Differentiated Materials ENERGY RESOURCES – KS3 Differentiated Materials

Key Words Energy – being able to do work. e.g. food gives us energy, so that we can move Fuel - Fuel is anything that is burned or altered to obtain energy Fuel gauge

Solar power Most of the Earth's energy comes from the sun Solar power is energy from the sun There are two main ways that we use the Sun's energy 1. Solar Cells 2. Solar water heating

Why Use Solar power? Advantages Solar energy is free - no fuel, no waste or pollution. In sunny countries, easy to use in remote places Good for low-power uses such as solar powered garden lights and battery chargers Disadvantages Doesn't work at night. Very expensive to build solar power stations. Can be unreliable unless you're in a very sunny place Solar energy is renewable because the sun is always there

Energy from fossil fuels Fossil fuels are coal, oil and gas Coal oil and gas Fossil fuels were formed from dead plants and animals over millions of years. fossils

Energy from fossil fuels Fossil fuels have formed over millions of years. Plants and animals died and were immediately covered by sediment in seas or swamps. After millions of years of pressure and heat (900C to 1200C), these remains turned into COAL, OIL and NATURAL GAS. Coal comes mainly from dead plants, like trees, falling into swamps. Oil and gas occur together and were formed from both plants and animals being buried. When we burn fossil fuels we’re using the sun’s energy that has been stored as chemical energy underground for millions of years.

How ‘fossil fuel’ power stations work: Coal is crushed to a fine dust and burnt. Oil and gas can be burnt directly. www.vauxhallsociety.org.uk

Why use fossil fuels to make electricity? Advantages Electricity can be generated fairly cheaply. Transporting oil and gas to the power stations is easy. Gas-fired power stations are very efficient. A fossil-fuelled power station can be built almost anywhere.   Disadvantages Pollution. Burning any fossil fuel produces carbon dioxide, which contributes to the "greenhouse effect", warming the Earth. Burning coal produces more carbon dioxide than burning oil or gas. Mining coal can be difficult, dangerous and ugly. Coal-fired power stations need huge amounts of fuel. Fossil fuels are a non- renewable energy resource. Once we've burned them all, there isn't any more and our use of fossil fuels has nearly doubled every 20 years since 1900. This is a particular problem for oil, because we also use it to make plastics and many other products.

Wind power Wind power also comes from the sun; winds blow because the Sun warms our atmosphere. Warm air tends to rise, and winds are due to other air moving in to replace it. The wind blows the propeller round, which turns a generator to produce electricity We tend to build many of these towers together, to make a "wind farm" and produce more electricity. The more towers, the more wind, and the larger the propellers, the more electricity we can make

Why use wind power? Advantages Wind is free. Produces no waste or greenhouse gases. The land beneath can usually still be used for farming. Wind farms can be tourist attractions. A good method of supplying energy to remote areas Disadvantages The wind is not always predictable - some days have no wind. Suitable areas for wind farms are often near the coast, where land is expensive. Some people feel that covering the landscape with these towers is ugly Can kill birds. Can affect television reception if you live nearby. Can be noisy.   Wind power is renewable. Winds will keep on blowing.

Hydro-electric power Hydro-electric power is generated from falling water. Nowadays there are many hydro-electric power stations, providing around 20% of the world's electricity. How it works: A dam is built to trap water, usually in a river valley. Water is allowed to flow through tunnels in the dam, to turn turbines and thus drive generators to produce electricity. (http://www.wvic.com/hydro-works.htm) 

Why use Hydro-electric power? Advantages Once the dam is built, the energy is almost free. No waste or pollution produced. Much more reliable than wind, solar or wave power. Water can be stored above the dam ready for when it is needed. Hydro-electric power stations can increase to full power very quickly, unlike other power stations. Electricity can be generated constantly (all the time)

The dams are very expensive to build. Hydro-electric power is renewable. The Sun provides the water by evaporation from the sea, and will continue to do it. Disadvantages The dams are very expensive to build. Building a large dam will flood a very large area upstream, causing problems for animals that used to live there. Finding a suitable site can be difficult – what about the people, plants and animals living there already? Water quality and quantity downstream can be affected, which can have an impact on plant life.

Nuclear Power - energy from splitting Uranium atoms Nuclear power is generated using Uranium, which is a metal mined in various parts of the world. Nuclear power produces around 11% of the world's energy needs, and produces huge amounts of energy from small amounts of fuel, without pollution. electronicsdesigninfo.blogspot.com

Advantages of using nuclear power Nuclear power costs about the same as coal, so it's not expensive. Does not produce smoke or carbon dioxide, so it does not cause pollution. Produces huge amounts of energy from small amounts of fuel. Produces small amounts of waste. Nuclear power is reliable.

disadvantages Although not much waste is produced, it is very, very dangerous. It must be sealed up and buried for many years to allow the radioactivity to die away. Nuclear power is reliable, but a lot of money has to be spent on safety - if it does go wrong, a nuclear accident can be a major disaster. People are increasingly concerned about possible accidents and terrorism. Nuclear energy from Uranium is non-renewable. Once we've dug up all the Earth's uranium and used it, there isn't any more. However, because only small quantities are needed, we have enough for hundreds of years.

Tidal power - energy from the sea How it works: Tidal Barrages These work rather like a hydro-electric scheme A huge dam (called a "barrage") is built across a river estuary. When the tide goes in and out, the water flows through tunnels in the dam. The ebb and flow of the tides can be used to turn a turbine. www.h2bidblog.com

Advantages of tidal power Once you've built it, tidal power is free. It produces no greenhouse gases or other waste. It needs no fuel. It is reliable. Not expensive to maintain. Tides are totally predictable. Offshore turbines are not too expensive

Disadvantages of tidal power A barrage across an estuary is very expensive to build, and affects a very wide area. - the environment and birds. There are few suitable sites for tidal barrages. Only provides power for around 10 hours each day, when the tide is actually moving in or out. Tidal energy is renewable. The tides will continue to ebb and flow, and the energy is there for free.

Geothermal Energy is energy from heat inside the Earth. How it works Hot rocks underground heat water to produce steam. We drill holes down to the hot region; steam comes up, is purified and used to drive turbines, which drive generators to make electricity. Geothermal energy is an important resource in volcanically active places such as Iceland and New Zealand. http://keller.clarke.edu

Advantages Geothermal energy does not produce any pollution. The power stations do not take up much space. No fuel is needed. Once you've built a geothermal power station, the energy is almost free.

Dangerous gases and minerals may come up from underground. disadvantages There are not many places where you can build a geothermal power station. Sometimes a geothermal site may "run out of steam", perhaps for several years. Dangerous gases and minerals may come up from underground. Geothermal energy is renewable. The energy keeps on coming, so long as we don't pump too much cold water down and cool the rocks too much.

Biomass - energy from organic materials Sugar cane can be used to make alcohol, which can be burned to generate power Other solid wastes, can be burned to provide heat, or used to make steam for a power station We can use rubbish, animal manure, woodchips, seaweed, corn stalks and other waste www.animalaid.org.uk aq48.dnraq.state.ia.us

Advantages It makes sense to use waste materials where we can. The fuel tends to be cheap. Less demand on the Earth's resources.   Disadvantages Collecting the waste in sufficient quantities can be difficult. We burn the fuel, so it makes pollution. Some waste materials are not available all year round. Biomass is renewable, as we're going to carry on making waste products. We can always plant and grow more sugar cane and more trees, so those are renewable too.