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Power Stations

Ah, here we are, the perfect place to fly a kite, well away from any power lines. Can you see the power station? That is where electricity is made. The electricity then travels from the power station and joins the national grid through the high voltage power lines carried by those pylons you can see in the distance. Power stations use different fuels to generate electricity. The one over there is a gas fired power station. Others use coal or nuclear fuel. Some electricity is generated from renewable sources of energy such as sunlight, water flow (hydroelectric power stations and wave farms) or the wind. You can see some wind turbines on top of the far hill.

Ask Julie

What sort of fuels do power stations use?

Power stations usually burn fossil fuels to generate electricity, but renewable energy is going to become more important throughout the 21st century.

Fossil Fuels

Nearly all the energy we use comes from fossil fuels such as coal, oil and natural gas. They are called non-renewable energy sources because once they are used up they will take millions of years to reform.

Coal

Coal began life as plant life, trees and shrubs, 280 to 360 million years ago. Buried, heated and compressed by overlying rocks, the vegetation formed layers – seams – varying in thickness. Coal was the first fossil fuel to be exploited, before we discovered the potential uses of petroleum oil and gas.

Gas

Natural gas is found in similar places to oil. It is thought to have been formed millions of years ago by decaying vegetation. Unlike coal, which is used to produce steam to drive the turbines in a power station, gas is burned and the heat is used to drive a turbine directly.

Oil

Petroleum oil is a thick black fluid found in permeable rocks, which hold it as a sponge holds water. How it came to be there is uncertain. Some scientists believe it formed from compressed vegetation, like coal, while others disagree. Natural gas is found in the same kinds of location as oil.

Orimulsion

Recently a completely new fuel has been developed, which could become a useful alternative. Called Orimulsion, it is based on bitumen, a tarry substance used for heavy-duty waterproofing and surfacing. Bitumen is mixed with water to form an emulsion, which can be pumped through pipes and burns very like an oil flame. There are large reserves of bitumen in Venezuela where Orimulsion is processed.

Renewable Fuels

Burning fossil fuels like oil, coal and gas causes the release of large amounts of the ‘greenhouse gas’ carbon dioxide. Scientists predict if energy consumption continues to increase at the present rate the temperature of the earth will raise 2 degrees causing global warming.

The governments of the world agreed at the Kyoto summit in 1997 to reduce carbon dioxide (CO2) emissions by 2010. So the race is on to find other ways of producing electricity.

Many projects are underway to use Wind, Hydro Electricity, Solar Power, Biofuels and Geothermal Energy. These are called renewable energy sources.

Scientists are developing ways of using these economically, and to give sufficient energy to meet our needs.

Solar Power

The most economical effective means of harnessing solar heat in the UK is through passive solar design. This uses the form of fabric of a building to capture solar radiation and thereby reduce the need for artificial lighting, heating and cooling.

Did you know that more energy arrives from the sun in one hour than the whole planet uses in one year?

Biofuels

Biofuels are any solid liquid or gaseous fuels produced from organic matter, either directly from plants or indirectly from industrial, commercial, domestic or agricultural wastes. Biofuels can be burnt to produce heat or electricity.

Wind Power

Power can be extracted from the wind by use of a wind turbine. Air flowing over the turbine blades creates a turning force that can be used to generate electricity or drive pumps. Wind turbines are either set up individually or clustered to form wind farms. In the UK most wind farms consist of between 10 and 25 turbines and can generate enough electricity for 5,000 homes. This would save the emission of around 17,000 tonnes of carbon dioxide a year.

Water Power

Power can be extracted from water in three ways.

1. The tidal rise of a river or estuary may be captured by a barrage and the tidal water passed through turbines to generate electricity.
2. In Hydro Schemes, turbines are driven directly by water from reservoirs or the run of the river, it can only be used in hilly areas where there is a good supply of water.
3. The mechanical energy of waves at sea may be captured by wave-powered devices and converted into electricity.

Geothermal heat

The heat flowing outwards from the earth’s core can be utilised by tapping the heat from aquifers – underground deposits of hot water in porous rocks – or from hot dry rocks (HDR). HDR technology involves pumping water through fissures in naturally hot rocks to produce steam for generating electricity or for heating.

Next page: Generating electricity

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