In little more than two decades, scientists and technologists have evolved a global, renewable-energy industry capitalizing on the free resources of wind and sun…
Global solar photovoltaic capacity has grown from around five gigawatts in 2005 to an approximately 306.5 gigawatts in 2016. This trend was accompanied by sharp drops in the price of photovoltaic panels. Global wind power also grew sharply from 4,117 MW in 2011 to 14,384 MW in 2016.
The first solar cells were developed in 1876 by William Adams and his student Richard Day, from their discovery that selenium, when exposed to light, produced electricity. The principle that light could be converted into electricity without heat or moving parts was recognized by the German industrialist, Werner von Siemens, as “scientifically of the most far-reaching importance.”
The groundwork for the modern solar power industry was laid in 1953 by Calvin Fuller, Gerald Pearson and Daryl Chapin who jointly invented the silicon solar cellwhich was sufficiently powerful to run small electrical gadgets. This discovery was reported by The New York Times as marking “the beginning of a new era, leading eventually to the realization of harnessing the almost limitless energy of the sun for the uses of civilization.”
During the space race between Russia and the U.S. solar cells with an efficiency of barely 14 percent were used to power space-crafts and satellites. In the 1970s a series of discoveries made by a team from the oil major Exxon, laid the foundations for dramatic cost reductions in solar cell production to around $20 per Watt today and efficiency improvements up to reach 44.5 percent in 2017.
Today there are utility-scale, grid-connected solar power stations. There is the solar thermal collector which uses thousands of parabolic mirrors to reflect the sun’s energy onto a focal point. The energy is used to heat water to produce steam which in turn powers a steam turbine to create electricity.