Solar energy begins with the sun. Solar panels, also known as photovoltaics, are used to convert light from the sun, which is composed of particles of energy called "photons", into electricity that can be used to power elecrical loads. Light from the sun is a renewable energy resource which provides clean energy, produced by solar panels.The development of solar energy goes back more than 100 years. In the early days, solar power was used primarily for the production of steam which could be used to drive machinery.