Geothermal energy is one of the leading forms of sustainable and environmentally friendly energy production. It is also commonly used for heating and the oldest operating geothermal heating project dates back to the 14th century. However, the idea to generate electricity with geothermal energy didn’t develop until much later. 24 countries in the world now use some form of geothermal energy and that number is expected to increase substantially with further development and success. The United Sates currently has 77 geothermal power plants and leads the world in geothermal energy production. Iceland produces over 30% of their total power from geothermal energy.
How does geothermal energy work?
Geothermal energy relies on heat that has been generated and stored deep in the Earth’s surface. The centre of the Earth is hot enough to melt rock, which creates molten rock (magma). Magma rises to the surface and heats other rocks and underground water. Sometimes this escapes through the surface of the Earth and this is how hot springs and geysers occur. There following are the ways to create geothermal energy.
Direct geothermal energy
This is used where the geothermal energy is close to the surface of the Earth. The heat from hot springs is piped to heat buildings. The water is pumped through a heat exchanger to heat the house and then into the ground to be heated again. If the ground is colder than room temperature a geothermal heat pump can be used to extract heat. This means that space heating is possible almost anywhere. In certain circumstances this can also be used to cool homes if the process is reversed.
Geothermal power plant.
In basic terms hot water and steam from deep under the Earth’s surface is piped up to a power plant. The steam is then used to spin the turbines, which produce energy. The most modern plants can transfer heat into a liquid that turns to steam at low temperatures and therefore they can produce energy from almost any location.