Geothermal energy is heat that is stored deep inside Earth. It’s a renewable energy source that is produced naturally by Earth. Deep in the center of the earth, heat energy is produced due to nuclear reactions similar to our sun! Slowly that heat travels up from the core to the surface of the earth. However during that journey the heat cools as it reaches closer towards the surface and eventually when it reaches the crust, it radiates into space.
The interior of the earth, where nuclear reactions happens, sending heat towards the surface.
To harness this energy and make it useful to human, it first needs to be converted into electrical energy. In order to obtain the heat in the earth, two holes are drilled deep down into a layer of hot rocks near the mantle. One of the two holes is used to pump down cold water to the hot rocks, where the water gets heated. While the other hole allows the hot water or the steam to travel back up towards the surface, under its own pressure. At the surface the steam or the hot water is passed through a heat exchanger. The heat energy is then used to spin turbines which change the spinning movement into electricity. Soon, the electric charge goes through a transformer, where the voltage is increased and then it is eventually sent down power lines.