In GCSE Science students will spend some time looking at electrical energy. This is the fourth of six quizzes on that topic and it looks at how electricity can be generated from renewable resources, such as the Sun, the wind or water.
In conventional power stations, an energy source is used to heat water to make steam. The steam produced drives a turbine that is coupled to an electrical generator. Most of the energy sources create pollution and are non-renewable, and these are two big disadvantages.
Scientists and engineers have developed other ways of generating electricity from renewable and non-polluting energy sources. Water and wind can be used to drive turbines connected to generators and electricity can also be produced directly from the Sun's radiation. In some areas of the world, for example Iceland, volcanic activity creates hot water and steam. The steam can be piped to the surface of the earth where it can be used to drive turbines connected to generators.
These alternatives may sound like the perfect solution to the disadvantages of conventional power stations, but they too have their own problems. They produce a lot less electricity and they don't produce electricity all of the time, so using them as part of the National Grid is not always economic. Despite this, they do have their uses, for example, solar cells producing electricity from the Sun's rays can be used to power road signs and parking meters and hydroelectricity can be used in remote areas. Hydroelectric dams, wind farms and the like are often expensive to build but, apart from regular maintenance, the electricity then costs nothing to produce.
Some people object to these alternative forms of energy because they believe that they cause visual and noise pollution and destroy wildlife habitats. This is because they are often built in areas of natural beauty like the Lake District and the Welsh mountains.