Great Green Idea: Green Energy: How Green is Geothermal Energy?

How Green is Geothermal Energy?

Geothermal is derived from two Greek words; geo, which means the earth and thermal, meaning heat. Geo-thermal energy uses the heat from steam and hot water that is in the earth to provide electricity and warmth. It is an energy source that is considered renewable because both rain and heat in the earth replenish themselves naturally. Learning about the technology available to harness this energy and how it is used will determine whether it is an eco-friendly energy source.

How Geothermal Energy is Produced?

Deep within the earth the temperature is hotter than the surface of the sun. This is because rocks slowly decay into radioactive particles, creating energy that comes from the core of the earth. The earth's core is about four thousand miles below the earth's surface. The intense heat from the core generates magma, or molten rock and other materials, which rise to the earth near the edges of broken pieces of its crust. The magma heats rocks and water that is deep within the earth. These pieces of the earth's crust are called plates. This source of volatile green energy occurs around the world in places where there are lots of volcanoes and earthquakes, such as around the Pacific Ocean.

Geothermal Reservoirs

Areas where the heated rocks and water are most concentrated are called geothermal reservoirs. These areas are located by geologists in several ways. Wells are dug deep into the earth to test the temperature for actual confirmation that a geothermal reservoir is in a particular location. Geologists closely study pictures that are taken from the air and maps to find potential reservoir locations. Measurements of gravity and magnetic fields give a possible indication of the location of a reservoir. In the United States, a good portion of these reservoirs are located in the western part of the country. The state of California has the largest dry steam field in the world and the state has used the most amount of green energy for electricity in the United States since 1960.

Applications for Geothermal Energy

This energy is used to generate electricity by way of green energy from hot water beneath the earth, otherwise known as a hydrothermal resource. There are two types of hydrothermal resources; dry steam and hot water. Around the globe the resource is used to heat homes and businesses. Heating and cooling is also supplied from temperatures near the earth's surface. The method of using hot water is not new; it has been implemented for centuries around the world for hot spring bathing, cooking and heating. It is also used for power plants and heat pumps as well as national park features like geysers.

Eco-Friendly Energy Source

The use of geothermal energy for heating has hardly any negative environmental impact. Since the power plants utilizing this energy don't burn fossil fuels for electricity, the emissions they produce remain very low; as much as 97% less than a fossil fuel plant. Another helpful characteristic of geothermal energy is that the steam and water that was utilized is injected back into the earth. Further, any use of geothermal reservoirs is protected as a natural resource.