History of Solar Energy
Humans first harnessed the power of the sun as far back as the 7th century BC, by using magnifying glasses to intensify the sun's heat to make fire. The Romans and Greeks later achieved the same result with the use of concentrating mirrors.
In the 18th century Swiss geologist Horace de Saussure constructed what could be considered the world's first solar cookers. His 'heat traps' consisted of a series of glass boxes, a bit like small greenhouses increasing in size, stacked one over another. When as many as five boxes were stacked together and exposed to solar radiation, the temperature inside the innermost one would rise as high as 108 degrees Celsius – hot enough to boil water and cook food.
In 1839, at just 19 years old, the scientist Edmond Becquerel discovered the photovoltaic effect – the generation of voltage or current in a material when exposed to light. He first observed this effect in an electrolytic cell made out of two platinum electrodes partially submerged in an electrolyte (a solution that conducts electricity). He observed that when light was shone on the acidic silver chloride solution, the cell's current increased.
French physicist Augustin Mouchot was surprisingly ahead of his time when, in the 1860s and 1870s, he started developing solar-powered steam engines to address the issue of coal being a limited resource. He came up with the first parabolic trough solar collector, but the idea didn't take off. As the price of coal dropped, solar technology became more expensive in comparison and the French government cut their funding for Mouchot's research.
Meanwhile in Britain, in 1876 William Grylls Adams and Richard Evans Day demonstrated a photovoltaic effect from a junction based on platinum and the semiconductor selenium. The device performed poorly, but seven years later Charles Fritts created a new PV device based on a gold-selenium junction which delivered a light-to-electricity conversion efficiency of 1%.
In 1887 Heinrich Hertz observed the photoelectric effect, noting that some charged objects lost their charge more quickly when ultraviolet light was shone on them.
Albert Einstein then published a paper in 1905 which explained the photoelectric effect as a result of light energy being carried within individual quantized packets (photons). He went on to receive the Nobel Prize for this paper in 1921.
In 1918 Jan Czochralski, a Polish scientist, made a significant contribution to solar technology by discovering a way to grow single-crystal silicon based on c-Si wafers. This technique was refined and built upon in the later part of the 20th century.
In 1932 the photovoltaic effect was identified in cadmium sulfide, a II-VI semiconductor material, by Audobert and Stora. It wasn't until 1953 that a method was found for estimating the potential performance of solar cells made from various materials with various band gaps. Dr. Dan Trivich of Wayne State University performed these theoretical calculations with reference to the solar spectrum.
The development of photovoltaic devices to the standards we recognise today really took off at Bell Labs in America. In 1954 Bell Telephone Laboratories achieved 4% light-to-electricity conversion efficiency from a silicon solar cell, and they later increased this to 11%. In the mid-to-late fifties other companies and labs in the US, including Signal Corps Laboratories, RCA Lab and Hoffman Electronics, produced silicon-based solar cells that could be used to power satellites orbiting the Earth. Into the next decade, space exploration drove the demand for more efficient PV technology. Among the satellites in the Vanguard, Explorer and Sputnik series were some that used PV-powered systems.
Space technology and solar power continued to develop concurrently, with Bell Telephone Laboratories launching the first solar-powered telecommunications satellite in 1962 and NASA's first Orbiting Astronomical Observatory following in 1966 powered by a 1 kW photovoltaic solar array.
Over in Italy, in 1968 Professor Giovanni Francia constructed the first concentrated solar power plant near Genoa. It had the capability to produce 1 MW with superheated steam at 100 bar and 500 degrees Celsius. Note that these pictures are simply representative of the technology used and do not show the plant itself.
A couple of years later, in 1970 in the USSR, Zhores Alferov developed a high-efficiency solar cell based on gallium arsenide heterojunction solar cells. This was the first time a solar cell had been successfully based on III-V semiconductor materials.
In 1976, Dave Carlson and Chris Wronski of RCA Laboratories developed the first thin-film photovoltaic devices from amorphous silicon (a-Si), leading to SHARP and Tokyo Electronic Applications Laboratory releasing the first solar-powered calculators to the market in Japan in 1978.
As a result of the oil crisis and subsequent rises in oil prices during the seventies, public interest in photovoltaic technology grew. It was no longer only useful in space; there was demand for it down on the ground as well. The number of companies developing PV modules and systems for terrestrial applications increased substantially during the late seventies and into the eighties.
With this increased competition came advances in efficiency. In 1980 at the University of Delaware, thin-film solar cells made from copper sulfide or cadmium sulfide showed conversion efficiencies above 10%. This had advanced to above 20% by 1985, with the use of crystalline silicon (c-Si) solar cells at the University of New South Wales in Australia.
Between 1984 and 1991 construction took place on the largest solar thermal energy generating facility in the world. The facility in the Mojave Desert in California consisted of nine solar plants with a combined capacity of 354 MW.
In 1991 Michael Grëtzel and co-workers at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland published work on the first high-efficiency dye-sensitized solar cell. This technology operated on a kind of photoelectrochemical system whereby a semiconductor material based on molecular sensitizers is positioned between a photoanode and an electrolyte.
In 1994, the 30% conversion limit was exceeded by concentrator solar cells containing III-V semiconductor material developed by National Renewable Energy Laboratory (NREL) in the US.
All of these efforts combined meant that by the end of the 20th century, total worldwide installed photovoltaic power had reached 1 GW.
As the new millennium began, the demand for solar power was driven further by a public interest in environmental and economic issues. The solar market began the transformation from a local market into a global one. Germany was one of the forward-thinkers at this point, introducing a progressive feed-in tariffs policy which resulted in a strong national solar industry.
Germany remained market leaders for most of the decade; in 2010, 43% of the world's PV systems were installed in Germany. But China had caught on and its government had invested heavily in solar technology, meaning that just a few years later Chinese manufacturers were dominating the PV module market.
In 2012 the worldwide solar energy capacity exceeded the 100 GW mark, meaning it had increased one hundredfold in just in just 13 years. This equated to annual growth of 40% each year for that period.
With growth continuing this rapidly, there is every chance that solar energy will soon become the largest non-fossil fuel energy source worldwide.
## General information for non-commercial purpose from: University of Delft, DelftX: ET.3034TU Solar Energy
In the 18th century Swiss geologist Horace de Saussure constructed what could be considered the world's first solar cookers. His 'heat traps' consisted of a series of glass boxes, a bit like small greenhouses increasing in size, stacked one over another. When as many as five boxes were stacked together and exposed to solar radiation, the temperature inside the innermost one would rise as high as 108 degrees Celsius – hot enough to boil water and cook food.
In 1839, at just 19 years old, the scientist Edmond Becquerel discovered the photovoltaic effect – the generation of voltage or current in a material when exposed to light. He first observed this effect in an electrolytic cell made out of two platinum electrodes partially submerged in an electrolyte (a solution that conducts electricity). He observed that when light was shone on the acidic silver chloride solution, the cell's current increased.
French physicist Augustin Mouchot was surprisingly ahead of his time when, in the 1860s and 1870s, he started developing solar-powered steam engines to address the issue of coal being a limited resource. He came up with the first parabolic trough solar collector, but the idea didn't take off. As the price of coal dropped, solar technology became more expensive in comparison and the French government cut their funding for Mouchot's research.
Meanwhile in Britain, in 1876 William Grylls Adams and Richard Evans Day demonstrated a photovoltaic effect from a junction based on platinum and the semiconductor selenium. The device performed poorly, but seven years later Charles Fritts created a new PV device based on a gold-selenium junction which delivered a light-to-electricity conversion efficiency of 1%.
In 1887 Heinrich Hertz observed the photoelectric effect, noting that some charged objects lost their charge more quickly when ultraviolet light was shone on them.
Albert Einstein then published a paper in 1905 which explained the photoelectric effect as a result of light energy being carried within individual quantized packets (photons). He went on to receive the Nobel Prize for this paper in 1921.
In 1918 Jan Czochralski, a Polish scientist, made a significant contribution to solar technology by discovering a way to grow single-crystal silicon based on c-Si wafers. This technique was refined and built upon in the later part of the 20th century.
In 1932 the photovoltaic effect was identified in cadmium sulfide, a II-VI semiconductor material, by Audobert and Stora. It wasn't until 1953 that a method was found for estimating the potential performance of solar cells made from various materials with various band gaps. Dr. Dan Trivich of Wayne State University performed these theoretical calculations with reference to the solar spectrum.
The development of photovoltaic devices to the standards we recognise today really took off at Bell Labs in America. In 1954 Bell Telephone Laboratories achieved 4% light-to-electricity conversion efficiency from a silicon solar cell, and they later increased this to 11%. In the mid-to-late fifties other companies and labs in the US, including Signal Corps Laboratories, RCA Lab and Hoffman Electronics, produced silicon-based solar cells that could be used to power satellites orbiting the Earth. Into the next decade, space exploration drove the demand for more efficient PV technology. Among the satellites in the Vanguard, Explorer and Sputnik series were some that used PV-powered systems.
Space technology and solar power continued to develop concurrently, with Bell Telephone Laboratories launching the first solar-powered telecommunications satellite in 1962 and NASA's first Orbiting Astronomical Observatory following in 1966 powered by a 1 kW photovoltaic solar array.
Over in Italy, in 1968 Professor Giovanni Francia constructed the first concentrated solar power plant near Genoa. It had the capability to produce 1 MW with superheated steam at 100 bar and 500 degrees Celsius. Note that these pictures are simply representative of the technology used and do not show the plant itself.
A couple of years later, in 1970 in the USSR, Zhores Alferov developed a high-efficiency solar cell based on gallium arsenide heterojunction solar cells. This was the first time a solar cell had been successfully based on III-V semiconductor materials.
In 1976, Dave Carlson and Chris Wronski of RCA Laboratories developed the first thin-film photovoltaic devices from amorphous silicon (a-Si), leading to SHARP and Tokyo Electronic Applications Laboratory releasing the first solar-powered calculators to the market in Japan in 1978.
As a result of the oil crisis and subsequent rises in oil prices during the seventies, public interest in photovoltaic technology grew. It was no longer only useful in space; there was demand for it down on the ground as well. The number of companies developing PV modules and systems for terrestrial applications increased substantially during the late seventies and into the eighties.
With this increased competition came advances in efficiency. In 1980 at the University of Delaware, thin-film solar cells made from copper sulfide or cadmium sulfide showed conversion efficiencies above 10%. This had advanced to above 20% by 1985, with the use of crystalline silicon (c-Si) solar cells at the University of New South Wales in Australia.
Between 1984 and 1991 construction took place on the largest solar thermal energy generating facility in the world. The facility in the Mojave Desert in California consisted of nine solar plants with a combined capacity of 354 MW.
In 1991 Michael Grëtzel and co-workers at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland published work on the first high-efficiency dye-sensitized solar cell. This technology operated on a kind of photoelectrochemical system whereby a semiconductor material based on molecular sensitizers is positioned between a photoanode and an electrolyte.
In 1994, the 30% conversion limit was exceeded by concentrator solar cells containing III-V semiconductor material developed by National Renewable Energy Laboratory (NREL) in the US.
All of these efforts combined meant that by the end of the 20th century, total worldwide installed photovoltaic power had reached 1 GW.
As the new millennium began, the demand for solar power was driven further by a public interest in environmental and economic issues. The solar market began the transformation from a local market into a global one. Germany was one of the forward-thinkers at this point, introducing a progressive feed-in tariffs policy which resulted in a strong national solar industry.
Germany remained market leaders for most of the decade; in 2010, 43% of the world's PV systems were installed in Germany. But China had caught on and its government had invested heavily in solar technology, meaning that just a few years later Chinese manufacturers were dominating the PV module market.
In 2012 the worldwide solar energy capacity exceeded the 100 GW mark, meaning it had increased one hundredfold in just in just 13 years. This equated to annual growth of 40% each year for that period.
With growth continuing this rapidly, there is every chance that solar energy will soon become the largest non-fossil fuel energy source worldwide.
## General information for non-commercial purpose from: University of Delft, DelftX: ET.3034TU Solar Energy
