Geothermal Energy – energy from the Earth 1.Cold water is pumped below the ground. 2.Hot rocks heat the water, turning it into steam. 3.The steam is used to generate electricity. + Renewable + No pollution, because nothing gets burned + Doesn’t damage the environment + No fuel cost + Reliable – Very few places in the world where you can do this – Costs a lot of money to drill deep into the ground – Can sometimes releases harmful gases – Possible earthquake or surface cracking when drilling. Deep underground, the Earth’s rocks are naturally very hot. We can turn their heat energy into electrical energy to use in our homes – we call this ‘geothermal energy’.

Wave Energy – energy from sea waves +Renewable +No fuel cost +Reliable +No pollution, because nothing gets burned The sea’s waves have kinetic energy. Using machines that bob up and down in the waves, this energy can be turned into electrical energy which we can use in our homes. – Need lots of machines to get a reasonable amount of energy – The machines costs a lot of money – The machines can look ugly – The machines can be damaged by storms – Can affect marine life wave energy machines bobbing up and down in the waves

Hydroelectric Energy – energy from rivers + Renewable + No pollution, because nothing gets burned + We can store the water up high, and then whenever we need the energy we can let the water out +No fuel cost +Reliable +Immediate response to change in electricity demand +Cheap The water flowing in a river has kinetic energy. We can turn this into electrical energy to use in our homes. We usually need to build a dam, and let the water flow through it gradually. – Costs a lot of money to build a dam – The dam can ruin the local environment, because it changes where the water naturally flows. Some animals and plants may die. –Can only be located in suitable places

Tidal Energy – energy from sea tides 1.At high tide, we trap the water behind a dam. 2.At low tide, the water is released, and its energy is used to generate electricity. + Renewable + No pollution, because nothing gets burned + Reliable, because there are always two tides every day + Cheap to run, once it’s built – Costs a lot to build the dam – The dam may cause local flooding If you’ve ever been to the coast, you may have noticed that the sea level goes up and down, because of tides. When the tide is high, the water has lots of gravitational potential energy, which we can turn into electrical energy to use in our homes.

Solar Energy – energy from the Sun +Renewable +No CO 2 or other air pollutants +No fuel cost +Easy to install +Little environmental impact when located on buildings – Solar cells and solar panels are expensive – Only works if it’s sunny! The Earth gets heat and light energy from the sun all the time. Can we use it – yes we can! The Sun’s energy can either be: 1.changed into electrical energy to use in homes, using solar cells; 2.or used to heat water for homes, using solar panels.

Wind Energy – energy from the wind + Renewable + No pollution, because nothing gets burned + Turbines are quite cheap and easy to build, so they can be used even in poor countries – Turbines can be ugly and noisy – Only works if it’s quite windy! If the wind stops, you get no energy. – Can be a threat to birds and bats. – Can only be located in suitable places Using wind turbines, we can turn the kinetic energy of the wind into electrical energy which we can use in our homes. This is ‘wind energy’.

Biomass Energy – energy from plants (Biofuel) 1.Trees absorb the sun’s energy. The trees change this energy into chemical energy, which they store inside themselves. 2.When we burn wood, we turn this energy into heat, which is useful for cooking and heating. + Renewable – as long as we keep planting trees to replace the ones we cut down + Doesn’t need any special equipment, so it can be used very easily, even in poor countries – Large areas of land are needed to grow enough trees – Releases CO 2 – Loss of habitat and space to grow crops due to large amount of land needed. The chemical potential energy stored in things that were once alive (e.g. trees) can be turned into heat energy by burning them. (We can also turn it into electrical energy to use in our homes.)

Nuclear Energy + No pollution, because nothing gets burned Can produce large amounts of electricity from a small amount of fuel A good way to use up uranium and plutonium, rather than in bombs! + Reliable – Very few places in the world where you can do this, as no one wants it on heir doorstep. – Can be very dangerous if things go wrong – Waste is radioactive for thousands of years. The main nuclear fuels are uranium and plutonium. In a nuclear power station nuclear fuel undergoes a controlled chain reaction in the reactor to produce heat - nuclear to heat energy. heat is used to change water into steam in the boiler. the steam drives the turbine (heat to kinetic energy) this drives the generator to produce electricity - kinetic to electrical energy.

Fossil Fuel Energy 1.this heat is used to change water into steam in the boiler. 2.the steam drives the turbine - heat to kinetic energy 3.this drives the generator to produce electricity - kinetic to electrical energy. + Industry set up already to process this energy + Easy to use ‒ Will run out someday – non renewable ‒ Releases CO 2 and other air pollutants ‒ Prices are rapidly increasing. ‒ New drilling by fracking can cause environmental problems to water and animals in surrounding area. In a thermal power station fuel such as coal, oil or gas is burned in a furnace to produce heat - chemical to heat energy.