The Renewable Energy seminar has increased my preparation for courses and curricular areas I am assigned to teach in Mathematics and Physics, relative to the effectiveness and efficiency of renewable energies. Solar energy has been harnessed from the radiant light and heat of the Sun since the ancient times of human development, using a broad range of ever-evolving technologies. The recorded history of solar power and solar technology had a surprising start in the 7
Century B.C. when glass and mirrors were first focused to concentrate heat from the Sun and light fires. Subsequently, the contemporary powering of buildings and vehicles from solar energy has resulted from a robust history of discovery, experimentation, and implementation. Clearly, a more comprehensive glimpse onto the future is achieved by realizing notable accomplishments in the historical development of solar technology, throughout time and recorded history.
As early as the 7th Century B.C., the magnifying glass had been used to concentrate the sunlight to make fire, similar to the Greeks and Romans who used mirrors to light torches for religious ceremonies in the 3rd Century B.C.. In the year 212 BC, and the 3rd Century B.C., the Greek scientist, Archimedes, used the reflective properties of bronze shields to focus sunlight on and to set fire to wooden ships from the Roman Empire during the Siege of Syracuse. Later, to demonstrate the validity of this claim, the Greek navy re-enacted this feat as an experiment in 1973 and successfully set fire to a wooden boat at a distance of 50 meters. The Chinese were also successful in lighting torches for religious ceremonies as recorded in 20 A.D..
The famous Roman bathhouses in the first to fourth centuries A.D. had large south facing windows to let in the Sun's warmth, as discovered by the Hebrew University of Jerusalem at the Zippori Park archeological sites from the Roman Period, 1st to 4th Century A.D.. During the 6th Century A.D., sunrooms on houses and public buildings were so common that the Justinian Code initiated "Sun Rights" to ensure individual access to the Sun. Similarly, the ancestors of Pueblo people, called Anasazi in North America, lived in south-facing cliff dwellings that capture the winter Sun during the 1200s A.D.. Hot Boxes of the 1700s were credited to Swiss scientist Horace de Saussure in 1767 for the world's first solar collector on which Sir John Herschel later cook food during his South African expedition in the 1830s.
On September 27, 1816, Robert Stirling, a minister in the Church of Scotland, applied for a patent at the Chancery in Edinburgh, Scotland for heat engines that he had fabricated. Lord Kelvin used one of the working models during some of his university classes. This engine was later used in the dish/Stirling system, a solar thermal electric technology that concentrates the Sun's thermal energy in order to produce power. Subsequently, the French scientist Edmond Becquerel discovered a photovoltaic effect in 1839, while experimenting with an electrolytic cell made up of two metal electrodes placed in an electricity-conducting solution and that the electricity-generation increased when exposed to light.
The French mathematician August Mouchet developed a concept for solar-powered steam engines in 1860,. In the following two decades, he and his assistant, Abel Pifre, constructed the first solar powered engines for a variety of applications, and they were the predecessors of modern parabolic dish collectors. Willoughby Smith discovered the photoconductivity of selenium in 1873 and in 1876 William Grylls Adams and Richard Evans Day discovered that selenium produces electricity when exposed to light. Although selenium solar cells failed to convert enough sunlight to power electrical equipment, they proved that a solid material could change light into electricity without heat or moving parts.
Samuel P. Langley invented the bolometer in 1880, which was used to measure light from the faintest stars and the heat from that sunlight with a fine wire connected to an electric circuit. When radiation fell on the wire, it became warmer and increased the electrical resistance of the wire. In 1883, Charles Fritts, an American inventor, described the first solar cells made from selenium wafers. Heinrich Hertz discovered that ultraviolet light altered the lowest voltage capable of causing a spark to jump between two metal electrodes. In Baltimore, inventor Clarence Kemp patented the first commercial solar water heater in 1891 at The California Solar Center.]3]
Wilhelm Hallwachs discovered that combinations of copper and cuprous oxide are photosensitive in 1904, while Albert Einstein published his paper on the photoelectric effect in 1905, with a paper on his famous theory of relativity. William J. Bailley of the Carnegie Steel Company develops a solar collector with copper coils and an insulated box in 1908, and very similar to the current design, and by 1914 the importance of barrier layers in photovoltaic devices was recognized. By 1916, Robert Millikan provided experimental proof of that photoelectric effect and Polish scientist Jan Czochralski developed a way to grow single-crystal silicon.  Albert Einstein won the Nobel Prize in 1921 for his theories that explain the photoelectric effect as published in his 1904research and technical paper. The photovoltaic effect in cadmium sulfide (CdS) was discovered in 1932 by Audobert and Stora.
By 1947, the popularity of passive solar architecture in the United States rose as a result of scarce energy during the prolonged WW2, that Libbey-Owens-Ford Glass Company published a book entitled Your Solar House that profiled forty-nine of the nation's greatest solar architects. Dr. Dan Trivich, Wayne State University, makes the first theoretical calculations of the efficiencies of various materials of different band gap widths based on the spectrum of the Sun in 1953. The following year, 1954, marked the beginning of photovoltaic technology in the United States when Daryl Chapin, Calvin Fuller, and Gerald Pearson develop the silicon photovoltaic (PV) cell at Bell Labs as the first solar cell capable of converting enough solar energy to power everyday electrical equipment.
Bell Telephone Laboratories produced a silicon solar cell with 4% efficiency and later achieved 11% efficiency. Then in 1955, Western Electric sold commercial licenses for silicon photovoltaic (PV) technologies. Early successful products included PV-powered dollar bill changers and devices that decoded computer punch cards and tape. In 1955, architect Frank Bridgers designed the world's first commercial office building using solar water heating and passive design, the Bridgers-Paxton Building, which has been continuously operating since that time and is now in the National Historic Register as the world's first solar heated office building. William Cherry, U.S. Signal Corps Laboratories, approached RCA Labs' Paul Rappaport and Joseph Loferski in 1956 about developing photovoltaic cells for the proposed orbiting Earth satellites.
Hoffman Electronics achieved 8 percent efficiency from one version of photovoltaic cells in 1957, and 9 percent efficiency from an improved version of photovoltaic cells in 1958. Also in1958, T. Mandelkorn, U.S. Signal Corps Laboratories, fabricated n-on-p silicon photovoltaic cells, which would prove to be critically important for space cells because of a greater resistance to radiation. During that same year, 1958, the Vanguard I space satellite used a small array of photovoltaic cells of less than one watt for radio power. Later that year, Explorer III, Vanguard II, and Sputnik-3 were launched with PV-powered systems on board. Despite unsuccessful attempts to commercialize the silicon solar cell in the 1950s and 19660s, powering satellites was always successful. Solar power became the accepted energy source for space applications. Then in 1959, Hoffman Electronics achieved 10 percent efficiency from commercially available photovoltaic cells and added grid contacts to reduce the series resistance significantly.
On August 7, 1959, the Explorer VI satellite was launched with a photovoltaic array of 9600 cells, measuring 1 cm x 2 cm each, followed by the Explorer VII satellite launching on October 13, 1959. By 1960, Hoffman Electronics achieved 14 percent efficiency with photovoltaic cells and Silicon Sensors, Inc., of Dodgeville, Wisconsin, was founded and started producing selenium and silicon photovoltaic cells. Bell Telephone Laboratories launched the first telecommunications satellite in 1962 called the Telstar and initially powered by 14 watts derived from a P-V system. The Sharp Corporation succeeds in producing practical silicon photovoltaic modules in 1963 and Japan installs a 242-watt, photovoltaic array on a lighthouse, and the world's largest array at that time. NASA launches the first Nimbus spacecraft in 1964, which was a satellite powered by a 470-watt photovoltaic array.
Peter Glaser conceives the idea of the satellite solar power station in the DOE's reference brief "Solar Power Satellites."  NASA launches the first Orbiting Astronomical Observatory in 1966, powered by a 1-kilowatt photovoltaic array, to provide astronomical data in the ultraviolet and X-ray wavelengths filtered out by the atmosphere. In 1969, the Odeillo solar furnace, located in Odeillo, France was fabricated, featuring an 8-story parabolic mirror. By 1970, Dr. Elliot Berman, with the Exxon Corporation, designed a significantly less costly solar cell, reducing the price from $100 a watt to $20 a watt. Solar cells began to power navigation warning lights and horns on many offshore gas and oil rigs, lighthouses, railroad crossings and domestic solar applications were appearing more feasible in locations remote from a grid-connection.
A cadmium sulfide (CdS) photovoltaic system is installed to operate an educational television at a village school in Niger in 1972. The Institute of Energy Conversion was also established in 1972 at the University of Delaware to perform research and development on thin-film photovoltaic (PV) and solar thermal systems, becoming the world's first laboratory dedicated to PV research and development. The University of Delaware built "Solar One" in 1973, one of the world's first photovoltaic (PV) powered residences. The system is a PV/thermal hybrid. The roof-integrated arrays fed surplus power through a special meter to the electric company during the day and purchased power from the electric company at night. In addition to electricity, the arrays acted as flat-plate thermal collectors, with fans blowing the warm air from over the array to phase-change heat-storage bins.
The NASA Lewis Research Center installed 83 photovoltaic power systems on all continents except Australia in 1976. These systems support diverse applications: as vaccine refrigeration, , and classroom television, grain milling, , medical clinic lighting, room lighting, telecommunications, water pumping, and vaccine refrigeration. At that time, David Carlson and Christopher Wronski, of RCA Laboratories, fabricated the first amorphous silicon photovoltaic cells. A year later in 1977, the U.S. Department of Energy launches a federal facility dedicated to harnessing power from the Sun, the Solar Energy Research Institute named "National Renewable Energy Laboratory." The cumulative global photovoltaic production capacity had exceeded 500 kilowatts in 1977. NASA's Lewis Research Center dedicated a 3.5-kilowatt photovoltaic (PV) system in 1978, when it was installed on the Papago Indian Reservation located in southern Arizona as the world's first village PV system. This system provided for water pumping and residential electricity in 15 homes until 1983, when grid-connections from the power utilities reached the village. The PV system was then dedicated exclusively to pumping water from a community well.
In 1980, ARCO Solar became the first company to produce more than 1 megawatt of photovoltaic modules in one year. At the University of Delaware, the first thin-film solar cell exceeds 10% efficiency with copper sulfide/cadmium sulfide. Paul MacCready built the first solar-powered aircraft in 1981, the Solar Challenger, and flew from France to England across the English Channel. The aircraft had over 16,000 solar cells mounted on its wings, which produced 3,000 watts of power. The first photovoltaic megawatt-scale power station connected on-line in Hisperia, California in 1982, with a 1-megawatt capacity system, developed by ARCO Solar, with modules on 108 dual-axis trackers. Australian Hans Tholstrup drove the first solar-powered car, the Quiet Achiever, almost 2,800 miles between Sydney and Perth in 20 days, 10 days faster than the first gasoline-powered car. The U.S. Department of Energy, along with an industry consortium, began operating Solar One, a 10-megawatt central-receiver demonstration project.
The project established the feasibility of power-tower systems, a solar-thermal electric or concentrating solar power technology. In 1988, the final year of operation, the system could be dispatched 96 percent of the time.  Volkswagen of Germany began testing photovoltaic arrays mounted on the roofs of Dasher station wagons, generating 160 watts for the ignition system. The Florida Solar Energy Center began supporting the U.S. Department of Energy's photovoltaics program in the application of systems engineering and worldwide photovoltaic production exceeded 9.3 megawatts. In 1983, ARCO Solar dedicated a 6-megawatt photovoltaic substation in central California. The 120-acre, unmanned facility supplied the Pacific Gas & Electric Company's utility grid with enough power for 2,000-2,500 homes. Solar Design Associates constructed an independent, 4-kilowatt powered home in the Hudson River Valley, and worldwide photovoltaic production exceeded 21.3 megawatts with sales of more than $250 million.
The Sacramento Municipal Utility District commissioned its first 1-megawatt photovoltaic electricity generating facility in 1984. The next year, 1985, the University of South Wales breaks the 20 percent efficiency barrier for silicon solar cells in accordance with the PV cell calibration of 1-Sun conditions, a total irradiance of 1 Sun or 1000 W/m
. The world's then largest solar thermal facility, located in Kramer Junction, California, was commissioned in 1986. The solar field contained rows of mirrors that concentrated the Sun's energy onto a system of pipes circulating a heat transfer fluid. The heat transfer fluid was used to produce steam, which powered a conventional turbine to generate electricity. ARCO Solar releases the G-4000--the world's first commercial thin-film power module. Dr. Alvin Marks received patents in 1988 for two solar power technologies he developed: Lepcon and Lumeloid. Lepcon consists of glass panels covered with a vast array of millions of aluminum or copper strips, each less than a micron or thousandth of a millimeter wide.
As sunlight hits the metal strips, the energy in the light was transferred to electrons in the metal that escape at one end in the form of electricity. Lumeloid used a similar approach but substituted cheaper, film sheets of plastic for the glass panels and covered the plastic with conductive polymers, or long chains of molecular plastic units. In 1991, President George Bush re-designated the U.S. Department of Energy's Solar Energy Research Institute as the National Renewable Energy Laboratory. The following year, 1992, the University of South Florida developed a 15.9 percent efficient thin-film photovoltaic cell made of cadmium telluride, breaking the 15 percent barrier for this technology. A 7.5-kilowatt prototype dish system using an advanced stretched-membrane concentrator becomes operational. Pacific Gas & Electric completed installation of the first grid-supported photovoltaic system in 1993 at Kerman, California. The 500-kilowatt system was the first "distributed power" effort. The next year, 1994, the National Renewable Energy Laboratory (formerly the Solar Energy Research Institute) completed construction of a Solar Energy Research Facility that was recognized as the most energy-efficient of all U.S. government buildings. The solar electric system was companion to a passive solar design. Subsequently, a solar dish generator using a free-piston Stirling engine was connected to an electric utility grid. The National Renewable Energy Laboratory developed a solar cell, made from gallium indium phosphide and gallium arsenide that becomes the first one to exceed the 30 percent conversion efficiency barrier. In 1996, the world's most advanced solar-powered airplane, the Icare, flew over Germany. The wings and tail surfaces of the Icare are covered by 3,000 super-efficient solar cells, with a total area of 21 m
. The U.S. Department of Energy, along with an industry consortium, began operating Solar Two, an upgrade of Solar One, concentrating on the solar power tower project. Operated until 1999, Solar Two demonstrated how solar energy can be stored efficiently and economically so that power can be distributed when sunlight is compromised. The remote-controlled, solar-powered aircraft, "Pathfinder" sets an altitude record, 80,000 feet, on its 39th consecutive flight on August 6,1998, in Monrovia, California. This altitude is higher than any prop-driven aircraft thus far. Subhendu Guha, a noted scientist for his pioneering work in amorphous silicon, led the invention of flexible solar shingles, a roofing material and state-of-the-art technology for converting sunlight to electricity. In 1999, Construction was completed on 4 Times Square, the tallest skyscraper built during the 1990s in New York City, and incorporated more energy-efficient building techniques than any other commercial skyscraper and also includes building-integrated photovoltaic (BIPV) panels on the 37th through 43rd floors on the south and west-facing facades that generate a portion of the buildings power.
Spectrolab, Inc. and the National Renewable Energy Laboratory fabricated a photovoltaic solar cell in 1999 that converted over 32 percent of the available sunlight into electricity. This high conversion efficiency was achieved by layering three photovoltaic materials into one solar cell, which performed most efficiently when received sunlight was concentrated 50 times. To use these cells in practical applications, the cell is mounted in a device with lenses and/or mirrors to concentrate sunlight onto the cell and these "concentrator" systems are mounted on tracking systems that keep them pointed toward the Sun. Later that year, the National Renewable Energy Laboratory achieved a new efficiency record for thin-film photovoltaic solar cells. Their record setting 18.8 percent efficiency for a prototype solar cell out-performed the previous record by more than 1 percent. By the end of the 20th century, the cumulative global photovoltaic production capacity had reached 1000 megawatts. First Solar began production in the year 2000 at Perrysburg, Ohio, the world's largest photovoltaic manufacturing plant with an estimated capacity of producing enough solar panels each year to generate 100 megawatts of power.
At the International Space Station, astronauts installed solar panels on what would be the largest solar power array deployed in space. Each array section was comprised of 32,800 solar cells. Sandia National Laboratories developed an inverter for solar electric systems that increases the safety of the systems during a power outage. Inverters convert the direct current (DC) electrical output from solar systems into alternating current (AC), which is the grid-connection electrical current standard. Two new thin-film solar modules, developed by BP Solarex, break previous performance records. The company's 0.5-square-meter module achieves 10.8 % conversion efficiency, the highest in the world for thin-film modules of its kind. And its 0.9-square-meter module achieved 10.6% conversion efficiency and a power output of 91.5 watts is the highest power output for any thin-film module in the world. In Morrison, Colorado, a 12-kilowatt solar electric system, the largest residential installation in the United States, was registered with the U.S. Department of Energy's "Million Solar Roofs" program.
The system provides most of the electricity for the 6,000-square-foot home and family of eight. Home Depot started selling residential solar power systems in three of its stores in San Diego, California during 2001, and a year later sales expanded to 61 other stores nationwide. NASA's solar-powered aircraft, Helios, set a world record for non-rocket-powered aircraft: 96,863 feet, more than 18 miles high. The National Space Development Agency of Japan, or NASDA, announced plans to develop a satellite-based solar power system that would beam energy back to Earth. A satellite carrying large solar panels would transmit the power with a laser to an airship at an altitude of about 12 miles that would then transmit the power to Earth.
TerraSun LLC developed a unique method of using holographic films to concentrate sunlight onto a solar cell, typically achieved with Fresnel lenses or mirrors to concentrate sunlight. TerraSun demonstrated that the use of holographic optics allows more selective use of the sunlight, allowing light not needed for power production to pass through the transparent modules. This capability allows solar modules to be integrated into buildings as functional skylights. PowerLight Corporation connected the world's largest hybrid system that combines the power from both wind and solar energy online in Hawaii. The grid-connected system is unique because the solar energy capacity of 175 kilowatts exceeds the wind energy capacity of 50 kilowatts. Hybrid power systems combine the merits of both energy systems to maximize available power. British Petroleum (BP) and BP Solar announced the opening of a service station in Indianapolis that features a solar-electric canopy. The Indianapolis station is the first U.S. "BP Connect" store, a model that BP intends to use for all new or significantly renovated BP service stations. The canopy was constructed from translucent photovoltaic modules made of thin films of silicon deposited onto glass.
In 2002, NASA successfully conducted two tests of a solar-powered, remote-controlled aircraft named Pathfinder Plus. While the first test in July enabled researchers to demonstrate the aircraft as a high-altitude platform for telecommunications technologies, the second test in September, demonstrated an aerial imaging system for coffee growers. Union Pacific Railroad installed 350 blue-signal rail yard lanterns that incorporate energy saving light-emitting diode (LED) technology with solar cells, at North Platt, Nebraska, and at the largest rail yard in the United States. ATS Automation Tooling Systems Inc. in Canada commercialized an innovative method of producing solar cells, called Spheral Solar technology. The technology bonds silicon beads between two sheets of aluminum foil and assures lower costs because of reduced use of silicon relative to conventional multicrystalline silicon solar cells. This technology was previously championed by Texas Instruments (TI) in the early 1990s however, despite U.S. Department of Energy (DOE) funding, TI abandoned the initiative. The 38.7-kilowatt White Bluffs Solar Station went online at Richland, Washington followed by one the largest rooftop solar power systems in the United States installed by the PowerLight Corporation during 2002, a 1.18 megawatt system, at the Santa Rita Jail in Dublin, California.
Future expectations concur that all buildings should be constructed to combine energy-efficient design and construction practices and renewable energy technologies for a net-zero energy building. In theory, any building should conserve enough and produce its own energy supply to create a new generation of cost-effective buildings that have zero net annual need for non-renewable energy. Photovoltaics research and development is experimenting with alternative materials, cell designs, and strategic approaches to the production of solar power. Every surface that is exposed to the Sun, from the fabrics worn as clothing to the rigid materials that enclose buildings and vehicles, can contribute to the production of power that is clean and safe.