Module 3 - Energy Renewable Energy

? Onshore wind farm and small roof mounted wind turbine The wind turns these turbines round to generate electricity. The larger the turbine, the more electricity can be generated on a windy site. Little ones on houses do not generate much electricity.

? Offshore wind farm Britain is lucky to be an island with a lot of potential for off shore wind. It is more expensive to build wind farms at sea, because they have to be extra strong, and the electricity has to be transported safely back to land through underwater cables.

? Solar water heating panels These panels use the heat from the sun to heat water. If everyone in Britain had solar water heating panels, we’d get 50% of our hot water! Not for central heating though – we don’t have big enough roofs for the number of panels we’d need.

? Solar photovoltaic panels ‘Photo’ means light, and ‘Voltaic’ means electricity. These panels convert light into electricity.

? Tidal power The movement of the tide as it goes in and out can be used to generate electricity. There are several different tidal power designs. Some work by building a barrage which floods part of the estuary sometimes to control the flow of water through turbines. This means that the estuary is sometimes flooded and the local wildlife habitat can be destroyed. Tidal stream is different – giant turbines underwater produce electricity as the water moves past with the tide. They produce less electricity than the other design on the same site, but can be put in many more places.

? Hydro Power A dam is built in a valley with a river in it. The river is blocked by the dam and floods to make a reservoir. Gates in the dam can be opened to allow the water to pass through turbines to generate electricity. On a very large scale like in China (much larger than any we have in Britain) they can be very destructive – people have to leave their homes and wildlife habitats are destroyed. When plants and trees covered in flood water decay they release powerful green house gases too.

? Micro Hydro Power Micro hydro also controls the flow of water through a turbine to generate electricity. But it is on a much smaller scale using small rivers and streams and is not environmentally destructive.

? Heat pumps Have you noticed that the inside of your fridge is cold, but the machinery at the back is hot? Ground source heat pumps use the same technology in reverse to provide heating for buildings, using the temperature of the ground exchanged with the temperature of the air to generate electricity.

? Wood stove Wood can be used to heat the rooms in a building and also heat water. Wood stoves can be designed to use logs, or wood chip, or wood pellets. Wood produces C0 2 when it is burned. But if new trees are planted in their place, they will absorb more C0 2 to replace that which is burned.

? Biomass Combined Heat and Power (CHP) In this Combined Heat and Power (CHP) plant, wood chips (biomass) are burned to generate heat and also to generate electricity by passing heat through large turbines.

? Anaerobic Digestion In this plant, organic matter (like food waste, slurry from farms, or biomass crops) is burned without oxygen to generate heat or electricity.