What is Solar Energy?

The modern world runs on energy. Energy is converted from one form or another, but it is never created or destroyed. Most of the world's main energy sources are based on the consumption of non-renewable resources (petroleum, coal, natural gas, and uranium). While still a small segment of the energy supply, renewable sources such as wind power and solar power are growing rapidly in market share. Closely linked to energy development are concerns about the possible environmental effects of energy use, such as climate changes.

Solar energy is energy from the sun. This energy drives the climate and weather and supports virtually all life on Earth. Heat and light from the sun along with solar resources such as wind and wave power, hydroelectricity and biomass account for over 99.9% of the available flow of renewable energy.

Solar energy is the cleanest and most inexhaustible of all known energy sources. Solar radiation is the heat, light and other radiation that is emitted from the sun. Solar radiation contains huge amounts of energy and is responsible for almost all the natural processes on earth. The suns energy, although plentiful, has been hard to directly harness until recently.

Solar "power" usually means converting the sun's rays (photons) to electricity. The solar technologies could be photovoltaics (PV), or the various concentrating thermal technologies: solar troughs, solar dish/engines, and solar power towers.

Solar "energy" is a more generic term, meaning any technology that converts the sun's energy into a form of energy—so that includes the aforementioned solar power technologies, but also solar thermal for water heating, space heating and cooling, and industrial process heat. Solar energy includes solar daylighting and even passive solar that uses building orientation, design and materials to heat and cool buildings.