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The then and now guide to wind power How has the use of wind power changed over time? 3 of 33 © Boardworks Ltd 2006

Wind power – word association 4 of 33 © Boardworks Ltd 2006

What is wind power? Wind is the result of the Sun heating the Earth and creating convection currents in the Earth’s atmosphere. Using the wind as a source of energy is not a new idea. Sailing boats and ships, powered by the wind, have been around for thousands of years. Windmills, which used the wind’s power to grind corn, were once a common landmark across Britain. These were the forerunners to modern wind turbines. 5 of 33 © Boardworks Ltd 2006

How do wind turbines work? Wind turbines have large blades that capture the kinetic energy of the wind. This kinetic energy is used directly to turn the turbine and generate electricity. Wind turbines are a source of 'clean energy’ as they do not produce any polluting waste. However, some people consider this source of renewable energy to be noisy and an eyesore. There is also some concern that, if wind turbines are poorly located, they could kill migrating birds. 6 of 33 © Boardworks Ltd 2006

Why are wind farms built? One problem with wind turbines is that individually they do not generate a lot of electricity. They are usually needed in large numbers to have a significant impact on electricity production. A group of wind turbines is called a wind farm. Wind farms require space in open areas, but the land beneath them can also be used for farming at the same time. Offshore wind farms are located at sea. This wind farm is located 10 kilometres from the south-east coast of Ireland. 7 of 33 © Boardworks Ltd 2006

How are wind turbines used effectively? The energy produced by a wind turbine depends on the wind speed. If it is not windy, electricity is not produced, so wind turbines are not a reliable source of electricity. To be effective, wind turbines need to be located in windy areas. Unfortunately, these upland sites are sometimes areas of natural beauty and some people object to building wind farms in such areas. Wind power can be used effectively in remote locations to charge batteries, which can then be used to provide a constant supply of electricity. 8 of 33 © Boardworks Ltd 2006

Wind power – true or false? 9 of 33 © Boardworks Ltd 2006

Opinions on wind turbines 10 of 33 © Boardworks Ltd 2006

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The then and now guide to water power How has the use of water power changed over time? 12 of 33 © Boardworks Ltd 2006

What is hydroelectric power? Hydroelectric power is the electricity that is generated from the kinetic energy of moving water. The power of flowing water has been used for hundreds of years to operate machinery, such as that used to grind corn in mills and factories. However, this was largely replaced by steam power in the Industrial Revolution. Today, hydroelectric power is generated from water flowing in rivers or in man-made installations, were it flows from a high-level reservoir down through a tunnel. Currently, only about 1% of the UK’s electricity is from hydroelectric power. 13 of 33 © Boardworks Ltd 2006

How is hydroelectricity produced? Major hydroelectric schemes involve building a dam across the end of a river valley to form a reservoir. This can be done high up in mountainous areas. Hydroelectric power stations are a very reliable source of electricity and are able to start up production quickly. This is the Glen Canyon dam in Arizona, USA. It has eight generating units, which have an electrical output of up to 1, 042 megawatts. 14 of 33 © Boardworks Ltd 2006

How does a hydroelectric dam work? 15 of 33 © Boardworks Ltd 2006

How is hydroelectricity used effectively? Large-scale hydroelectric power stations must be sited in high, mountainous areas. Damming a river causes the river valley to flood, which can mean that local villages and houses are destroyed. Hydroelectric power schemes also cost a lot of money and take a long time to build. However, they do last a long time and are a reliable source of large amounts of electricity. In the UK, hydroelectricity is generated in Scotland North Wales. The number of environmentally acceptable sites is limited but several small-scale hydroelectric schemes to use the power of our streams and rivers are also in development. 16 of 33 © Boardworks Ltd 2006

Pros and cons of hydroelectric power 17 of 33 © Boardworks Ltd 2006

Reporting of hydroelectric power 18 of 33 © Boardworks Ltd 2006

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What is wave power? Wave power involves capturing the kinetic energy of the oceans and converting it into electricity. Wave power is actually a form of solar energy that is transferred to water by the wind. The rise and fall of waves has the potential to be a an unlimited source of renewable energy. Effective sites for harnessing wave power must have strong waves most of the time, to ensure that enough electricity will be produced. These sites can be on the shore or in deeper, offshore waters. 20 of 33 © Boardworks Ltd 2006

How is wave power used? There are several types of wave power machines that are able to capture wave energy and convert it into electricity. The ‘Limpet’ (Land-Installed Marine-Powered Energy Transformer) on Islay, Scotland, is the world’s first commercial wave energy device. The low profile of this shoreline unit is designed so that it does not affect coastal views. The Limpet device uses an oscillating column of air and water to generate a maximum output of 500 kilowatts of electricity. 21 of 33 © Boardworks Ltd 2006

How does wave power work? 22 of 33 © Boardworks Ltd 2006

How else can wave power be used? Wave power could make a significant contribution to our energy needs but is still in the early stages of development. A deep-water device tested in Orkney, Scotland is the Pelamis Wave Energy Converter. The first “wave farm” is planned for the coast of Portugal. Another proposed machine is Salter’s duck, which could use wave direction of waves power efficiently. However, only long chains of these units would produce ducks move useful amounts of electricity and up and down these cannot be sited near boats. What are the advantages and disadvantages of wave power? 23 of 33 © Boardworks Ltd 2006

Wave power – true or false? 24 of 33 © Boardworks Ltd 2006

What is tidal power? Tidal power involves harnessing the kinetic energy of tidal waters, which flow twice a day. The tide is the regular rising and falling of the ocean's surface due to the gravitational pull of the Moon, and to a lesser extent the Sun. Tidal power involves building a dam across a river estuary. Water is only able to flow in and out of the estuary through turbines in the dam, which harness the tidal energy and convert it into electricity. Tidal power stations can provide a lot of electricity but building them is expensive and may lead to loss of wildlife habitats. 26 of 33 © Boardworks Ltd 2006

How is tidal power used? 27 of 33 © Boardworks Ltd 2006

How can tidal power be used effectively? Tidal power is a predictable and reliable source of electricity. However, the difference between high and low tides needs to be at least 5 metres to generate practical amounts of electricity. Monthly variations in the height of the tide also affect how much electricity is produced. Tidal power only produces electricity when the tide flows, about 10 hours a day, and should be used with other sources. Worldwide, only around 20 sites have been identified as suitable for tidal power stations. The UK has eight possible sites but, as yet, we do not get electricity from tidal power. 28 of 33 © Boardworks Ltd 2006

Pros and cons of tidal power 29 of 33 © Boardworks Ltd 2006

Glossary l hydroelectric power – Electricity that is produced from the kinetic energy of falling water. l offshore wind farm – A wind farm that is located at sea. l tidal power – Electricity that is produced from the rise and fall of the tides. l wave power – Electricity that is produced from the up and down motion of waves. l wind farm – A collection of wind turbines. l wind turbine – A machine that uses large blades to capture the kinetic energy of the wind and convert it into electricity. l wind power – Electricity that is produced from the kinetic energy of moving air. 31 of 33 © Boardworks Ltd 2006