Geothermal energy focus: Tapping the earth's natural heat

Geothermal energy has been providing heat and power for humans for centuries. The first district heating system was started in France in the 14th Century. It was not until the turn of 20th Century when the first use of geothermal energy for electric power production began. Nowadays, thousands of MW of installed capacity of geothermal systems exists and many countries are turning to it to supplement conventional sources of energy. John W. Lund, Oregon Institute of Technology, USA provides a current overview of the use of geothermal energy worldwide.