Solar power describes a number of methods of harnessing energy from the light of the Sun. Many technologies have been developed to make use of solar radiation. Some of these technologies make direct use of the solar energy (e.g. to provide light, heat, etc.), while others produce electricity. solar power is pollution free during use. Production end wastes and emissions are manageable using existing pollution controls. Solar powered calculators are the most popular promotional product, as more and more products are using solar cell power.