Since the industrial revolution Man has extensively abandoned his dependence on solar energy.  Due to their fundamental needs such as heating homes and drying products, our ancestors relied on sun radiation. They also indirectly enjoyed solar energy when using firewood oven, watermill or plough. (In photo synthesis process for producing complex biological molecule, which is being found in live plants, sunlight has the most effective role.)

Primitive Man took advantage of the fact that limited radiation touching surface of the land turns into wind, rain and plants. Direct radiation of the sun is the most abundant form of energy. Every year around 5.4 million oxajoul of solar energy encounters the highest level of the earth atmosphere, of which 1/3 is reflected into space and 18% is absorbed by atmosphere most of which turns to wind. So 2.5 million oxajoul would remain and reach to the surface of the earth – 6000 times more than global energy consumption in 1990. In other word, total fossil fuel resource from beginning of civilization to present time – oil, coal, and natural gas – are less than 30 days of radiation of sun to the earth. Most of these energy sources quickly turn to heat absorbed by atmosphere and oceans. In the lack of solar energy the heat of our home (while stoves are working) would rich to –240˚c. Statistics suggest that in U.S.A around 40% of supplied energy carriers are consumed in factories and buildings for heating and air conditioning and also in motor vehicles which could severely damage environment and rise climate heat.