Over the course of man’s history, solar power has played an essential part. The sun’s rays have provided power in more forms than just electricity or the creation of steam: light, comfort, inspiration, an early method of time-telling and even our earliest reasons for looking for a higher power are all a direct result of solar power. So what is the history of our earliest and greenest form of energy?
Pre- And Early History
The earliest that scientists estimate that man realised the sun’s ability to create and rustic forms of power predates homo sapiens. Man’s early ancestors are thought to have realised that patches of sunlight on the ground were much warmer than those in the shade and that rocks heated by the sun during the day retained it at night. With this knowledge, solar powered heating was born, with man choosing and building homes that sat in sunlight during the day. The Romans and Egyptians continued this by building homes with south-facing windows – a practice modern man still upholds.
But what about using solar power to literally power things? These advances wouldn’t come until 1767 when Horace-Benedict de Saussure invented a device that is considered by most to be the world’s first solar collector. Little more than an insulated box with an opening covered by three layers of glass, the device could reach internal temperatures of 230 degrees Fahrenheit and would form a basis for future discoveries in solar.
Converting sunlight into electricity would take a further 72 years, when scientist Edmond Becquerel exposed two electrodes within an electrolyte to the sun’s rays, observing an increase in electrical current – a process we now understand as the photovoltaic effect, the very science on which the PV cells of solar panels are constructed. Becquerel did not understand the physics of this process and it would be 1905, when Albert Einstein published an explanation of the photoelectric effect, before the wider scientific community also understood it.
After Becquerel’s discovery entered French inventor Augstin Mouchot, who had serious doubts about the long term sustainability of coal in 1860. He began building upon Saussure’s “oven”, creating a water-filled container within a glass envelope that would generate heat, causing the water to boil when left in the sun. With this rudimentary solar powered device, Mouchot was able to power a small steam engine and so solar power was truly born. At the time the French government supported Mouchot’s discovery, even going as far as to offer funding, but when the price of coal dropped so did France’s support for solar power and work on Mouchot’s solar powered solution stopped.
The Birth Of the Solar Cell
Further advances to the technology would finally arrive in 1873, when Willoughby Smith discovered the selenium was a photoconductive material and then again three years later when William Grylls Adams and Richard Evans Day were able to demonstrate that solid material with no moving parts could successfully convert sunlight directly into electricity.
After this, a basic solar cell followed in 1886 when American inventor Charles Fritts created some from selenium wafers. These cells were not terribly effective and it wouldn’t be until 1954 that what we recognise as a true solar photovoltaic cell would be created by Bell Laboratories. A few years later this technology would become commercially available and NASA would use it in its early space race attempts.
Perfecting The Technology
Still, solar energy was not seen as cost-effective and so wasn’t adopted by private citizens. In the early 70s, the oil embargo in the US pushed governments to explore alternative fuels and thanks to work from Dr. Elliot Berman and the University of Delaware, the production price of solar energy dropped from $100 per watt to just $20 and a new, cheaper solar cell was invented simultaneously, allowing the general public to start going solar for the first time.
The science behind solar power is changing all the time, with the cells becoming cheaper and more efficient with every passing day. Just this year solar cells ten times thinner, lighter and more flexible have been created by Researchers from University of Tokyo and IBM have created a new cell with record-breaking efficiency.
Solar power has taken hundreds of years to get to where it is now, but the only thing that looks to be able to stop this energy giant is a Red Giant!
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This is a guest post. Jessica writes about solar energy for the Solar Contact website where you can learn more about solar power and solar panel technology.