Geothermal energy literally means the heat from within the earth. The energy is contained in the concentrated heat that the earth's core radiates. The temperatures at the core may be as high as 7000°C. Although the earth's crust, which varies in thickness, does generate a little heat, it also protects the surface from the heat from the core. This heat often rises and collects just under the earth's surface. It is only then that the heat can be drawn and utilized as a source of energy.

How does this heat collect near the earth's surface?

A layer called the mantle, consisting of magma and rocks, divides the earth's crust from its core. The temperature in the mantle is approximately 3600° C. the earth's crust is broken into what are known as plates. The constant movement of mantle rock may cause these plates to drift. When these plates drift apart molten magma rises into the cavity and solidifies, forming a new crust. When plates collide, the friction forces the plate to sink into the magma below, thus melting. Clouds of this molten magma often rise and break through the crust, bringing the heat close under the surface. Some of this magma reaches the surface forming volcanoes, but most of it remains below, creating vast underground areas of fiery magma, crust and rocks.

In some areas, water seeping through fissures in the crust, comes into contact with these hot rocks, and gets heated. Hot springs form in those areas where the water makes its way to the surface again. However, this hot water may remain underground and form geothermal reservoirs. These reservoirs can provide a powerful source of energy.

Geothermal energy, in addition to being immensely useful, is also fairly easy and affordable to tap. Anything from complex power stations to simple pumping mechanisms can be used. It can, on many occasions, serve as an alternative to fossil fuels.

Heating Your House

There are now companies that will survey your land and setup an entire system that will tap into your free geothermal energy under your feet so you can heat and cool your house throughout the year. It's quickly becoming a popular alternative to more traditional methods of heating/cooling your home.

Powering a Country

Many countries have succeeded in tapping geothermal energy, making use of it in homes, buildings etc. Especially in a cold region like Iceland, geothermal heat is used to maintain a level of warmth in homes, buildings. In fact, in Iceland, entire districts are heated with geothermal energy. The world's largest geothermal system for district heating is in Reykjavík in Iceland. Even in the United States, Geothermal energy is being effectively used to supply electricity as well as a natural heating system in individual homes.