From
http://www.conserve-energy-future.com/Advantages_Disadvantages_GeothermalEnergy.php
1. Significant Cost Saving : Geothermal energy generally involves low running costs since it saves 80% costs over fossil fuels and no fuel is used to generate the power.
2. Reduce Reliance on Fossil Fuels : Dependence on fossil fuels decreases with the increase in the use of geothermal energy. With the sky-rocketing prices of oil, many countries are pushing companies to adopt these clean sources of energy.
3. Environmental Benefits : Being the renewable source of energy, geothermal energy has helped in reducing global warming and pollution. Moreover, Geothermal systems does not create any pollution as it releases some gases from deep within the earth which are not very harmful to the environment.
4. Direct Use : Since ancient times, people having been using this source of energy for taking bath, heating homes, preparing food and today this is also used for direct heating of homes and offices.
5. Job Creation and Economic Benefits : Geothermal energy on the other hand has created many jobs for the local people.
And here's some large infographic GIS pictures that you should click on to get the full effect of:
Favorable sites for Geothermal development:
[img]http://www.nrel.gov/gis/images/geothermal_resource2009-final.jpg[img]
Current utilization of geothermal by state:
