What is Geothermal Energy?

Study Notes

Geothermal energy is heat energy located under the Earth's surface, often found near tectonic plates, where movements allow heat to push through from the Earth's core.
This energy can be carried to the surface and used for heat and electricity.

Humans have been using geothermal energy for at least 10,000 years, with evidence of indigenous peoples using hot springs for healing, cooking, and escaping harsh weather.
Ancient Greece and Rome also used hot springs medicinally and for heating buildings.

The two primary uses of geothermal energy are for heating and generating electricity.
Geothermal heat pumps can directly heat and cool buildings by using liquid cooled and heated beneath the Earth's surface.
Geothermal sources can be used to generate electricity by rotating a turbine with steam from heated water underground.

Geothermal energy is renewable since heat is constantly produced at the Earth's core as radioactive isotopes decay.
However, individual geothermal plants can become cold if the heat is used more quickly than it can be replenished.

There are three main types of geothermal power plants: dry steam, flash steam, and binary cycle.
Dry steam plants access existing steam underground and use it to spin turbines that generate electricity.
Flash steam plants generate steam by pumping high-temperature water into an area of low pressure.
Binary cycle plants conserve water by pumping it underground to be heated, then using it to heat an organic liquid with a lower boiling point than water.

Geothermal heat pumps operate on a smaller scale than power plants and are used for heating and cooling buildings.
Water or another liquid is piped underground, where it is either heated in the winter or cooled in the summer.
Geothermal heat pumps generally last for 20 to 25 years, longer than conventional heat systems.

Renewable and constantly replenished as long as the Earth is inhabitable.
Only emits water vapor, making it a sustainable and carbon-friendly option.
More stable than other renewable resources, unaffected by seasonal changes.
Cheaper than fossil fuels, requiring smaller land and resources.
Can be used for small or large applications, adapting to various conditions and requirements.

Injecting water into the Earth can cause localized earthquakes.
Power plants can cause the ground to slowly sink as reservoirs beneath are disturbed.
Limited to locations near tectonic plates, making it difficult for some areas to access.
High initial cost to start a geothermal power plant, making it challenging for developing countries to afford.
Risk of toxic chemicals in the water being pumped underground, potentially contaminating nearby water supplies.