Solar energy, the radiation of light and heat from the Sun, has been harnessed by humans since ancient times by using a range of ever-evolving technologies. Solar radiation, along with secondary resources of solar energy such as wind and wave power, water power and biomass, makes up most of the renewable energy available on Earth. Only a very small fraction of the available solar energy is used. Solar power means generating electricity based on a heat engine and photovoltaic battery. The use of solar energy is limited only by human ingenuity. A partial list of solar applications for space heating and cooling through solar architecture, through distilled drinking water and disinfection, daylighting, solar hot water , solar cooking, and high temperature process heat for industrial purposes. To collect solar energy, the most common way is to use solar panels.Solar technology is widely described as either passive solar or active solar depending on how they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness energy. Passive solar techniques include orienting a building toward the Sun, selecting materials with favorable heat volume or scattered light properties, and designing natural air circulation spaces. .