The sun converts hydrogen into helium (by nuclear fusion) and releases the energy generated during this process in form of light and heat. Within an hour, the sun releases more energy towards the earth than the earth's entire population consumes in one year. Certain solid materials, so called semiconductors, have the ability to generate negative or positive charges under application of light and heat. This generates a direct current, which can in turn be used to drive motors. In case this current has to be fed into the public grid or a load needs to be driven with alternating current, an inverter must be used.