Turning hot water into energy

There are two ways to use hot water as a sustainable energy:

Heating buildings

Firstly, you can use the hot water for heating in buildings; this is known as a district heating scheme. In fact, the capital city of Iceland, Reykjavik, uses a district heating scheme for 95% of the buildings in the city.

Geothermal power station

Alternatively, you can use the hot water in a geothermal power station. In a normal power station a fuel is burnt to in order to heat water, which turns to steam, and then drive turbines which make the electricity.

With a geothermal power station you do not need to burn any fuel in order to heat the water. Instead, the steam comes directly from the hot water underground and turns the turbines. So with no fuel being burnt it’s easy to see why geothermal energy is much better for the environment than fossil fuels.

Advantages of geothermal energy

Geothermal energy is continually produced within the Earth so will not run out
Geothermal energy does not produce pollution
Any waste steam or water from a geothermal power plant can be put back into the Earth to be re-used

Disadvantages of geothermal energy

Harmful gases and minerals can escape from the borehole and it can be expensive and difficult to dispose of these gases
It is difficult to find a location for geothermal energy
A geothermal borehole can ‘run out of steam’ and can be unusable for decades if its usage is not carefully managed

Geothermal energy in the UK

As the UK does not sit on a tectonic plate boundary, the heat inside the Earth is too deep to successfully generate electricity from it. In the UK geothermal energy is fairly rare and the UK does not currently have any geothermal power stations.

However, it is possible to use geothermal energy for district heating schemes as they do not require the water to be as hot as for a geothermal power station.

An example of this is in Southampton, where heat from a borehole is used to power buildings in a 2km radius of the borehole. This includes the Civic Centre buildings, West Quay shopping centre, multiple office buildings and over a thousand residential houses.