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| | | | | | | Solar. | | | | | The sun provides us with an endless supply of energy. Solar energy uses the sun's radiation to produce electricity in two ways – solar thermal and photovoltaic (PV). It is already being used to provide essential power for many types of equipment being used in both remote and urban areas across the country. | | | | | | | | | | Solar thermal is the collection of the sun's radiant energy (via specially designed collectors) to produce heat, generally for water heating. | | | | | | | | | | Photovoltaic systems convert the sunlight to electricity through the use of photovoltaic cells, using semiconductor technology where "waste" silicon from the computer chip industry is generally used as the semiconductor material. | | | | | | | | | | Much of the energy that we currently use for heating, lighting and air conditioning can be saved simply by designing buildings to make maximum use of the sun. | | | | | | | | | | | | |
| | | | | | | Wind. | | | | | This form of clean renewable energy, which emits no air pollution, is harnessed using wind turbines or windmills to create electricity. Wind turbines already provide a small, but growing percentage of the UK's electricity, and are used successfully all around the world. Wind turbine technology has greatly improved over the last ten years, making wind turbines quieter and more efficient so that electricity generated from the wind is now often competitive with traditional coal-fired and nuclear power stations. Wind power is the world's fastest growing energy source and in the future, much of our electricity could come from coastal and offshore wind farms. | | | | | | | | | | | | |
| | | | | | | Geothermal. | | | | | Geothermal energy comes from hot magma deep beneath the earth's surface. In some parts of the world steam comes to the surface and can be used to run steam turbines to produce electricity directly. In other places water can be pumped down and heated by the rocks to make steam. | | | | | | | | | | Low-to moderate temperature (20°C to 150°C) geothermal resources are used to provide direct heat and hot water for homes and industry, while the high temperature (above 150°C) geothermal resources are used in electric power generation. | | | | | | | | | | Geothermal plants are very economical and produce only one-sixth of the carbon dioxide that a natural gas fueled electrical generating power plant produces. | | | | | | | | | | | | |
| | | | | | | Biomass. | | | | | Biomass plants burn organic material, such as wood and agricultural/animal waste, to produce energy. This clean, renewable process uses two methods of converting biomass to electricity. | | | | | | | | | | Solid biomass fuels are burned in a broiler. The fuel turns to steam which is then used to turn a turbine generator to produce electricity. The second method involves gasifying the fuels to be burned and used as electricity. | | | | | | | | | | As plants grow they absorb carbon dioxide (the main gas responsible for climate change) which is then released when the plants are burnt. So using biomass does not add any extra carbon dioxide into the atmosphere. | | | | | | | | | | | | |
| | | | | | | Hydro. | | | | | Although most of the possible sites for large hydropower stations in the UK have already been developed, there is a large potential for smaller schemes, which have a minimal impact on the local environment and surrounding ecosystem. Hydroelectric plants less than 30 megawatts (MW) in size are considered small-scale hydro and qualify as a renewable resource. | | | | | | | | | | Rapidly moving water is directed through tunnels to rotate turbines, creating mechanical energy. This energy is converted to electric energy by a generator. Unlike other energy sources such as fossil fuels, water is not destroyed during the production of electricity and it can be reused for other purposes. | | | | | | | | | | Water turbines presently provide over 1% of the UK's electricity. | | | | | | | | | | | | |
| | | | | | | Wave. | | | | | Many different devices have been designed over the years to try and capture some of the power of this huge energy resource. One such device on the isle of Islay, off the West Coast of Scotland has recently started generating electricity. Waves hitting the shore are channeled into a large tube to power a specially designed turbine. With the proper support, wave power could provide a significant proportion of the UK's electricity needs in the future. | | | | | | | | | | | | |
| | | | | | | Tidal. | | | | | Tidal power has been used in Britain since the time of the Doomsday Book, which records the existence of over 5,000 tide powered mills. An advantage of tidal power over other renewable energy sources such as wind or solar power, is that it is very predictable. | | | | | | | | | | One way to capture tidal energy is to build a barrage across an estuary, storing water behind it as the tide rises and then releasing the stored water through turbines at low tide. Several sites around the UK could be suitable for this type of tidal system, the largest being the Severn Estuary. | | | | | | | | | | An alternative, is to use 'marine current turbines', which work like underwater wind turbines, harnessing tidal currents instead of the winds. | | | | | | | | | | | | |
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