This GCSE Geography quiz will test you on solar power. The increase in world population, increased wealth and technological advances have created an ever increasing demand for energy. In emerging economies, the cheapest and most effective way to obtain this energy is from the unsustainable burning of fossil fuels. In MEDCs, since the end of the twentieth century, there has been a drive towards increasing the amount of energy generated from cleaner and sustainable sources. One of these is to use the energy arriving at the surface of the Earth from the Sun. This form of renewable energy is not available to all countries, either because of their economic status or they don't have high enough levels of sunlight.
Solar power is also known as solar energy and uses the heat and the light from the Sun. As with most forms of renewable energy, the energy is spread out and so it takes large areas of solar collectors to obtain significant amounts.
This can have social and economic effects on local populations as farmland is taken over for energy production. On a smaller scale, it is possible to fit solar panels and solar cells to individual dwellings in order to reduce their dependence on energy from other sources.
The simplest way to use solar power is to heat water using solar panels. A domestic solar hot water system comprises a sealed box with a glass front to allow the heat from the Sun to enter. The box contains tubes that are painted black (black absorbs heat the best) through which water is circulated by a pump. The water is warmed by the Sun's heat and can be stored, ready for use, in an insulated tank. It is expensive to install but costs very little to run. It has disadvantages like it doesn't work at night and it is less effective in the winter.
The Sun's heat can also be used to generate electricity, there are several solar power stations around the world. These have different designs but all work by focussing the heat from the Sun using mirrors in order to turn water into steam. The steam can then be used to turn a turbine which turns a generator. These power stations produce less electricity than conventional methods and have similar advantages and disadvantages to using the Sun's heat for heating domestic hot water.
Light from the Sun can be used to generate electricity directly using panels of photovoltaic cells. These can be fitted to individual houses or fixed together in huge arrays. Photovoltaic cells are not very efficient at converting light to electricity, most commercial cells convert only about a quarter of the incoming energy to electricity. They also become covered with dust which means they must be regularly cleaned if they are to work at their maximum efficiency.