Geothermal Energy
What is geothermal energy?
Geothermal energy is natural energy which comes from the
heat of the Earth’s core. Have you ever seen pictures
of a volcano or a geyser? If so, then you’ve seen
examples of geothermal energy in action! It has been used
for thousands of years in some countries for hot water,
cooking and heating.
"Geo" means "from the Earth," and "thermal" means "heat," so
this type of energy is found under the Earth’s surface.
The hot lava from a volcano comes from underground heat – and
we can use that same type of heat in our homes.
Geothermal energy is a renewable energy source because
the heat is continuously produced inside the earth.
Geothermal energy throughout the world
Deep within the Earth it is very hot and when water flows
over hot rocks, hot water and steam are created and escape
to the Earth's surface. In places like Iceland, Russia
and New Zealand, bubbling mud pools, hot springs and geysers
are examples of geothermal energy. Volcanoes are very violent
examples of this type of energy.
The hot water and steam created underground can be used
to create electricity (by turning turbines) to heat homes
and other buildings. The steam is collected, and used to
power a generator, in the same way it is used in a coal
fired power station.
Around the world people also swim in warm natural springs
to help soothe body aches and pains.
Geothermal energy in the UK
Although the heat from deep within the Earth’s core
can be used in some places around the world, in the UK,
we can make use of the fact that just a few metres below
the ground there is a constant temperature between 10-12°C.
For most areas, this means that soil temperatures are usually
warmer than the air in winter and cooler than the air in
summer.
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| This picture shows the pipes underground
in a Ground Source Heat Pump |
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| This shows a Ground Source Heat Pump |
Ground source heat pumps use the Earth's constant temperatures
to heat and cool buildings. The heat pump is a device that
moves heat from one place to another. Some very familiar
ones are fridges and air conditioning units.
Some heat pumps use pipes to take the heat from the ground
to the building in winter and from the building to the
soil in the summer. These can be fitted vertically where
a hole is drilled deep down (a borehole) or horizontally
where long trenches are dug just a few metres underground
in a field or garden (ground loop).
One thing to remember about heat pumps is that they use
electricity to change the heat from the ground into heat
which we can use in our homes and schools.
As well as ground source heat pumps there are also air
source heat pumps which, as the name suggests, work by
taking heat from the outside air and turning it into energy
for a comfortable temperature inside the house as well
as supplying the energy needed for hot water.
Advantages:
-
The energy from the Earth is a renewable resource.
- Most of the equipment that is fitted with a heat pump is
underground which means that it is quiet.
- The technology is very energy efficient so hardly any of
the energy is wasted.
Disadvantages:
- Heat pumps can take up space underground if they are fitted
horizontally.
- Heat pumps use electricity which produces carbon dioxide.
However a renewable electricity source like Eco Energy
or a wind turbine or solar panels can provide their own
renewable electricity.
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