Question: How is geothermal electricity renewable?
Answer: Technically you could argue that geothermal isn’t a renewable resource because eventually the heat source will die out. However, this is likely to take millions of years to occur. Most of the heat (90%) present under the crust of the Earth comes from radioactive decay of various isotopes trapped under the surface of the Earth. There is simply so much of these materials like uranium, plutonium, etc that we can consider geothermal energy to be renewable because by the time the core of the Earth and the mantle meet each other due to the cooling of the molten rocks, metals, and other materials the Sun will likely have become a red dwarf and engulfed our planet.
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