The Development of PV Systems

PV technology has been developing for more than 160 years and has progressed exponentially in the last couple decades allowing Photovoltaics to become a practical power generation technology. Edmund Becquerel, a French physicist was credited with the invention and discovery of the Photovoltaic effect in 1839. He observed an increase in electron emissions between a pair of electrodes submerged in an conductive solutions when the experiment was exposed to light.

In 1873, British engineer Willoughby Smith observed the high conductivity of selenium when exposed to light while testing underwater telegraph cables. This observation of photoconductivity led to the experimentations on how to use selenium to utilize solar energy.

The first true PV cells were developed by American inventor Charles Fritts in 1883. He covered a selenium wafer with transparent gold film, which produced a tiny current with a maximum efficiency never exceeding 1%. Though this was not practical since selenium is a rare element and production of cells was very expensive.

In 1954 Calvin Fuller and Gordon Pearson researchers at Bell Laboratories developed the first practical photovoltaic cell. They discovered that the use of silicon in transistors and rectifiers added enough impurities to produced an appreciable electric current when exposed to light. Subsequently this improved the modified silicon cell into the first useful PV cell with an efficiency of up to 6%.

Growth in PV development emerged during the space race in the 1950s and 1960s. In conjunction with the need for space technology due to the complexity of supplying power PV cells were ideal power generators for satellites and spacecraft from the abundant solar radiation outside Earths’ atmosphere. Vanguard I satellite in 1958 had the first cells developed and has been used on nearly every satellite and spacecraft since developed.

The First common Earth-based applications were in rural telephone systems and radio transmitters. But, it was not until Oil shortages in the 1970s increased interest in Earth-based PV applications to aid in energy crises. The U.S government initiated PV research and development projects which established the National Renewable Energy Laboratory (NREL).During this time significant advancements were made in PV technology, materials, inverters and interactive systems. Furthermore, federal legislation introduced tax credits to promote renewable energy production and financial incentive programs are available to consumers in the United States, Europe and Japan to encourage use of PV technology.