Energy Beneath Our Feet: Geothermal Energy

As scientists have been digging deeper into the possibilities for renewable energy, they look to the sun, the wind, and other renewable options for cleaner, greener sources. Another possibility may be right beneath our feet- geothermal energy.
As the name suggests geo stands for earth and therme for heat, so geothermal energy comes from the heat produced by the earth. Beneath the crust of the earth, there are a number of heat-producing layers of rock, minerals, and magma, including the mantle, the outer core, and the inner core. The deeper you dig towards the center of the Earth, the hotter it gets. In fact, the core can reach temperatures of 7,600 degrees Fahrenheit.This heat-which can be harnessed for energy is caused by residual heat from the formation of the Earth, as well as decay of isotopes.

Harnessing Geothermal Energy

There are several other ways to harness the heat of the Earth for energy. Few are listed below.

Direct Geothermal Energy can be accessed in areas where hot springs/geothermal reservoirs are near the surface of the earth. In these areas, hot water can be directly piped in to heat homes or buildings. The used water is then returned to the reservoir for reheating.

Geothermal heat pumps are another method for harnessing geothermal energy. These systems utilize a series of underground pipes, an electric compressor and a heat exchanger to absorb and transfer heat. In the summer, the system removes heat from the house and returns it to the earth. In the winter, the geothermal pump absorbs heat from the ground and transfers it into the house/building.

Geothermal power plants also harness the heat of the Earth through hot water and steam. In these plants, heat is used to generate electricity. There are three main types of geothermal power plants, including dry steam plants, flash steam plants, and binary cycle plants.
How is Geothermal Energy a Renewable Energy Source?

Renewable energy sources, unlike fossil fuels, are virtually unlimited resources. Since the core of the Earth is so hot, and this heat permeates throughout the other layers of the planet, geothermal heat as a source of energy will not deplete. Additionally, geothermal power plants produce just a fraction of the carbon emissions of fossil fuel plants.

As with many types of renewable energy, the initial costs of geothermal energy installment are high. However, studies show that a residential geothermal heat pump can reduce energy bills by as much as 40%, and will likely pay for itself within 5-10 years.