Although renewable energy sources such as solar and wind power tend to receive the most public attention, geothermal energy is growing in popularity as a green energy source throughout Europe. Germany, for example, is working towards providing all of the country's energy needs from geothermal energy. The UK, although not as ideally situated as Germany in terms of geology, still contains sufficient geothermal potential that officials estimate that this type of energy could in time supply one fifth of the UK's total power.
What is Geothermal Energy?
The deeper you progress towards the centre of the Earth, the hotter it gets. There is a lot of hot water and steam located deep under the Earth's surface that is contained in geothermal reservoirs and is accessible by drilling. Near the Earth's surface, the ground maintains a relatively constant temperature of approximately 10 to 16 degrees Celsius year-round. The heat contained in both of these areas of the Earth is accessible in order to supply energy that can generate electricity or directly heat and cool buildings.
Geothermal plants can exist anywhere there are reservoirs of steam or hot water in the ground. In Europe, the underlying geology of the region means that most geothermal plants tap into the heat stored in shallow ground, which is the upper 3 meters of the Earth's surface. Even though 10 to 16 degrees Celsius may not seem very hot, use of a heat exchanger makes these temperatures sufficient for heating buildings in the winter or cooling them in the summer. This type of geothermal heat is harnessed with a geothermal heat pump system for heating and cooling buildings. The geothermal heat pump system consists of a heat pump, an air delivery system, and a heat exchanger. The heat exchanger is a series of pipes that is the key to this energy source, as it allows the heat to be moved between water and air. The heat pump can then transfer the heat from the water in the pipes to the air in the building's air delivery system. In the summer, the heat pump can move heat from the indoor air system into the heat exchanger, and the resulting hot water can be recycled.
The other type of geothermal energy is direct geothermal energy that comes from hot springs or geothermal reservoirs near the Earth's surface. In this case, hot water is pumped from these reservoirs into buildings to supply heat via a heat exchanger, and the used water is returned to the earth to be naturally reheated and reused. Instead of being pumped directly to buildings, this type of geothermal energy can also be used to generate electricity in a power plant. These geothermal plants are much less common in Europe than heat pump systems due to the geology of the region.
Advantages and Disadvantages
- Completely Renewable.
Harnessing the Earth's heat for energy does not diminish the heat that is stored in the Earth.
- Not as Noisy as Wind Power.
Unlike wind farms, geothermal plants don't create vibrations in the air or a loud sound that prevent people from living near them. In this way, geothermal energy is more space-effective than wind power.
- More Available than Solar Power.
Unlike solar power, geothermal energy is still present and available at night and during bad weather. Because the amount of time available for it to be harvested is greater, geothermal energy is also a more efficient energy source than solar power.
- Dependent on Geology.
The availability of geothermal energy varies depending on the geology of the location, making some parts of the country or continent more favourable for geothermal plants than others are.
Author bio
Peter Finchley is a keen observer of the environment who loves solar gadgets and sells solar powered Christmas Fairy Lights sold through his online store.