Solar technology isn’t new. Its history spans from the 7th
Century B.C. to today. We started out concentrating the
sun’s heat with glass and mirrors to light fires. Today, we
have everything from solar-powered buildings to solarpowered vehicles.

Byron Stafford,
NREL / PIX10730

Byron Stafford,
NREL / PIX05370

Here you can learn more about the milestones in thehistorical development of solar technology, century by
century, and year by year. You can also glimpse the future.
This timeline lists the milestones in the historical developmentof solar technology from the 7th Century B.C. to the 1200s A.D.
7th Century B.C.

Magnifying glass used to concentrate sun’s rays to make fire and to burn ants.

3rd Century B.C.
Courtesy of
New Vision
Technologies, Inc./
Images ©2000
NVTech.com

Greeks and Romans use burning mirrors to light torches for religious purposes.

2nd Century B.C.
As early as 212 BC, the Greek scientist, Archimedes, used the reflective
properties of bronze shields to focus sunlight and to set fire to wooden ships
from the Roman Empire which were besieging Syracuse. (Although no proofof such a feat exists, the Greek navy recreated the experiment in 1973 andsuccessfully set fire to a wooden boat at a distance of 50 meters.)

20 A.D.
Chinese document use of burning mirrors to light torches for religious
purposes.

1st to 4th Century 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. For an example, see informationon the http://www.hum.huji.ac.il/archaeology/zippori/RomanSeph.htm Zippori in
the Roman Period from the Hebrew University of Jerusalem.
Courtesy of Susan Sczepanski , NREL

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.

1200s A.D.
The Anasazi cliff dwellings demonstratepassive solar design. (John Thornton, NREL
/ PIX 03544)

Ancestors of Pueblo people called Anasazi in North America live in south-facing
cliff dwellings that capture the winter sun.

This timeline lists the milestones in the historical developmentof solar technology from 1767 to 1891.
1767

Swiss scientist Horace de Saussure was credited with building the world’s firstsolar collector, later used by Sir John Herschel to cook food during his South Africa
expedition in the 1830s. See the Solar Cooking Archive for more information on
http://solarcooking.org/saussure.htm Sassure and His Hot Boxes of the 1700s.

Illustration
courtesy of Kevin Porter,
Solar Cookers, International

1816

On September 27, 1816, Robert Stirling applied for a patent for his economiser
at the Chancery in Edinburgh, Scotland. By trade, Robert Stirling was actuallya minister in the Church of Scotland and he continued to give services until
he was eighty-six years old! But, in his spare time, he built heat engines in his
home workshop. Lord Kelvin used one of the working models during some of
his university classes. This engine was later used in the dish/Stirling system, asolar thermal electric technology that concentrates the sun’s thermal energy
in order to produce power.

1839

French scientist Edmond Becquerel discovers the photovoltaic effect while
experimenting with an electrolytic cell made up of two metal electrodes placedin an electricity-conducting solution—electricity-generation increased when
exposed to light.

1860s

French mathematician August Mouchet proposed an idea for solar-powered steam
engines. In the following two decades, he and his assistant, Abel Pifre, constructed
the first solar powered engines and used them for a variety of applications. These
engines became the predecessors of modern parabolic dish collectors.

1873

Willoughby Smith discovered the photoconductivity of selenium.

1876

William Crylls Adams,
Courtesy of John Perlin
2002 From Space to Earth:
The Story of Solar Electricity

1876 William Grylls Adams and Richard Evans Day discover that selenium
produces electricity when exposed to light. Although selenium solar cells failed
to convert enough sunlight to power electrical equipment, they proved that asolid material could change light into electricity without heat or moving parts.

1880

Samuel P. Langley,
Courtesy of NASA

Bolometer,
Courtesy of NASA

Samuel P. Langley, invents the bolometer, which is used to measure light fromthe faintest stars and the sun’s heat rays. It consists of a fine wire connected
to an electric circuit. When radiation falls on the wire, it becomes very slightly
warmer. This increases the electrical resistance of the wire.

1883
Heinrich Hertz,
Courtesy of NASA/
Goddard Space
Flight Center

Charles Fritts, an American inventor, described the first solar cells made fromselenium wafers.

1887

Heinrich Hertz discovered that ultraviolet light altered the lowest voltage capable of causing a spark to jump between two metal electrodes.

1891
Solar Water Heater
Courtesy of John Perlin/
Butti Solar Archives

Baltimore inventor Clarence Kemp patented the first commercial solar
water heater. For more information on the water heater, see the
http://www.californiasolarcenter.org/history_solarthermal.html California
Solar Center.

This timeline lists the milestones in the historical developmentof solar technology in the 1900s.
1904

Wilhelm Hallwachs discovered that a combination of copper and cuprous oxide
is photosensitive.

Albert Einstein, courtesy of
the Lotte Jacobi Archives,
University of Hampshire

1905

Albert Einstein published his paper on the photoelectric effect (along with apaper on his theory of relativity).

Theory of
Relativity equation

1908

1908 William J. Bailley of the Carnegie Steel Company invents a solar collector
with copper coils and an insulated box—roughly, it’s present design.
Solar collector

1914

The existence of a barrier layer in photovoltaic devices was noted.

1916

Robert Millikan provided experimental proof of the photoelectric effect.
©1916 by The American Physical Society

1918

Polish scientist Jan Czochralski developed a way to grow single-crystal
silicon. For more information on Czochralski, see the article
http://rekt.pol.lublin.pl/users/ptwk/art2.htm Professor Jan Czolchralski(1885-1953) and His Contribution to the Art and Science of Crystal Growth.

1921

Albert Einstein wins the Nobel Prize for his theories (1904 research and technical paper) explaining the photoelectric effect.

Jan Czochralski,
courtesy of Debra Kaiser,
AACG newsletter

1932

Audobert and Stora discover the photovoltaic effect in cadmium sulfide (CdS).
Single-crystal silicon

1947

1947 Passive solar buildings in the United States were in such demand, as aresult of scarce energy during the prolonged W.W.II, that Libbey-Owens-Ford
Glass Company published a book entitled Your Solar House, which profiled
forty-nine of the nation’s greatest solar architects.
http://www.californiasolarcenter.org/history_solarthermal.html.

1953

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.

1954

Bell Labs scientists, Daryl Chaplin, Calvin
Fuller, and Gerald Pearson, courtesy ofJohn Perlin

1954 Photovoltaic technology is born in the United States when Daryl Chapin,
Calvin Fuller, and Gerald Pearson develop the silicon photovoltaic (PV) cell at
Bell Labs—the first solar cell capable of converting enough of the sun’s energy
into power to run everyday electrical equipment. Bell Telephone Laboratories
produced a silicon solar cell with 4% efficiency and later achieved 11%
efficiency. See the http://www.californiasolarcenter.org/history_pv.html for
more information.

1955

Western Electric began to sell commercial licenses for silicon photovoltaic (PV)technologies. Early successful products included PV-powered dollar billchangers and devices that decoded computer punch cards and tape.
Bell Labs
silicon solar cellMid-1950s

Architect Frank Bridgers designed the world’s first commercial office building
using solar water heating and passive design. This solar system has been
continuously operating since that time and the Bridgers-Paxton Building, is
now in the National Historic Register as the world’s first solar heated officebuilding.

1956

William Cherry, U.S. Signal Corps Laboratories, approaches RCA Labs’ Paul
Rappaport and Joseph Loferski about developing photovoltaic cells for
proposed orbiting Earth satellites.
William Cherry,courtesy ofMark Fitzgerald

1957

Hoffman Electronics achieved 8% efficient photovoltaic cells.

1958

T. Mandelkorn, U.S. Signal Corps Laboratories, fabricates n-on-p silicon
photovoltaic cells (critically important for space cells; more resistant toradiation).

1958

Hoffman Electronics achieves 9% efficient photovoltaic cells.

1958

The Vanguard I space satellite used a small (less than one watt) array to
power its radios. Later that year, Explorer III, Vanguard II, and Sputnik-3 werelaunched with PV-powered systems on board. Despite faltering attempts tocommercialize the silicon solar cell in the 1950s and 60s, it was usedsuccessfully in powering satellites. It became the accepted energy source forspace applications and remains so today. For more information, see theSmithsonian National Air and Space Museum’s information on
http://www.nasm.si.edu/nasm/dsh/artifacts/SS-vanguard.htm “Vanguard 1”.

1959

Hoffman Electronics achieves 10% efficient, commercially available
photovoltaic cells. Hoffman also learns to use a grid contact, reducing theseries resistance significantly.

1959
Courtesy of http://www.suite101.com

On August 7, the Explorer VI satellite is launched with a photovoltaic array of
9600 cells (1 cm x 2 cm each). Then, on October 13, the Explorer VII satellite
is launched.

1960

Hoffman Electronics achieves 14% efficient photovoltaic cells.

1960

Silicon Sensors, Inc., of Dodgeville, Wisconsin, is founded. It starts producing
selenium and silicon photovoltaic cells.

1962Bell Telephone Laboratories launches the first telecommunications satellite,
the Telstar (initial power 14 watts).

1963

Sharp Corporation succeeds in producing practical silicon photovoltaic
modules.

1963Japan installs a 242-watt, photovoltaic array on a lighthouse, the world’s largest array at that time.

1964

NASA launches the first Nimbus spacecraft—a satellite powered by a 470-wattphotovoltaic array. See NASA’s http://nssdc.gsfc.nasa.gov/earth/nimbus.html“Nimbus Program” for more information.

1965

Peter Glaser conceives the idea of the satellite solar power station. For more
information, see DOE’s reference brief,
http://www.eere.energy.gov/consumerinfo/refbriefs/l123.html “Solar Power
Satellites”.

1966

NASA launches the first Orbiting Astronomical Observatory, powered by a
1-kilowatt photovoltaic array, to provide astronomical data in the ultraviolet
and X-ray wavelengths filtered out by the earth’s atmosphere.

1969

The Odeillo solar furnace, located in Odeillo, France was constructed.
This featured an 8-story parabolic mirror.

1970s
Allan Lawandowski / PIX06409

Dr. Elliot Berman, with help from Exxon Corporation, designs a significantly
less costly solar cell, bringing price down from $100 a watt to $20 a watt. Solarcells begin to power navigation warning lights and horns on many offshore
gas and oil rigs, lighthouses, railroad crossings and domestic solar applications
began to be viewed as sensible applications in remote locations where gridconnected utilities could not exist affordably.

1972

The French install a cadmium sulfide (CdS) photovoltaic system to operate an
educational television at a village school in Niger.

1972

The Institute of Energy Conversion is established at the University of Delawareto 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.

1973

The University of Delaware builds “Solar One,” 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 utility
during the day and purchased power from the utility at night. In addition toelectricity, the arrays acted as flat-plate thermal collectors, with fans blowing
the warm air from over the array to phase-change heat-storage bins.

1976

The NASA Lewis Research Center starts installing 83 photovoltaic power systems on every continent except Australia. These systems provide such diverse
applications as vaccine refrigeration, room lighting, medical clinic lighting, telecommunications, water pumping, grain milling, and classroom television. The
Center completed the project in 1995, working on it from 1976-1985 and thenagain from 1992-1995.

1976

David Carlson and Christopher Wronski, RCA Laboratories, fabricate first
amorphous silicon photovoltaic cells.
Warren Gretz, NREL / PIX04501

1977

The U.S. Department of Energy launches the Solar Energy Research Institutehttp://www.nrel.gov/ “National Renewable Energy Laboratory”, a federal
facility dedicated to harnessing power from the sun.

1977

Total photovoltaic manufacturing production exceeds 500 kilowatts.

1978

1978 NASA’s Lewis Research Center dedicates a 3.5-kilowatt photovoltaic (PV)system it installed on the Papago Indian Reservation located in southern
Arizona—the world’s first village PV system. The system is used to provide
for water pumping and residential electricity in 15 homes until 1983, when grid
power reached the village. The PV system was then dedicated to pumping
water from a community well.

1980

ARCO Solar becomes the first company to produce more than 1 megawatt ofphotovoltaic modules in one year.
Courtesy of http://www.otherpower.com

1980

At the University of Delaware, the first thin-film solar cell exceeds
10% efficiency using copper sulfide/cadmium sulfide.

1981

Paul MacCready builds the first solar-powered aircraft—the Solar
Challenger—and flies it 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 Smithsonian Institute National Air and Space Museum hasa photo of the http://www.nasm.edu/nasm/aero/aircraft/maccread.htm “Solar
Challenger” in flight.
Courtesy of ©1988 National Air and Space
Museum, Smithsonian Institution

1982

The first, photovoltaic megawatt-scale power station goes on-line in Hisperia,
California. It has a 1-megawatt capacity system, developed by ARCO Solar, withmodules on 108 dual-axis trackers.

1982

Courtesy of http://www.speedace.info/

Australian Hans Tholstrup drives 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 to do so. Tholstrup is the founder ofthe http://www.wsc.org.au/2003/home.solar “World Solar Challenge” inAustralia, considered the world championship of solar car racing.

1982

Sandia National Laboratories / PIX00036

The U.S. Department of Energy, along with an industry consortium, begins
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 ofoperation, the system could be dispatched 96% of the time. For more
information, see www.eere.energy.gov/erec/factsheets/csp.html“Concentrating Solar Power: Energy From Mirrors” andhttp://www.energylan.sandia.gov/sunlab/Snapshot/STFUTURE.htm “Solar Two
Demonstrates Clean Power for the Future”.
– Photo caption: Solar One, a 10-megawatt central receiver power tower is located in Daggett, CA.
(Sandia National Laboratories / PIX00036)

1982

Volkswagen of Germany begins testing photovoltaic arrays mounted on theroofs of Dasher station wagons, generating 160 watts for the ignition system.

1982

The Florida Solar Energy Center’s
http://www.fsec.ucf.edu/About/quals/index.htm#recentcon “Southeast
Residential Experiment Station” begins supporting the U.S. Department ofEnergy’s photovoltaics program in the application of systems engineering.

1982

Worldwide photovoltaic production exceeds 9.3 megawatts.

1983

ARCO Solar dedicates a 6-megawatt photovoltaic substation in central
California. The 120-acre, unmanned facility supplies the Pacific Gas & ElectricCompany’s utility grid with enough power for 2,000-2,500 homes.

1983

Solar Design Associates completes a stand-alone, 4-kilowatt powered home in
the Hudson River Valley.

1983

Worldwide photovoltaic production exceeds 21.3 megawatts, with sales ofmore than $250 million.

1984

The Sacramento Municipal Utility District commissions its first 1-megawatt
photovoltaic electricity generating facility.

1985

The University of South Wales breaks the 20% efficiency barrier for siliconsolar cells under 1-sun conditions.

1986

1986 The world’s largest solar thermal facility, located in Kramer Junction,
California, was commissioned. The solar field contained rows of mirrors thatconcentrated the sun’s energy onto a system of pipes circulating a heattransfer fluid. The heat transfer fluid was used to produce steam, whichpowered a conventional turbine to generate electricity.
– Photo Caption: This solar power plant located in Kramer Junction, California, is the largest of ninesuch plants built in the 1980’s. During operation, oil in the receiver tubes collects the concentrated
solar energy as heat and is pumped to a power block located at the power plant for generating
electricity. (Warren Gretz, NREL / PIX01224)
Warren Gretz, NREL / PIX01224

1986

ARCO Solar releases the G-4000—the world’s first commercial thin-film
power module.

1988

Dr. Alvin Marks receives patents for two solar power technologies hedeveloped: Lepcon and Lumeloid. Lepcon consists of glass panels covered witha 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 inthe light is transferred to electrons in the metal, which escape at one end in theform of electricity. Lumeloid uses a similar approach but substitutes cheaper,film-like sheets of plastic for the glass panels and covers the plastic with
conductive polymers, long chains of molecular plastic units.

1991

President George Bush redesignates the U.S. Department of Energy’s Solar
Energy Research Institute as the National Renewable Energy Laboratory.

1992

1992 University of South Florida develops a 15.9% efficient thin-film
photovoltaic cell made of cadmium telluride, breaking the 15% barrier for the
first time for this technology.
– Photo caption: Thin-film modules, such as this one made with amorphous silicon, can be deposited on a variety of low-cost substrates, including glass and flexible plastic sheets. (Warren Gretz,
NREL / PIX03541)

Warren Gretz,
NREL / PIX03541

1992

A 7.5-kilowatt prototype dish system using an advanced stretched-membraneconcentrator becomes operational.
Sandia NationalLabs / PIX01728

1993

1993 Pacific Gas & Electric completes installation of the first grid-supported
photovoltaic system in Kerman, California. The 500-kilowatt system was thefirst “distributed power” effort.
– Photo caption: Pacific Gas and Electric Company (PG&E) installed a 500-kilowatt photovoltaic
system at its Kerman substation to reinforce a weak feeder. PG&E found that distributed systems
like this have measurable benefits such as increased system reliability and peak-shaving capabilities. (Terry O’Rourke / PIX00253)

1994
Terry O’Rourke / PIX00253

Dave Parsons / PIX06995

The National Renewable Energy Laboratory (formerly the Solar Energy
Research Institute) completes construction of its
http://www.nrel.gov/buildings/highperformance/serf.html “Solar Energy
Research Facility”, which was recognized as the most energy-efficient of all
U.S. government buildings worldwide. It features not only solar electric
system, but also a passive solar design.

1994

First solar dish generator using a free-piston Stirling engine is tied to a utility grid.

1994

The National Renewable Energy Laboratory develops a solar cell—made fromgallium indium phosphide and gallium arsenide—that becomes the first one toexceed 30% conversion efficiency.

1996
Warren Gretz, NREL / PIX03302

The world’s most advanced solar-powered airplane, the Icare, flew overGermany. The wings and tail surfaces of the Icare are covered by 3,000
super-efficient solar cells, with a total area of 21 m2. See
http://www.ifb.uni-stuttgart.de/icare/pictures/ica-fl2.jpg “Solar Aircraft of
the University of Stuttgart” for more information about Icare.

1996

The U.S. Department of Energy, along with an industry consortium, begins
operating Solar Two—an upgrade of its Solar One concentrating solar power
tower project. Operated until 1999, Solar Two demonstrated how solar energy
can be stored efficiently and economically so that power can be produced evenwhen the sun isn’t shining. It also fostered commercial interest in power
towers. See http://www.energylan.sandia.gov/sunlab/Snapshot/STFUTURE.htm“Solar Two Demonstrates Clean Power for the Future” for more information.
– Photo Caption: The Solar Two project will improve the 10-megawatt Solar One central receiverplant in Daggett, CA. A field of mirrored heliostats focuses sunlight on a 300-foot (91 meter) tower,
which will be filled with molten nitrate salt. The salt flows like water and can be heated to 1050
degrees F. The salt is pumped through a steam generator to produce the steam to power a conventional, high-efficiency steam turbine to produce electricity. (566 degrees C). (Sandia National
Laboratories / PIX01701)
Sandia National Laboratories / PIX01701

1998

The remote-controlled, solar-powered aircraft, “Pathfinder” sets an altitude
record, 80,000 feet, on its 39th consecutive flight on August 6, in Monrovia,
California. This altitude is higher than any prop-driven aircraft thus far.

1998

United Solar Systems
Corporation / PIX03636

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.
– Photo caption: The PV shingles mount directly on to the roof and take the place of asphalt shingles.
The system is connected to the utility grid through an inverter and produces electricity on customer’sside of the meter. United Solar Systems Corporation / PIX03636)

1999

1999 Construction was completed on 4 Times Square, the tallest skyscraper built
in the 1990s in New York City. It incorporates 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 southand west-facing facades that produce a portion of the buildings power.
– Photo Caption: 4 Times Squares most advanced feature is the photovoltaic skin, a system thatuses thin-film PV panels to replace traditional glass cladding material. The PV curtain wall extends
from the 35th to the 48th floor on the south and east walls of the building, making it a highly visible
part of the midtown New York skyline. The developer, the Durst Organization, has implemented
a wide variety of healthy building and energy efficiency strategies. Kiss + Cathcart Architects
designed the building’s PV system in collaboration with Fox and Fowle, the base buildingarchitects. Energy Photovoltaics of Princeton, NJ, developed the custom PV modules.
(Kiss + Cathcon - Architects / PIX06456)

1999
Kiss + Cathcon - Architects /PIX06456

Spectrolab, Inc. and the National Renewable Energy Laboratory develop a
photovoltaic solar cell that converts 32.3 percent of the sunlight that hits it into
electricity. The high conversion efficiency was achieved by combining threelayers of photovoltaic materials into a single solar cell. The cell performed mostefficiently when it received sunlight concentrated to 50 times normal. To use
such cells in practical applications, the cell is mounted in a device that uses lenses
or mirrors to concentrate sunlight onto the cell. Such “concentrator” systems
are mounted on tracking systems that keep them pointed toward the sun.

1999

Warren Gretz, NREL / PIX00183

The National Renewable Energy Laboratory achieves a new efficiency record forthin-film photovoltaic solar cells. The measurement of 18.8 percent efficiency forthe prototype solar cell topped the previous record by more than 1 percent.

1999

Cumulative worldwide installed photovoltaic capacity reaches 1000 megawatts.

This timeline lists the milestones in the historical development ofsolar technology in the 2000s.
2000
Courtesy of NASAFirst Solar begins production in Perrysburg, Ohio, at the world’s largest
photovoltaic manufacturing plant with an estimated capacity of producing
enough solar panels each year to generate 100 megawatts of power.

2000

At the International Space Station, astronauts begin installing solar panels on
what will be the largest solar power array deployed in space. Each “wing” of
the array consists of 32,800 solar cells.

2000

Sandia National Laboratories develops a new inverter for solar electric systems
that will increase 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 standard current for household wiringand for the power lines that supply electricity to homes.
Sandia National Labs, PIX10809

2000

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 apower output of 91.5 watts — the highest power output for any thin-film
module in the world.

2000

A family in Morrison, Colorado, installs a 12-kilowatt solar electric system on its
home—the largest residential installation in the United States to be registeredwith the U.S. Department of Energy’s http://www.millionsolarroofs.com/ “Million
Solar Roofs” program. The system provides most of the electricity for the 6,000square-foot home and family of eight.

2001

Home Depot begins selling residential solar power systems in three of its stores in
San Diego, California. A year later it expands sales to include 61 stores nationwide.

2001
Courtesy of NASA, Dryden Flight ResearchCenter Photo Collection

NASA’s solar-powered aircraft—Helios sets a new world record for non-rocketpowered aircraft: 96,863 feet, more than 18 miles high.
– Photo caption: The Helios Prototype flying wing is shown near the Hawaiian Islands during its firsttest flight on solar power. (Photo Courtesy of NASA, Dryden Flight Research Center Photo Collection)

2001

The National Space Development Agency of Japan, or NASDA, announces plans
to develop a satellite-based solar power system that would beam energy back to
Earth. A satellite carrying large solar panels would use a laser to transmit
the power to an airship at an altitude of about 12 miles, which would thentransmit the power to Earth.

2001

TerraSun LLC develops a unique method of using holographic films toconcentrate sunlight onto a solar cell. Concentrating solar cells typically use
Fresnel lenses or mirrors to concentrate sunlight. TerraSun claims that the useof holographic optics allows more selective use of the sunlight, allowing light notneeded for power production to pass through the transparent modules. This
capability allows the modules to be integrated into buildings as skylights.

2001

PowerLight Corporation places online in Hawaii the world’s largest hybrid
system that combines the power from both wind and solar energy. The gridconnected system is unusual in that its solar energy capacity—175 kilowatts—
is actually larger than its wind energy capacity of 50 kilowatts. Such hybrid
power systems combine the strengths of both energy systems to maximize theavailable power.
PowerLight Corporation / PIX06431

2001

British Petroleum (BP) and BP Solar announce the opening of a service stationin 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 orsignificantly revamped BP service stations. The canopy is built using translucent
photovoltaic modules made of thin films of silicon deposited onto glass.
Warren Gretz,
NREL / PIX11979– Photo Caption: The PowerView Semi-Transparent Photovoltaic Module, developed by NREL and
BP Solar, is a novel system that serves as a roof or window while creating power for a building. BP
has to date incorporated the system in more that 150 of its service stations and the panels areenvisioned to become a functional replacement for conventional glass in walls, canopies, atriums,
entrances and facades in commercial and residential architecture. (Warren Gretz, NREL / PIX11979)

2002

Courtesy of NASA
Dryden Flight
Research Center
Photo Collection

NASA successfully conducts two tests of a solar-powered, remote-controlled
aircraft called Pathfinder Plus. In the first test in July, researchers
demonstrated the aircraft’s use as a high-altitude platform for telecommunications technologies. Then, in September, a test demonstrated
its use as an aerial imaging system for coffee growers.
– Photo Caption: The Pathfinder Plus is a lightweight, solar-powered, remotely piloted flying wing
aircraft that is demonstrating the technology of applying solar power for long-duration, high-altitude
flight. This solar-powered aircraft could stay airborne for weeks or months on scientific sampling
and imaging missions. Solar arrays covering most of the upper wing surface provide power forthe aircraft’s electric motors, avionics, communications and other electronic systems. It also has abackup battery system that can provide power for between two and five hours to allow limitedduration flight after dark. (Photo Courtesy of NASA, Dryden Flight Research Center Photo Collection)

2002

Union Pacific Railroad installs 350 blue-signal rail yard lanterns, which incorporate
energy saving light-emitting diode (LED) technology with solar cells, at its North
Platt, Nebraska, rail yard—the largest rail yard in the United States.

2002

Courtesy of
www.atsautomation.com

ATS Automation Tooling Systems Inc. in Canada starts to commercialize an
innovative method of producing solar cells, called Spheral Solar technology.
The technology—based on tiny silicon beads bonded between two sheets ofaluminum foil—promises lower costs due to its greatly reduced use of siliconrelative to conventional multicrystalline silicon solar cells. The technology is
not new. It was championed by Texas Instruments (TI) in the early 1990s. But
despite U.S. Department of Energy (DOE) funding, TI dropped the initiative.
See the DOE http://www.nrel.gov/pvmat/ti.html “Photovoltaic Manufacturing
Technology” Web site.

2002

The largest solar power facility in the Northwest—the 38.7-kilowatt
White Bluffs Solar Station—goes online in Richland, Washington.

2001

Powerlight Corporation installs the largest rooftop solar power system in the
United States—a 1.18 megawatt system—at the Santa Rita Jail in Dublin,
California.
Courtesy ofPowerLight
Corporation /PIX12398– Photo Caption: In Spring 2002, Alameda County, CA successfully completed the fourth largest solar
electric system in the world atop the Santa Rita Jail in Dublin, California. This solar installation, theUnited States’ largest rooftop system, was commissioned to help Alameda County reduce and stabilize
future energy costs. This smart energy project reduces the jail’s use of utility-generated electricity by
30% through solar power generation and energy conservation. Clean energy is generated by a
1.18 Megawatt system consisting of three acres of solar electric or photovoltaic (PV) panels.
(Courtesy of PowerLight Corporation / PIX12398)

Here’s a look at the expected future direction of solar technology.
All buildings will be built to combine energy-efficient design and construction
practices and renewable energy technologies for a net-zero energy building. In
effect, the building will conserve enough and produce its own energy supply tocreate a new generation of cost-effective buildings that have zero net annual
need for non-renewable energy.

Chris Gunn Photography / PIX12165– Photo Caption: This home was built by students from the University of Colorado (CU) for the first
Solar Decathlon, a competition sponsored by the U.S. Department of Energy (DOE). Student teams arechallenged to integrate aesthetics and modern conveniences with maximum energy production and optimal
efficiency. Each collegiate team will build a uniquely designed 500-ft2 -- 800-ft2 house. Decathletes willtransported their houses to the National Mall in Washington D.C. for the competition in the fall of 2002.
The CU team took first prize in the competition overall. (Chris Gunn Photography / PIX12165)

Photovoltaics research and development will continue intense interest in new materials, cell designs, and novel approaches to solar material and product development. It is a future where the clothes you wear and your mode of transportation
can produce power that is clean and safe.
Technology roadmaps for the future outline the research and development pathto full competitiveness of concentrating solar power (CSP) with conventional
power generation technologies within a decade. The potential of solar power in
the Southwest United States is comparable in scale to the hydropower resource of
the Northwest. A desert area 10 miles by 15 miles could provide 20,000 megawattsof power, while the electricity needs of the entire United States could theoreticallybe met by a photovoltaic array within an area 100 miles on a side. Concentrating
solar power, or solar thermal electricity, could harness the sun’s heat energy toprovide large-scale, domestically secure, and environmentally friendly electricity.
– Photo Caption: This is the world’s largest solar power facility, located near Kramer Junction, CA.
The facility consists of five Solar Electric Generating Stations (SEGS), with a combined capacity of 150
megawatts. At capacity, that is enough power for 150,000 homes. The facility covers more than 1000
acres, with over 1 million square meters of collector surface. (Kramer Junction Company / PIX11070)
Kramer Junction Company / PIX11070

The price of photovoltaic power will be competitive with traditional sources ofelectricity within 10 years.
Solar electricity will be used to electrolyze water, producing hydrogen for fuelcells for transportation and buildings.

Richard Parish / PIX10732– Photo Caption: SunLine, a California transit agency, is being evaluated as they add state-of-the-art
hydrogen fuel cell buses to their fleets and set up infrastructure facilities for fueling and maintenance.
The hydrogen is produced at the site using solar-powered electrolysis and natural gas reforming.
Because fuel cell buses aren’t yet commercially available, these demonstration projects are used tobetter understand the technology and plan for the future. (Richard Parish / PIX10732)