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– Very few places in the

world where you can do this

– Costs a lot of money to drill deep into the ground

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 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

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

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.

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 pollution, because

nothing gets burned– 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.

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’.

1. Wind energy moves wind turbines.

2. The moving turbines cause the movement needed in a generator to produce electricity.

Biomass Energy – energy from plants

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

+ Doesn’t add to the greenhouse effect

– Large areas of land are needed to grow enough trees

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 – energy from Uranium

1. Heat generated from nuclear fission (when an atom splits in two) heats up water to produce steam

2. The steam turns turbines and gives the movement a generator needs to produce electricity.

+ Renewable + Produces huge amounts of

energy from small amounts of fuel

+ Doesn’t add to the greenhouse effect

– Can be very dangerous – a nuclear accident could be a major disaster

– Power stations are big and ugly and expensive to build

The chemical potential energy stored in the metal Uranium, which is found in the ground, is used to provide heat energy inside a nuclear reactor. This heat energy is then turned into electrical energy so that we can use it in our homes.

Fossil Fuels – Coal, oil and natural gas

1. Heat generated from burning the fossil fuels heats up water to produce steam

2. The steam turns turbines and gives the movement a generator needs to produce electricity.

+ At present, generating electricity using fossil fuels is cheaper than using renewable resources.

+ Electricity from power stations is available all the time.

– Releases carbon dioxide which contributes to climate change and Sulphur Dixoide (acid rain)

– Extracting and transporting fossil fuels causes pollution and can change landscapes.

The fossil fuels are coal, oil and natural gas. They are fuels because they release heat energy when they are burned. They are fossil fuels because they were formed from the remains of living organisms millions of years ago.About three-quarters of the electricity generated in the UK comes from power stations fuelled by fossil fuels. To the right is an energy transfer diagram for the generation of electricity from a fossil fuel such as coal.