

160 Years of Photovoltaic Technology

Most people are surprised to learn that photovoltaic technology actually dates back over 160 years. The basic science was first discovered in 1839 but the pace of advancement really accelerated in three major thrusts in the 20th century. 1839 Experimenting with metal electrodes and electrolyte, nineteen-year-old French physicist Alexandre Edmond Becquerel observes a physical phenomenon allowing light-electricity conversion 1883 Charles Fritts, an American inventor, describes the first solar cells made from selenium wafers 1888 Edward Weston receives first US patent for "solar cell" 1901 Nikola Tesla receives US patent for "method of utilizing, and apparatus for the utlization of, radiant energy" Albert Einstein Makes His Mark It wasn't until Albert Einstein wrote his 1905 paper on the photoelectric effect: "On a Heuristic Viewpoint Concerning the Production and Transformation of Light". 1905 Albert Einstein publishes paper on theory behind “photoelectric effect” along with paper on relativity theory 1916 Robert Millikan provided experimental proof of Einstein’s theory on photoelectric effect 1922 Einstein wins Nobel prize for 1904 paper on photoelectric effect The Commercial Solar Age Begins Bell Laboratories, while working on silicon semiconductors, discovered silicon had photoelectric properties and quickly developed Si solar cells, achieving 6% efficiency and early satellites were the primary use for these first solar cells. 1954 Bell Labs exhibits first high-power silicon PV cell. The New York Times forcasts that solar cells will eventually lead to a source of "limitless energy of the sun". 1955 Western Electric sells commercial licenses for silicon PV technologies; early successful products include PV-powered dollar bill changers and devices that decoded computer punch cards and tape. 1958 PV array powers radios on US Vanguard I space satellite 1963 Sharp Corporation produces a viable photovoltaic module of silicon solar cells. Japan installs a 242-watt PV array on a lighthouse, the world's largest array at that time. 1966 NASA launches Orbiting Astronomical Observatory with a 1-kilowatt PV array 1970s Research drives PV costs down 80%, allowing for applications such as offshore navigation warning lights and horns lighthouses, railroad crossings, and remote use where utility-grid connections are too costly 1973 Solarex Corp is founded by two ex-NASA scientists who worked on the development of satellite PV systems 1974 Japan formulates “Project Sunshine” to fuel PV research and development 1976 Kyocera Corp begins production of Silicon ribbon crystal solar modules 1977 US Dept. of Energy establishes US Solar Energy Research Institute in Golden, CO 1980s Continued improvements in efficiency and cost enables PV to become a popular power source for consumer electronic devices, such as calculators, watches, radios, lanterns and other small battery charging applications Progressive Governments Use Subsidies to Speed Adoption To spur adoption, Germany and then Japan initiated considerable subsidy programs and now those markets exist largely without subsidies. In 2007, California leads the US with a similar 10-year program. 1990 Germany launches $500MM “100,000 Solar Roofs” program. The Cathedral of Magdeburg installs solar cells on the roof, marking the first installation on a church in East Germany 1991 President George H. W. Bush directs the U.S. Department of Energy to estalish the National Renewable Energy Laboratory (transerring the existing Solar Energy Research Institute) in Sandia, NM 1994 Japan begins "70,000 Solar Roofs" PV subsidy program 1998 California initiates $112MM “Emerging Renewables Program” to fund rebates for <30 kW residential and commercial PV systems

2002 CA Public Utilities Commission begins $100MM “Self Generation Incentive Program” for >30 kW PV projects 2004 Five manufacturers — Sharp, Kyocera, Shell Solar, BP Solar and RWE SCHOTT Solar — account for 60 percent of the PV market. GE buys Astropower, the last remaining US independent PV manufacturer 2006 The CA PUC demonstrates leadership by outlining what will become the California Solar Initiative (CSI), a 10-year, $3 billion solar subsidy program. 2007 The CSI program begins and is well received by the market, with higher than expected application volume. 2008 Your company joins the fast-growing list of California business leaders who adopt solar power for their business with Sunlight Electric.