Solar power is the flow of energy from the sun. The primary forms of solar energy are heat and light. Sunlight and heat are transformed and absorbed by the environment in a multitude of ways. Some of these transformations result in renewable energy flows such as biomass, wind and waves. Effects such as the jet stream, the Gulf Stream and the water cycle are also the result of solar energy's absorption in the environment.
Solar energy also broadly describes technologies that utilize sunlight. The applications are diverse and date back millennia. The Greeks, Native Americans and Chinese warmed their buildings by orienting them toward the sun. European farmers used elaborate field orientation and thermal mass to increase crop yields during the Little Ice Age. Modern solar technologies continue to harness the sun to provide water heating, daylighting and even flight.The term solar power specifically describes technologies that convert sunlight into electricity or mechanical power. In 1866, the French engineer Auguste Mouchout successfully powered a steam engine with sunlight. This is 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 concentrating solar power plants.The modern age of solar power arrived in 1954 when researchers at Bell Laboratories developed a solar cell capable of effectively converting light into electricity. This breakthrough marked a fundamental change in how power is generated. Since then solar cells efficiencies have improved from 6% to 15% with experimental cells reaching efficiencies over 40%. Prices on the other hand have fallen from $300 per watt to less than $3 per watt.The utilization of solar energy spans from traditional technologies that provide food, heat and light to electricity which is uniquely modern. The diversity of form and long history of solar energy are manifest in a wide variety of applications. These include:
Heat (hot water, building heat, cooking, process heat)
