Renewable energy sources

Renewable energy sources quickly replenish themselves and can be used again and again. For this reason they are sometimes called infinite energy resources.

Type of energyWhere it is fromAdvantagesDisadvantages
Solar Energy from sunlight is captured in solar panels and converted into electricity. Potentially infinite energy supply. Single dwellings can have own electricity supply. Manufacture and implementation of solar panels can be costly.
Wind Wind turbines (modern windmills) turn wind energy into electricity. Can be found singularly, but usually many together in wind farms. Wind is a potentially infinite energy supply. Manufacture and implementation of wind farms can be costly. Some local people object to on-shore wind farms, arguing that it spoils the countryside.
Tidal The movement of tides drives turbines. A tidal barrage (a kind of dam) is built across estuaries, forcing water through gaps. In the future underwater turbines may be possible out at sea and without dams. Ideal for an island such as the UK. Potential to generate a lot of energy. Tidal barrage can double as a bridge, and help prevent flooding. Construction of barrage is very costly. Only a few estuaries are suitable. Opposed by some environmental groups as having a negative impact on wildlife. May reduce tidal flow and impede flow of sewage out to sea.
Wave The movement of seawater in and out of a cavity on the shore compresses trapped air, driving a turbine. Ideal for an island country. More likely to be small local operations, rather than done on a national scale. Construction can be costly. May be opposed by local or environmental groups.
Geothermal In volcanic regions it is possible to use the natural heat of the earth. Cold water is pumped under ground and comes out as steam. Steam can be used for heating or to power turbines creating electricity. Potentially infinite energy supply. Used successfully in some countries, such as New Zealand and Iceland. Can be expensive to set up and only works in areas of volcanic activity. Geothermal and volcanic activity might calm down, leaving power stations redundant. Dangerous elements found underground must be disposed of carefully.
Hydrological or Hydroelectric Power (HEP) Energy harnessed from the movement of water through rivers, lakes and dams. Creates water reserves as well as energy supplies. Costly to build. Can cause the flooding of surrounding communities and landscapes. Dams have major ecological impacts on local hydrology.
Biomass It is generated from decaying plant or animal waste, or organic material and can be burned to provide energy. It is a cheap and readily available source of energy. If crops are replaced, it can be a long-term, sustainable energy source. When burned, it gives off atmospheric pollutants, including greenhouse gases.
Wood Obtained from felling trees, burned to generate heat and light. A cheap and readily available source of energy. If trees are replaced, wood burning can be a long term sustainable energy source. When burned, it gives off atmospheric pollutants, including greenhouse gases.

Exam tip

Make sure you know what types of energy are renewable and non-renewable. It is important to remember that biomass and wood are only renewable if the trees and crops are replanted. Many people fall into the trap of thinking that bio means renewable - it doesn't!