Solar Energy
Solar energy is energy from the sun. This energy drives climate and weather and supports virtually all life on Earth. Heat and light from the sun, along with solar-based resources such as wind and wave power, hydroelectricity and biomass, account for over 99.9 percent of the available flow of renewable energy.
Solar energy technologies are those that utilize sunshine to produce other forms of energy. These technologies date from the time of the early Greeks, Native Americans and Chinese, who warmed their buildings simply by orienting them toward the sun. Modern solar technologies harness the sun, sometimes in more innovative ways, to provide heating, lighting, electricity and even flight.
The terms solar power and solar energy are often used synonymously but solar power usually refers to photovoltaic (PV) and concentrating solar thermal technologies that convert sunlight into electricity. In the case of solar PV, the process is direct, via silicon-based cells; in the case of solar concentrating thermal, the process involves heating a transfer fluid to produce steam to run a generator. While PV has advantages in terms of simplicity, the high temperatures produced by solar thermal systems also can provide process heat and steam for a variety of secondary commercial applications (cogeneration).
In 1866, the French engineer Auguste Mouchout successfully powered a steam engine with sunlight, which was the first known example of a solar-powered mechanical device. Over the next 50 years, inventors such as John Ericsson, Charles Tellier and Frank Shuman developed solar-powered devices for irrigation, refrigeration and locomotion. The progeny of these early developments are the concentrating solar thermal power plants of today.
