Learn about the Solar Energy Advantage!

History of Solar Energy, Part II

In a prior article (History of Solar Energy, Part I)  I traced mankind’s first rudimentary approaches to using solar energy.  Those initial efforts depended exclusively on capture thermal solar energy – heat. 

 
Capturing and using thermal energy from the sun remains an import line of effort, but in 1839 a remarkable discovery provided the first hint that something more was possible.  In that year, French physicist Alexandre-Edmond Becquerel noted that certain materials produced small electrical currents when exposed to light.  This discovery led to his inventing a device which could electrically measure the intensity of light.

 
As cool as that was, the discovery was more of a scientific curiosity than something which could truly impact our daily lives.  But check out some of what happened after that:

1860s

French mathematician August Mouchet proposes an idea for solar-powered steam engines. In the next two decades, he and his assistant, Abel Pifre, will construct the first solar-powered engines for a variety of uses. The engines are the predecessors of modern parabolic dish collectors.

1873

Willoughby Smith discovers the photoconductivity of selenium.

1876

William Grylls Adams and Richard Evans Day discover that selenium produces electricity when exposed to light. Although selenium solar cells fail to convert enough sunlight to power electrical equipment, they prove that a solid material can change light into electricity without heat or moving parts.

1883

American inventor Charles Fritts describes the first solar cells made of selenium wafers.

1891

Baltimore inventor Clarence Kemp patents the first commercial solar water heater.

Early 1900s

1904

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

1905

Albert Einstein publishes his paper on the photoelectric effect, along with a paper on his theory of relativity.

1908

William J. Bailley of the Carnegie Steel Company invents a solar collector with copper coils and an insulated box, which is roughly the same collector design used today.

1914

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

1916

Robert Millikan provides experimental proof of the photoelectric effect.

1918

Polish scientist Jan Czochralski develops a way to grow single-crystal silicon.

1920s

1921

Albert Einstein wins the Nobel Prize for his theories explaining the photoelectric effect.

1930s

1932

Audobert and Stora discover the photovoltaic effect in cadmium sulfide.

1940s

1947

Because energy had become scarce during the long Second World War, passive solar buildings in the United States are in demand.

1950s

1953

Dr. Dan Trivich of 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

Photovoltaic technology is born in the United States when Daryl Chapin, Calvin Fuller, and Gerald Pearson develop the silicon photovoltaic (or PV) cell at Bell Labs — the first solar cell capable of generating enough power from the sun to run everyday electrical equipment. Bell Telephone Laboratories then produces a silicon solar cell with 6% efficiency and later, 11% efficiency.

1956

William Cherry of U.S. Signal Corps Laboratories approaches RCA Labs' Paul Rappaport and Joseph Loferski about developing photovoltaic cells for proposed Earth-orbiting satellites.

1958

T. Mandelkorn of U.S. Signal Corps Laboratories fabricates n-on-p (negative layer on positive layer) silicon photovoltaic cells, making them more resistant to radiation; this is critically important for cells used in space.

Hoffman Electronics achieves 9% efficient photovoltaic cells.

1959

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

1960s

1960

Hoffman Electronics achieves 14% efficient photovoltaic cells.

1963

Sharp Corporation succeeds in producing practical silicon PV modules.

1965

Peter Glaser conceives the idea of the satellite solar power station.

1969

A "solar furnace" is constructed in Odeillo, France; it features an eight-story parabolic mirror.

1970s

1970s

With help from Exxon Corporation, Dr. Elliot Berman designs a significantly less costly solar cell, bringing the price down from $100 per watt to $20 per watt. Solar cells begin powering navigation warning lights and horns on offshore gas and oil rigs, lighthouses, and railroad crossings. Domestic solar applications are considered good alternatives in remote areas where utility-grid connections are too costly.

1973

The University of Delaware builds "Solar One," a PV/thermal hybrid system. Roof-integrated arrays feed surplus power through a special meter to the utility during the day; power is purchased from the utility at night. In addition to providing electricity, the arrays are like flat-plate thermal collectors; fans blow warm air from over the array to heat storage bins.

1976

David Carlson and Christopher Wronski of RCA Laboratories produce the first amorphous silicon photovoltaic cells, which could be less expensive to manufacture than crystalline silicon devices.

1980s

1980

At the University of Delaware, the first thin-film solar cell exceeds 10% efficiency; it's made of copper sulfide and cadmium sulfide.

1982

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

In California, the U.S. Department of Energy and an industry consortium begin operating Solar One, a 10-megawatt central-receiver demonstration project. It establishes 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% of the time.

1983

ARCO Solar dedicates a 6-megawatt photovoltaic substation in central California. The 120-acre, unmanned facility supplies Pacific Gas & Electric Company's utility grid with enough power for up to 2,500 homes.

1985

Researchers at the University of South Wales break the 20% efficiency barrier for silicon solar cells.

1986

The world's largest solar thermal facility is commissioned in Kramer Junction, California. The solar field contains rows of mirrors that concentrate the sun's energy onto a system of pipes circulating a heat transfer fluid. The heat transfer fluid is used to produce steam, which powers a conventional turbine to generate electricity.

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

1988

Dr. Alvin Marks receives patents for two solar power technologies: Lepcon and Lumeloid. Lepcon consists of glass panels covered with millions of aluminum or copper strips, each less than a thousandth of a millimeter wide. As sunlight hits the metal strips, light energy is transferred to electrons in the metal, which escape at one end in the form of electricity. Lumeloid is similar but substitutes cheaper, film-like sheets of plastic for the glass panels and covers the plastic with conductive polymers.

1990s

1992

Researchers at the University of South Florida develop a 15.9% efficient thin-film photovoltaic cell made of cadmium telluride, breaking the 15% barrier for this technology.

1994

The first solar dish generator to use a free-piston Stirling engine is hooked up to a utility grid.

The National Renewable Energy Laboratory develops a solar cell made of gallium indium phosphide and gallium arsenide; it's the first one of its kind to exceed 30% conversion efficiency.

1998

Subhendu Guha, a scientist noted for pioneering work in amorphous silicon, leads the invention of flexible solar shingles, a roofing material and state-of-the-art technology for converting sunlight to electricity on buildings.

1999

Spectrolab, Inc., and the National Renewable Energy Laboratory develop a 32.3% efficient solar cell. The high efficiency results from combining three layers of photovoltaic materials into a single cell, which is most efficient and practical in devices with lenses or mirrors to concentrate the sunlight. The concentrator systems are mounted on trackers to keep them pointed toward the sun.

Researchers at the National Renewable Energy Laboratory develop a record-breaking prototype solar cell that measures 18.8% efficient, topping the previous record for thin-film cells by more than 1%. Cumulative installed photovoltaic capacity reaches 1000 megawatts, worldwide.

2000

Industry Researchers develop a new inverter for solar electric systems that increases safety during power outages. Inverters convert the direct current (DC) electrical output of solar systems to alternating current (AC) — the standard for household wiring as well as for power lines to homes.

Two new thin-film solar modules developed by BP Solarex break previous performance records. The company's 0.5-square-meter module has a 10.8% conversion efficiency — the highest in the world for similar thin-film modules. Its 0.9-square-meter module achieves 10.6% efficiency and a power output of 91.5 watts — the highest in the world for a thin-film module.

2001

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

TerraSun LLC develops a unique method of using holographic films to concentrate sunlight onto a solar cell. Fresnel lenses or mirrors are usually used to concentrate sunlight, but TerraSun claims that holographic optics are more selective, allowing light not needed for power production to pass through the transparent modules so they can be used as skylights.

PowerLight Corporation connects the world's largest hybrid solar-wind power system to the grid in Hawaii. Its solar energy capacity — 175 kilowatts — is larger than its wind energy capacity — 50 kilowatts; this is somewhat unusual for hybrid power systems.

2002

ATS Automation Tooling Systems Inc. in Canada begins commercializing spheral solar technology. Employing tiny silicon beads bonded between two sheets of aluminum foil, this solar-cell technology uses much less silicon than conventional multicrystalline silicon solar cells, thus potentially reducing costs. The technology was first championed in the early 1990s by Texas Instruments, but TI later discontinued work on it.

Source:  http://www1.eere.energy.gov/solar/solar_time_1767-1800.html, http://www1.eere.energy.gov/solar/solar_time_1900.html, and http://www1.eere.energy.gov/solar/solar_time_2000.html

 As you can see, once the potential for getting electricity directly from sunlight became plain, the technology has been growing leaps and bounds.  Thermal applications are still in play, but the Holy Grail for solar electrical production has been mass production of PV cells which are cost effective and efficient enough to begin allowing wide scale adoption by homeowners.   Once that is possible, the move away from our almost complete reliance on fossil fuels can begin in earnest. 

 
But developments in the field of solar energy have not been purely about getting more electricity out of increasingly exotic materials.  Scientists and engineers around the world have been pursuing two overall approaches to get the most from our sun: passive and active. 

Take care,

 Sullivan