History of Solar

From ancient Greek homes built to face the warm winter sun to advanced thin-film photovoltaics, which generate electricity from the sun, humans have used the sun’s rays to meet their energy needs. This makes sense, given that the sun showers the earth every hour with enough energy to meet world demand for a year. And the best part: this energy is pollution-free, inexhaustible and accessible to many.

A Brief History of Solar Energy

Ancient Greeks and Romans saw great benefit in what we now refer to as passive solar design—the use of architecture to make use of the sun’s capacity to light and heat indoor spaces. The Greek philosopher Socrates wrote, “In houses that look toward the south, the sun penetrates the portico in winter.” Romans advanced the art by covering south facing building openings with glass or mica to hold in the heat of the winter sun. Through calculated use of the sun’s energy, Greeks and Romans offset the need to burn wood that was often in short supply.

Auguste Mouchout, inventor of the first active solar motor, questioned the widespread belief that the fossil fuels powering the Industrial Revolution in the 19th century would never run out. “Eventually industry will no longer find in Europe the resources to satisfy its prodigious expansion. Coal will undoubtedly be used up. What will industry do then?” Mouchout asked prophetically.

In 1861, Mouchout developed a steam engine powered entirely by the sun. But its high costs coupled with the falling price of English coal doomed his invention to become a footnote in energy history.

Nevertheless, solar energy continued to intrigue and attract European scientists through the 19th century. Scientists developed large cone-shaped collectors that could boil ammonia to perform work like locomotion and refrigeration. France and England briefly hoped that solar energy could power their growing operations in the sunny colonies of Africa and East Asia.

In the United States, Swedish-born John Ericsson led efforts to harness solar power. He designed the “parabolic trough collector,” a technology which functions more than a hundred years later on the same basic design. Ericsson is best known for having conceived the USS Monitor, the armored ship integral to the U.S. Civil War.

Solar power could boast few major gains through the first half of the 20th century, though interest in a solar-powered civilization never completely disappeared. In fact, Albert Einstein was awarded the 1921 Nobel Prize in physics for his research on the photoelectric effect—a phenomenon central to the generation of electricity through solar cells.

Some 50 years prior, William Grylls Adams had discovered that when light was shined upon selenium, the material shed electrons, thereby creating electricity.

In 1953, Bell Laboratories (now AT&T labs) scientists Gerald Pearson, Daryl Chapin and Calvin Fuller developed the first silicon solar cell capable of generating a measurable electric current. The New York Times reported the discovery as “the beginning of a new era, leading eventually to the realization of harnessing the almost limitless energy of the sun for the uses of civilization.”

In 1956, solar photovoltaic (PV) cells were far from economically practical. Electricity from solar cells ran about $300 per watt. (For comparison, current market rates for a watt of solar PV hover around $5.) The “Space Race” of the 1950s and 60s gave modest opportunity for progress in solar, as satellites and crafts used solar paneling for electricity.

It was not until October 17, 1973 that solar leapt to prominence in energy research. The Arab Oil Embargo demonstrated the degree to which the Western economy depended upon a cheap and reliable flow of oil. As oil prices nearly doubled over night, leaders became desperate to find a means of reducing this dependence. In addition to increasing automobile fuel economy standards and diversifying energy sources, the U.S. government invested heavily in the solar electric cell that Bell Laboratories had produced with such promise in 1953.

The hope in the 1970s was that through massive investment in subsidies and research, solar photovoltaic costs could drop precipitously and eventually become competitive with fossil fuels.

By the 1990s, the reality was that costs of solar energy had dropped as predicted, but costs of fossil fuels had also dropped—solar was competing with a falling baseline.

However, huge PV market growth in Japan and Germany from the 1990s to the present has reenergized the solar industry. In 2002 Japan installed 25,000 solar rooftops. Such large PV orders are creating economies of scale, thus steadily lowering costs. The PV market is currently growing at a blistering 30 percent per year, with the promise of continually decreasing costs. Meanwhile, solar thermal water heating is an increasingly cost-effective means of lowering gas and electricity demand.

As you’ve seen, technologies have changed and improved for decades. Still, the basics of solar thermal and photovoltaics have remained the same.

	How PV and solar thermal works
	Solar in the Southeast
Sources:
	www.solarenergy.com/info_history.html
	www.californiasolarcenter.org/history_pv.html
	“Winner, Loser or Innocent Victim?” Discussion Paper 99-28. Resources for the Future.
	“OECD Total Gross Oil Imports from OPEC, 1991-2003.” Energy Information Administration.