Geothermal energy technologies help us harness heat from deep within the Earth to generate power and heat. By using hot thermal water from underground wells, we can create geothermal power plants that provide electricity and warmth. The key to planning these plants is achieving high temperatures. Geothermal co-generation plants have minimal environmental impact as they are mostly underground. Countries like China, the USA, Iceland, and Turkey lead in using geothermal energy. As fossil fuel prices rise, more countries with moderate geothermal resources will find geothermal energy attractive.