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Geothermal energy uses hot water and steam from deep underground to drive turbines. Radioactive decay of substances like uranium heats up rocks, which may heat water that rises as steam. In some places there may be hot rocks but no water. In this situation, deep wells can be drilled down to the hot rocks and cold water pumped down. The water runs through the rocks where it's heated up and returns to the surface as hot water and steam, where its energy can be used to drive turbines and electricity generators. The advantages are that there are no pollutant gases produced. However, most parts of the world do not have suitable areas where geothermal energy can be exploited.
Finally, you can use solar cells to generate electricity. They convert light energy directly into electrical energy. The advantages are that they can be used in remote areas because they create electricity directly. However, solar cells are expensive and inefficient, so the cost of their electricity is high. But the cost is going down year by year and eventually, everyone will want it.