Photovoltaics - Historical Development

The story of photovoltaics and how it all began in 1839, as a coincidence, just like many other discoveries in the past, such as penicillin, is very interesting reading. The story will take you through some facts, persons and events, which have marked the history of photovoltaics.

"Being desirous of obtaining a more suitable high resistance for use at the Shore Station in connection with my system of testing and signalling during the submersion of long submarine cables, I was induced to experiment with bars of selenium - a known metal of very high resistance. I obtained several bars, varying in length from 5 cm to 10 cm, and of a diameter from 1.0 mm to 1.5 mm. Each bar was hermetically sealed in a glass tube, and a platinum wire projected from each end for the purpose of connection..."

(Source: Willoughby Smith, Letter to Latimer Clark, Wharf Road, 4^th February 1873)^[1]

1839 - 1899
Discovery of Basic Phenomena and Propoerties of PV Materials

A physical phenomenon allowing light-electricity conversion - the photovoltaic effect, was discovered in 1839 by the French physicist, Alexandre Edmond Becquerel. Experimenting with metal electrodes and electrolyte he discovered that conductance rises with illumination. Willoughby Smith discovered the photovoltaic effect in selenium in 1873. In 1876, with his student Richard E. Day, William G. Adams discovered that illuminating a junction between selenium and platinum also has a photovoltaic effect. These two discoveries formed a foundation for the first selenium solar cell construction, which was built in 1877. Charles Fritts first described them in detail in 1883. In 1887, Heinrich Hertz discovered that ultraviolet light changes the voltage at which sparks between two metal electrodes would be initiated.

1900 - 1949
Theoretical Explanation of the Photovoltaic Effect and First Solar Cells

The author of the most comprehensive theoretical work about the photovoltaic effect was Albert Einstein, who described the phenomenon in 1904. For his theoretical explanation, he was awarded a Nobel Prize in 1921. Einstein's theoretical explanation was proven in practice by Robert Millikan's experiment in 1916. In 1918, a Polish scientist Jan Czochralski^[2] discovered a method for monocrystalline silicon production, which enabled monocrystalline solar cell production. The first silicon monocrystalline solar cell was constructed in 1941. In 1932, the photovoltaic effect in cadmium-selenide was observed. Nowadays, CdS is among the important materials for solar cell production.

1950 - 1969
Intensive Space Research

In 1951, the first germanium solar cells were made. Dan Trivich of Wayne State University made some theoretical calculations on solar cell efficiency with different materials, and on solar spectrum wavelengths in 1953. In 1954, the RCA Laboratories published a report on CdS photovoltaic effect. AT&T organised several demonstrations on solar cells functioning in the same year. Bell's Laboratories published the results of the solar cell operation with 4.5 % efficiency. The efficiency was increased to 6 % within a few months. In 1955, the preparation of satellite energy supply by solar cells began. Western Electric put up for sale commercial licenses for solar cell production. Hoffman Electronics-Semiconductor Division introduced a commercial photovoltaic product with 2 % efficiency for US$ 25 per cell with 14 mW peak power. The energy cost was US$ 1,785 per W. In 1957, Hoffman Electronics introduced a solar cell with 8 % efficiency. A year later, in 1958, the same company introduced a solar cell with 9 % efficiency. The first radiation-proof silicon solar cell was produced for the purposes of space technology in the same year. On 17^th March, the first satellite powered by solar cells, Vanguard I, was launched. The system ran continuously for 8 years. Two other satellites, Explorer III and Vanguard II, were launched by the Americans, and Sputnik III by the Russians. The first telephone repeater powered by solar cells was built in Americus, Georgia. In 1959, Hoffman Electronics introduced commercially available solar cells with 10 % efficiency. The Americans launched the satellites, Explorer VI, with photovoltaic field of 9,600 cells and Explorer VII. In 1960, Hoffman Electronics introduced yet another solar cell with 14 % efficiency. The first sun-powered automobile was demonstrated in Chicago, Illinois on August 31^st 1955. A United Nations conference on solar energy application in developing countries took place in 1961. The Defence Studies Institute organised the first photovoltaic conference during the same year, in Washington. In 1962, the first commercial telecommunications satellite, Telstar, developed by Bell Laboratories, was launched. The photovoltaic system peak power for satellite power supply was 14 W. The second photovoltaic conference took place in Washington. In 1963, Sharp Corporation developed the first usable photovoltaic module from silicon solar cells. The biggest photovoltaic system at the time, the 242 W module field, was set up in Japan. A year later, in 1964, Americans applied a 470 W photovoltaic field in the Nimbus space project. In 1965, the Japanese scientific programme for Japanese satellite launch commenced. The following year, in 1966, an astronomical observatory with 1 kW peak power photovoltaic module field was tracked in the earthly orbit. In 1968, the OVI-13 satellite with two CdS panels was launched. In 1969, Roger Little established Spire Corporation, which became and still is an important producer of solar cells production equipment.

1970 - 1979
Establishment of Large Photovoltaic Companies

In 1972, Solar Power Corporation was established. The company started commercial business in 1973, when a sales office in Braintree, Massachusetts was opened^[3]. The French implemented a CdS photovoltaic system, enabling an educational TV programme broadcast in the province of Niger in 1972. A year later, in 1973, Solarex Corporation was established. At Delaware University a photovoltaic-thermal hybrid system, Solar one, one of the first photovoltaic systems for domestic application, was developed. Besides the photovoltaic system, the system also incorporated also a warmth keeper of phase-changeable materials. A silicon solar cell of US$ 30 per W was produced. In 1974, the Japanese Sunshine project commenced. A year later, in 1975, Solec International and Solar Technology International were established. The American government encouraged JPL Laboratories to conduct research in the field of photovoltaic systems for application on Earth the same year. In 1976, under NASA protection, Lewis Research Center (LeRC) commenced photovoltaic system installations for application on Earth, which continued until 1985 and later, from 1992 until 1995. The systems were meant for refrigerators, telecommunication equipment, medical equipment, lighting and water pumping power supply, as well as for other applications. NASA LeRC introduced several demonstration projects. The first amorphous silicon solar cell was developed by RCA Laboratories the same year. In 1977, the world production of photovoltaic modules exceeded 500 kW. NASA LeRC commenced implementing photovoltaic systems in six meteorological stations in different locations within USA. NASA LeRC introduced additional trial demonstration projects. Solar Energy Research Institute, located in Golden, Colorado launched its operation. In an American Indian reservation, NASA LeRC set up a 3.5 kW system - the first system ever to satisfy the demands of the entire village. It was used for water pumping and power supply of 15 households. In 1979, ARCO Solar of Camarillo, California, built the biggest solar cell and photovoltaic systems production plant premises at that time. NASA LeRC built a 1.8 kW water pumping photovoltaic system in Burkina Faso. The system peak power was enlarged to 3.6 kW the same year. In Mt. Laguna, California, a trial 60 kW hybrid diesel-photovoltaic system was built for radar station power supply.

1980 - 1989
First Large Utility-Scale Photovoltaic Systems

Many important events in the field of photovoltaics appeared in 1980. ARCO Solar was the first to produce photovoltaic modules with peak power of over 1 MW per year. A trial photovoltaic system installation was built in the centre of the volcano observatory in Hawaii. A new company, BP, appeared in the market. On behalf of Ford, Bacon & Davis, Utah, Wasatch Electric built a 105.6 kW system in the State of Utah. The modules integrated into the system were produced by Motorola, ARCO Solar and Spectrolab. The facility is still operating^[4] and is being maintained by a National Park Service contractor and supplies power to the headquarters of Natural Bridges National Monument in Southern Utah. A year later, in 1981, NASA LeRC began to build systems for vaccine refrigerator power supply at 30 locations around the globe (the project was closed in 1984). Solar Challenger, the first plane ever powered by solar energy, took off. A system with peak power of 90.4 kW, with modules produced by Solar Power Corporation, was built in Square Shopping Center in Lovington, New Mexico. A similar system was built for Beverly High School in Beverly, Massachusetts. A seawater desalination system with 10.8 kW peak power was built in Jeddah, Saudi Arabia the same year. Helios Technology, the oldest European solar cells producer, was established. The world production of photovoltaic modules exceeded 9.3 MW in 1982. Solarex established Solarex Aerospace division the same year. At the Vienna conference, NASA LeRC introduced a trial case of a terrestrial satellite reception station and public lighting electricity supply. Volkswagen began testing photovoltaic systems placed on vehicle roofs with 160 W peak power for vehicle start-up. Solarex production premises rooftops in Frederick, Maryland, were equipped with photovoltaic systems with 200 kW peak power. ARCO Solar built a 1 MW PV power plant with modules on over 108 double-axis trackers in Hesperia, California.

Solar cars

A year later, in 1983, the worldwide production of photovoltaic modules exceeded 21.3 MW peak power, with product value of US$ 250 million. A Solar Trek vehicle with a 1 kW photovoltaic system drove 4,000 km in the twenty days of the Australia Race. The maximum speed was 72 km/h and the average speed was 24 km/h. The same year, the vehicle surpassed the distance of 4,000 km between Long Beach, California, and Daytona Beach, Florida, in 18 days. Solarex Corporation bought amorphous cells production technology from cells producer RCA and built its own trial power plant in Newtown, Pennsylvania. ARCO Solar built a 6 MW photovoltaic power plant as a subsystem of the public electricity grid for a Pacific Gas and Electric Company application in California. The system satisfied the demand of 2,000 to 2,500 households. Solar Power Corporation built four standalone photovoltaic systems for the needs of a village in Tunisia with total peak power of 31 kW per system. A 1.8 kW photovoltaic system was built to satisfy the needs of the local hospital in Guyana. The applications, such as vaccine refrigerators, indoor lighting, ordination lighting and radio appliances, were powered by the system. The system was planned and built by NASA LeRC and Solarex. A similar, yet more powerful, photovoltaic system of 4 kW was set up in Ecuador. A 1.8 kW photovoltaic system was set up in Zimbabwe for the same purpose. Solarex Corporation merged with Amoco Solar Company, owned by Standard Oil Company.

The first amorphous solar module

In 1984, a 1 MW photovoltaic power plant began to operate in Sacramento, California. ARCO Solar introduced the first amorphous modules. NASA LeRC placed seventeen photovoltaic systems to satisfy the demands of the local schools, lighting, medical equipment and water pumping in Gabon. BP Solar Systems, with EGS donations, built a 30 kW photovoltaic system connected to public electric grid nearby Southampton, Great Britain. Solarex Corporation closed the equipment supply for a photovoltaic system for Georgetown University Intercultural Center demands, with total peak power of 337 kW and 4,464 modules. BP Solar bought Monosolar thin-film division, Nortek, Inc.

Highly efficient silicon solar cells and thin-film solar module

In 1985, researchers at the University of New South Wales in Australia constructed a solar cell with more than 20 % efficiency. BP built a power plant in Sydney, Australia and shortly afterwards, another one nearby Madrid. A photovoltaic system was built in Sulawesi, Indonesia for the purposes of a terrestrial satellite station. In 1986, ARCO Solar introduced a G-4000, the first commercial thin film photovoltaic module.

Solar car races - a new challenge for research labs

In the Pentax World Solar Challenge 1987 race through Australia, a General Motors Sunracer vehicle won with an average speed of 71 km/h. In 1988, the fourth Tour de Sol race of 350 km in Switzerland and Austria took place. The vehicle categories included photovoltaic supplied vehicles, additional pedal vehicles, commercial photovoltaic supplied vehicles and electric vehicles without photovoltaic supply. The overall award fund was worth SFR 140,000.

Third World projects and new production capacities

Solarex received the United Nations tender to supply a 50 kW system for UN research project requirements in Pakistan. ARCO Solar increased the thin film system production capacities in Camarillo, California to 7 MW per year. ARCO Solar opened production in Japan and Germany. BP Solar received a thin film technology patent for solar cells production in 1989.

1990 - 1999
Large-Scale Solar Cell Producers

In 1990, Energy Conversion Devices Inc. (ECD) and Canon Inc. established a joint company, United Solar Systems Corporation, for solar cell production. Siemens bought ARCO Solar and established Siemens Solar Industries. Solar Energy Research Institute (SERI) was renamed to National Renewable Energy Laboratory (NREL). A year later, in 1991, BP Solar Systems was renamed to become BP Solar International (BPSI) and became an independent unit within the British Petroleum Group. In 1992, a photovoltaic system of 0.5 kW was placed in Antarctica for the laboratory, lighting, personal computers and microwave oven power requirements. A silicon solar cell with 20 % efficiency was patented. In 1994, the National Renewable Energy Laboratory (NREL), an important institution in the field of renewable energy sources in USA, launched its website on the Internet. DOE built several trial systems for the needs of agriculture, hospitals, lighting, water pumping, etc. in Brazil. ASE GmbH, from Germany, purchased Mobil Solar Energy Corporation technology and established ASE Americas, Inc. A year later, in 1995, the first international fund for the promotion of photovoltaic system commercialisation was established, which supported projects in India. The World Bank and the Indian Renewable Energy Sources Agency sponsored projects in co-operation with Siemens Solar. In 1996, BP Solar purchased APS production premises in California, and announced a commercial CIS solar cells production. Icar, the plane powered by solar energy, with 3,000 solar cells in total on its surface of 21 m² flew over Germany. Activities, which will result in 36,400 50 W systems within the next three years, started in Indonesia. In 1999, Solar Cells, Inc. (SCI), True North Partners, and LLC of Phoenix, Arizona merged to become First Solar, LLC.

2000 - 2009
Multi MW Utility-Scale PV Power Plants

Mostly in Germany, some photovoltaic and renewable energy resources companies have shares listed on the stock exchange. Capital mergers in Germany led to the establishment of large photovoltaic corporations. During 2000 and 2001 production of Japanese manufacturers increased significantly. Sharp and Kyocera each produce modules with peak power equivalent to the annual consumption in Germany, the most demanding European market. Sanyo is close as well. After many years of research and trial flights, the HELIOS solar powered plane, developed by NASA and AeroVironment Inc., broke the height record on 13^th August 2001. HELIOS reached a height of almost 30,000 meters. During the 2002 - 2003 period, several large power plants were built in Germany. On April 29^th 2003 the world's largest photovoltaic plant at that time was connected to the public grid in Hemau near Regensburg (Bavaria), Germany. The peak power of the "Solarpark Hemau" plant is 4 MW. Due to the “EEC” renewable energy law  many other large systems of up to 5 MW were built in Germany in the year 2004. Some of them are Geiseltalsee, Leipzig, Bürstadt, Göttelborn solar parks and others.

Notes

Books

	Butti, Ken and John Perlin. 1980. Golden Thread:Twentyfive Hundred Years of Solar Architecture and Technology. Palo Alto, CA: Cheshire Books. ISBN 978-0917352089.
	Janzing, Bernward. 2011. Solare Zeiten, Die Karriere der Sonnenenergie, Eine Geschichte von Menschen mit Visionen und Fortschritten der Technik. Freiburg: Picea Verlag. ISBN 978-3-981426502.
	Palz, Wolfgang (ed.). 2010. Power for the World: The Emergence of Electricity from the Sun. Singapore: Pan Stanford Publishing. ISBN 978-981-430-337-8.
	Palz, Wolfgang (ed.). 2013. Solar Power for the World: What You Wanted to Know about Photovoltaics. Singapore: Pan Stanford Publishing. ISBN 978-981-441-187-5.
	Perlin, John. 1999. From Space to Earth: Ann Arbor, MI: Aatec Publications, 1999, ISBN 0-674-01013-2.
	Perlin, John. 2013. Let it Shine: The 6,000-Year Story of Solar Energy. Novato, CA: New World Library. ISBN 978-1-60868-132-7.
	Pope, Charles H. 1906. Solar Heat, It's Practical Applications, second edition. Boston, MA: Charles Pope.
	Rau, Hans. 1976. Heliotechnik, 3. Auflage. München: Udo Pfriemer Verlag. ISBN 3-7906-0061-X.
	Varadi, Peter F. 2011. Terrestrial Photovoltaic Industry - The Beginning. In: Wolfgang, Palz (ed.), Power for the World, The Emergence of Electricity from the Sun, pp.555–567. Singapore: Pan Stanford Publishing. ISBN 978-981-430-337-8.
	Varadi, Peter F. 2014. Sun Above the Horizon: Meteoric Rise of the Solar Industry. Singapore: Pan Stanford Publishing. ISBN 978-9814463805.

Papers

	Gay, Charles F. and Chris Eberspacher. 1994. Worldwide photovoltaic market growth 1985-2000. In: Progress in Photovoltaics, Volume 2, Issue 3, pp.249–255. DOI 10.1002/pip.4670020309.
	Green, Martin. 2005. Silicon photovoltaic modules a brief history of the first 50 years. In: Progress in Photovoltaics, Volume 13, Issue 5, pp.447–455. DOI 10.1002/pip.612.
	Green, Martin A. 2009. The path to 25 % silicon solar cell efficiency: History of silicon cell evolution. In: Progress in Photovoltaics: Research and Applications, Volume 17, Issue 3, pp.183–189. DOI 10.1002/pip.892.
	Loferski, Joseph L. 1993. The first fourty years: A brief history of the modern photovoltaic age. In: Progress in Photovoltaics, Volume 1, Issue 1, pp.67–78. DOI 10.1002/pip.4670010109.
	Smith, Willoughby. 1873. Effect of Light on Selenium During the Passage of An Electric Current. In: Nature, Volume 7, p.303. DOI 10.1038/007303e0.

Links

	US Department of Energy, Solar Timeline.
	IEEE Global History Network, Rusell Ohl.