Some examples of renewable energy sources:

Solar panels - which can either be used to directly heat water or to generate electricity. The generation of electricity via solar cells means that in hot countries air conditioning can be run by this means. You may not feel like a hot bath but life in a hot country without air conditioning can be awful!

Solar furnace - the Sun's rays focused by mirrors to generate very high temperatures.

Biomass - the Sun's energy is converted into chemical energy by growing plants. These can then be used for fuels in different ways.

A load of ......! Biogas - animal waste produces methane gas which is natural gas and can be used as fuel.

Wind - windmills can be used to generate electricity and wind farms are appearing in parts of the country which are prone to high winds. There is an associated noise problem and a wind farm can be visually intrusive.

Tidal - there are approximately two tides every twenty four hours and this energy can be harnessed by building a barrier across an estuary. A tidal power station has been operating at La Rance in Brittany since 1966. The Bristol Channel is a candidate for such a project and it has been calculated that the tidal power there could generate nearly one tenth of Britain's entire electricity supply. It would, however, be expensive to build and would have a major effect on wildlife in the area.

Hydroelectric - falling water can be used to turn turbines which generate electricity. This is widely used in mountainous countries, such as Norway.

Renewable sources of energy are vitally important to us, as is understanding the importance of not wasting energy. It is not ecologically sound to leave lights on, over-heat rooms etc. Low energy light bulbs save money in the long run and are eco-friendly! It is wise to insulate a house so that heat energy is not \wasted or dissipated through the roof or windows. It has to be said that it takes a long time to recuperate the actual cost of double glazing but it does cut down on the dissipation of energy.

Nuclear energy - this is a special case in terms of generation of electricity. It was originally heralded as the solution to the world's energy crisis. Since Chernobyl and Five Mile Island, we are more cautious. A process called nuclear fission can be harnessed to release a vast amount of energy. If this reaction is uncontrolled, a nuclear bomb results. However, when controlled, the reaction can be productive and used to generate electricity. Unfortunately, it has many associated problems, such as the radioactive waste produced. The JET project at Culham is investigating the possibility of harnessing nuclear fusion which is the same process that generates energy in the Sun. This has fewer associated problems with radioactive by-products but it is much more difficult to initiate the reaction.

Contents

Energy chains
The Law of Conservation of Energy, Fuels, Fossil fuels
Generation of Electricity
Energy and force
Energy reference material, Self assessment questions