Physics GCSE: Energy Transfers
Alternative energy sources
Below is some general information about alternative energy sources, but there is a lot more on the web. Try the Centre for Alternative Technology or The Guardian Renewables page as a starting point if you are researching this area. For the exam, make sure that you know the advantages and disadvantages of each energy source.
Most of the alternative energy sources are renewable. This means there is either an endless supply of them so that they will not run out, or they can be easily replaced.
The power of water
Nothing new here! Water wheels were used at the start of the industrial revolution. Now we can use water running down a hill or falling over a dam to turn a turbine. This is called hydro-electric power (HEP).
Some developing countries get all their energy from hydro-electricity schemes on large dams. The Aswan dam was the first and most famous, in Egypt on the Nile. The down side is that the large lakes made behind a dam can drastically change the countryside, sometimes covering small villages.
Big waves at sea also have a lot of energy - too much energy really, as no large-scale scheme has been designed to cope with it! Also, the tide has a lot of energy. If you block in the water at high tide and then let it out through a turbine as the tide falls, you can generate electricity. But as with the dams, this alters the natural water levels, so the local habitat is affected.
Harnessing the weather
Solar power - The energy from the sun can be changed into electrical energy using solar panels. This is used in the UK even though it's not always sunny! Solar panels are often used alongside other energy sources, as it is not powerful enough to be used as the only source. Although the sun's energy is free the actual solar panels are very expensive to make which makes solar energy quite an expensive option.
This year, a company has started marketing roof tiles that are also solar cells, which can supplement your domestic electricity.
Wind power - Britain is a windy country! A lot of farmers make money by renting out land to build wind farms. This is a group of wind turbines that generate electricity from wind as slow as 5 miles per hour. It may only be a few years before over 10% of our electricity is wind generated. Look out too for the first wind turbines in back gardens. Unfortunately, some people don't like wind farms because they spoil the view or make a noise.
Other alternatives
Geothermal power uses the natural heat in volcanic rock under the ground to generate electricity. This is popular in Iceland but not likely to happen in the UK as the structure of the Earth under the surface is not as suitable.
Biomass - when dead plants and animals rot the bacteria involved produce methane gas. This gas can be collected and burnt as a fuel. It is often called biogas. Although this makes good use of natural waste, unfortunately burning methane produces pollution like the fossil fuels.
Burning waste - Burning rubbish is not a way to avoid pollution, but it does preserve fossil fuels as well as avoid rubbish having to be put in landfill sites.
Crops for fuel - This is particularly popular in third world countries, as it is cheaper than buying fossil fuels. In Brazil, they grow a lot of Sugar Beet. It is processed into alcohol and used instead of petrol in cars.
