The word geothermal includes the word ‘geo‘, which relates to the ground/land part of the earth and ‘thermal‘ which relates to heat.
The radioactive decay of radioactive substances releases heat energy, which heats up the rocks underground.
How geothermal energy works:
1. Water is pumped underground
2. The water pumped down is heated by hot rocks underground
3. The heated water then turns to steam (water vapour), which rises to the surface.
4. Steam is used to turn a turbine
5. The turbine is connected to the generator, which will generate electricity.
Geothermal energy is a great alternative to burning fossil fuels because it does not involve burning fuels, which means that no CO2 is being released and there are no fuel costs. The hot water and steam can even be used to heat buildings.
In the word biofuel, it includes ‘bio‘ which relates to living things (plants in this case) and ‘fuel‘ which is a material you burn to produce heat or power.
So to make biofuels:
1. You grow the plants
2. Then harvest the plants
3. Burn the plants in the power stations
When plants burn, they release carbon dioxide (CO2). However, this is not as harmful because when plants grow. they take in CO2 through photosynthesis. This means when you burn the plants, you’re just releasing the absorbed CO2 and not releasing any extra CO2. This means that biofuels are carbon neutral.