . If natural gas prices are below $3 per million British thermal units, generating electricity from natural gas is cheaper than generating power by burning coal . </P> <P> Almost all commercial electrical power on Earth is generated with a turbine, driven by wind, water, steam or burning gas . The turbine drives a generator, thus transforming its mechanical energy into electrical energy by electromagnetic induction . There are many different methods of developing mechanical energy, including heat engines, hydro, wind and tidal power . Most electric generation is driven by heat engines . The combustion of fossil fuels supplies most of the energy to these engines, with a significant fraction from nuclear fission and some from renewable sources . The modern steam turbine (invented by Sir Charles Parsons in 1884) currently generates about 80% of the electric power in the world using a variety of heat sources . Turbine types include: </P> <Ul> <Li> Steam Large dams such as Three Gorges Dam in China can provide large amounts of hydroelectric power; it has a 22.5 GW capability . <Ul> <Li> Water is boiled by coal burned in a thermal power plant, about 41% of all electricity is generated this way . </Li> <Li> Nuclear fission heat created in a nuclear reactor creates steam . Less than 15% of electricity is generated this way . </Li> <Li> Renewables . The steam is generated by Biomass, Solar thermal energy where solar parabolic troughs and solar power towers concentrate sunlight to heat a heat transfer fluid, which is then used to produce steam, or Geothermal power . </Li> </Ul> </Li> <Li> Natural gas: turbines are driven directly by gases produced by combustion . Combined cycle are driven by both steam and natural gas . They generate power by burning natural gas in a gas turbine and use residual heat to generate steam . At least 20% of the worlds electricity is generated by natural gas . </Li> <Li> Water Energy is captured from the movement of water . From falling water, the rise and fall of tides or ocean thermal currents . Each driving a water turbine to produce approximately 16% of the world's electricity . </Li> <Li> The windmill was a very early wind turbine . In a solar updraft tower wind is artificially produced . Before 2010 less than 2% of the worlds electricity was produced from wind . </Li> </Ul>

Where do we get most of our electricity energy from