Generating Electricity - Everyday Sorts of Power Stations
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by: SarahGreen | Total views: 22 | Word Count: 502
The electricity generation process involves a considerable number of energy changes, without regard for the primary power source that is used. Historically, electricity has been generated using fossil fuels, particularly coal. More lately, power stations have begun to use oil and gas as their energy source. Oil-fired power stations are not unusual in oil making countries, eg Indonesia. Gas burns more cleanly and efficiently than coal. It releases half as much carbon dioxide and more than 1000 times less sulphur dioxide per unit of energy.
Burning fossil fuels in power stations
The heat released from burning fossil fuels is used to boil water to produce steam. The steam is heated to really high temperatures in order that it is at high pressure and can turn gigantic steam turbines. Some of the energy of the steam is changed into movement, or kinetic energy, as the turbines spin. The turbines are hooked up to the coils of giant generators. The coils carry a current and act as electromagnets. As the turbines spin, they produce an electric current in the fixed coils surrounding them. This is fed into a power supply grid and carried to wherever in the network it is needed.
Power stations can't store surplus electricity, so electricity generation has to match demand. The power firms have to judge how much power will be required. During periods of hot weather, electricity demand may increase as more folks use air conditioning to keep their houses and offices cool. If power corporations' estimates are wrong, people may experience power cuts.
Power stations are not extremely efficient, and between 50 and 70 percent of the energy contained in the carbon-based fuel is wasted. Some of the heat energy will heat the encompassing air and escape through the boiler chimneys. The heat energy locked up in the steam can't all be transferred to the spinning turbines. Although the steam is cooler when it leaves compared with when it enters the turbines, it still is warm. The steam is carried to the cooling towers, where it cools adequately to compress back to water. The lukewarm water is then emptied Into a close-by brook or sea, where it may cause thermal (heat) pollution. Luke-warm water holds less oxygen than cold water. The addition of a huge quantity of lukewarm water may cause animals, for example fish, to 'suffocate', as they aren't able to extract enough oxygen from the water.
Combined heat and energy generating plants
Some power stations, called mixed heat and energy generating plants (CHP), attempt to utilize the waste heat. They pipe the waste hot water to surrounding companies and houses to provide heating. There are many such units in Germany, and many small towns are reaping benefits from this cheap energy source. Nonetheless this is only really possible with small and medium-sized power stations that are built close to cities. In numerous countries, especially the United Kingdom, power stations are found in more remote locations and so this power source wouldn't be as practical as even solar power.
About the Author
Sarah Green is an environmental campaigner, activist, and strong believer in home made energy. In her spare time, she reports on DIY alternative power plans and kits.
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