Long before sunlight sustained life on the surface, Earth’s internal heat powered the deep-sea vents where scientists believe life began.
The immense reservoir of heat inside Earth keeps the planet geologically active. But it can also be very useful to humans. Geothermal energy represents a huge and largely untapped source of clean electricity available around the clock. The concept is simple: drill wells down to the heat and use heated water to drive turbines to make electricity.
