Heat has been radiating from the center of the Earth for some 4.5 billion years. At 6437.4 km (4,000 miles) deep, the center of the Earth hovers around the same temperatures as the sun's surface, 9932°F (5,500°C) (Figure 1). Scientists estimate that 42 million megawatts (MW) of power flow from the Earth’s interior, primarily by conduction
Geothermal energy is a renewable resource. One of its biggest advantages is that it is constantly available. The constant flow of heat from the Earth ensures an inexhaustible and essentially limitless supply of energy for billions of years to come.
Figure 1: Earth’s Temperatures