Further reading:
Geothermal facts Geothermal resource page.

Last Updated May 2005

            The earth was formed a long time ago (about 4.5 billion years ago).  In its infancy it wasn't a very nice place to live.  Mostly it consisted of a giant ball of molten rock, some noxious gas and when the sun wasn't out the bitter cold of space (no atmosphere yet).  But a long time later we have this nice crust with all the little plants and animals on it.  But deep below the ground there still lives that old ball of fire.  The center of the earth is HOT, 5000-7000 degrees C.  Fortunately for us, the center of the earth makes our planet volcanically active.   This in turn helped to form our atmosphere and allowed us all the develop.  When water seeps down into cracks in the earths crust it interacts with this hot core.  This causes the lovely show at Old Faithful in Yellowstone national park, and all the nice hot springs all over the world.  In other places there is just a lot of dry hot rocks below us.  But either way (water heated by the earth, or hot rocks) this heat can be captured for energy.  If you have lots of steam and hot water coming up out of the earth (like in Iceland) you can capture this steam and use it to create electricity.  If however you live where there isn't lots of steam shooting out of the ground you can still get energy from the earth.

GEOTHERMAL AND YOUR HOME

            At a certain depth below the earth the earth is always about 50 degrees F.  If you dig a big hole and put a long pipe into it you have yourself a geothermal heat exchanger.  If you pump out 50 degree water you can use it to cool your home in the summer, and conversely you can use it to heat your home in the winter, by using a heat exchanger to remove heat from the water.  water in the winter.  If you are careful and don't pump too much water out, and don't put too much hot water back into your pipe in the summer, you have an unlimited heating and cooling device for your home.   

GEOTHERMAL FOR BIGGER PROJECTS    

            Places like the Philippines get as much as 27% of there power from geothermal.  Large scale geothermal plants have been built in many countries and on all continents except Antarctica.  Iceland has been using geothermal plants for many years now, as have several sites in California.  With proper sighting and usage control geothermal is an energy source that is nearly infinite.