Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat.
Different types of renewable energy, their advantages and disadvantages.
| Type of energy | Where it is from | Advantages | Disadvantages |
|---|---|---|---|
| Solar | Energy from sunlight is captured in solar panels and converted into electricity. | Potentially infinite energy supply. Single buildings 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. Potentially infinite energy supply. | Manufacture and implementation of wind farms can be costly. Some local objection and stringent planning regulations mean that implementation is difficult in some areas. |
| Tidal | The movement of tides drives turbines. A tidal barrage (a kind of dam) is built across estuaries, forcing water through gaps. In 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 | Decaying plant or animal waste. An organic material, which can be burned to provide energy, eg heat, or electricity. Examples of biomass energy is rapeseed oil, or wood pellets. | It is a cheap and readily available source of energy. If replaced, biomass can be a long-term, sustainable energy source. | When burned, it gives off atmospheric pollutants, including greenhouse gases. Biomass is only a renewable resource if crops are replanted. |
