To meet the worldwide demand for more and more energy, scientists need to explore ways of increasing production from both existing and new sources of energy.
There are several factors to take into account: cost,
efficiency, convenience and environmental effect. What
suits one country, may not suit another.
How do we get our energy in the UK?
The UK uses 10 million million million joules
of energy each year. That's about 5000 joules
per person per second.
The average use of energy
in the UK is equivalent to each person in the
UK walking around with a 5 kilowatt heater
(switched on of course!).
These pie charts show the sources of energy used in the UK in 1990 and 2003. Notice the changes between the two pie charts and also how little of the UK's electricity has been generated using renewable sources of energy. The government aims to increase this to 10% by 2010.
Fuel types for energy generation in the UK for 1990 and 2003
How does the rest of the world get its energy? Here are some examples.
Hydroelectric Power
The largest amount of electricity generated from renewable energy sources currently comes from hydroelectric power stations.
How do they work? A large volume of water is stored in a reservoir behind a dam. When electricity is needed, water is allowed to rush down through pipes into the fans of turbine generators in the power station. The flow of the water turns the fans in the same way that wind turns the fans of a windmill.
Canada, for example, is very mountainous and its geography is ideal for building water-storage reservoirs. As a result, 60% of Canada's electricity is generated by hydroelectric power stations. However, in the UK only a very small amount, about 1%, of the electricity used is provided in this way.
Unfortunately, mountainous areas are also often very beautiful places and many people think that hydroelectric power stations spoil the landscape. What do you think?
We should remember also that things are not always as clear-cut as they seem. While hydroelectric power is generally seen as an environmentally friendly and renewable energy source, recent calculations have shown that hydroelectric energy generation using man-made reservoirs can in fact produce more greenhouse gases than the equivalent energy generated using fossil fuels. The reasons have to do with the amount of gases released by rotting vegetation in the water.
![[What is a watt? - 1 joule per second.]](../../images/what_watt.gif)
Hydroelectric Power