How Does Geothermal Energy Work?
It's being used around the world to heat homes and provide electricity. How does geothermal energy work? While some uses of geothermal energy require drilling deep within the Earth, others are just below the surface.
How Does Geothermal Energy Work:
Three Primary Uses of Geothermal Energy
Direct Use of Geothermal Energy
Mineral rich water from springs and reservoirs has been used since ancient times. Hot springs were traditionally used in common ways, such as bathing and cooking. Various cultures believed the waters had healing properties.
Another type of direct use of geothermal energy is through a district heating system. Hot water located near the Earth's surface is pumped out of the ground and used to heat buildings. The water is piped directly into buildings and warm air is circulated.
Iceland has been using geothermal energy to heat homes and buildings since 1930. The world's largest district heating system provides heat for 95% of the buildings in Reykjavik, Iceland.
Electricity from Geothermal Power Plants
Geothermal power plants use steam to generate power. Energy is processed in three different ways.
- Dry steam reservoirs primarily produce steam instead of water. Steam is brought through pipes from below the Earth's surface. The dry steam is used directly to power the plants turbines.
- Flash steam plants are the most common type of geothermal power plants. These plants use hot water from deep below the Earth's surface. High pressured hot water is sprayed into a tank and converted into steam. The steam powers generator turbines. When it cools, steam condenses to water. The water is put back in the ground, reheated by the Earth, and used again.
- Binary cycle power plants use water from below the Earth's surface to heat a second liquid. Steam from this second working liquid is used to power the plants turbines.
There are several advantages of using geothermal energy for electricity. Geothermal plants do not burn fuel to manufacture steam, so their emission levels are very low. Because a geothermal power plant sits directly on top of its energy source, fuel does not have to be transported. Economic benefits from geothermal energy stay local, and can be an affordable way to help developing countries grow.
Geothermal Heat Pumps
Geothermal heat pumps are used to heat and cool buildings. They can also be used to warm water. Although temperatures above ground can change drastically from season to season, below ground temperatures are relatively constant all year long.
In the winter, geothermal heat pumps transfer heat from the ground to buildings. In the summer, the opposite occurs. Heat from buildings is transferred to the ground. The ground works as a heat source in colder months and a heat trap in warmer months.
|
