Only about half of incoming solar radiation makes it to the earth’s surface. The rest is either reflected or absorbed in the atmosphere. Solar energy is the source of all energy on earth, whether stored for millions of years (fossil fuels), causing differential heating of the earth’s crust (which leads to tidal, wind, and geothermal energy), or creating electricity directly through photovoltaic solar panels.
Solar Energy typically refers to the use of solar radiation by humans, and is often used interchangeably with Solar Power, although this is more specifically the production of electricity through photovoltaics.
The term solar energy also encapsulates passive solar design (housing), solar hot water (solar thermal), cooking (solar ovens), water purification (solar stills), and many other uses. These are all practical uses of insolation by human beings.
That’s the definition of solar energy, but it’s really only the beginning…