The Birth of a Technology French scientist
Edmund Becquerel in 1839 discovered the photovoltaic effect – that
light falling on certain materials can produce electricity.
Later physicist, including Albert Einstein, found that tiny
photons, or particles of light, could interact with electrons
surrounding the nucleus of an atom. That interaction causes a free stream of electrons - the
basis of electricity. Scientists in the 1930s
developed a theory for the electrical properties of silicon and
other crystalline materials, substances that came to be known as
“semi-conductors.” Primitive
photovoltaic cells were developed using selenium, but they were very
expensive, only one percent efficient, and little more than a
scientific curiosity. Early in 1954, a small team of
scientists at Bell Laboratories tried to find a practical way to
generate electricity for telephone systems in rural areas not
connected to power lines. Using
crystalline silicon, they fashioned an enormous solar cell capable
of turning six percent of the sunlight that struck it into
electricity. Soon the
efficiency was raised to eleven percent and scientists realized that
the new devices could have practical applications. They had another
reason for optimism; the material they were using, silicon, is the
world’s second most abundant element, comprising 28 percent of the
earth’s crust. These achievements were greeted
with much fanfare amid the technological developments of the 1950s.
Solar cells seemed to promise an unlimited supply of
electricity and roused considerable excitement.
A 1957 article in “Business Week” envisioned an
automatically controlled solar car in which “all riders could sit
comfortably in the back seat and perhaps watch solar-powered TV.” It was an unfavorable time,
however, to develop a new energy technology.
Oil was priced at less than $2 per barrel, and large
fossil-fuel power plants were built at a record pace.
Moreover, in 1954 construction began on the world’s first
commercial nuclear reactor. Nuclear
power was envisioned as a source of electricity “too cheap to
meter,” and most government energy funds were devoted to that
technology. Photovoltaic researchers also faced an unsettling economic reality. Silicon cells developed in the 1950s were extremely expensive, with costs as high as $600 per watt (compared to $5 or $6 today). Funding for research to reduce the cost was not available in an era with falling electricity prices and minimal concerns about the environment. The space program rescued
photovoltaics from the technological scrap heap.
American scientists in the late 1950s went searching for a
lightweight, long-lasting power source for satellites.
Photovoltaic cells, which could take advantage of the
continuous sunlight of space, were their choice. In 1958 just four
years after the Bell laboratory breakthrough, silicon solar cells
were boosted into orbit aboard Vangard I, the second U.S. Satellite. With the help of large contracts
from the National Aeronautics (NASA) four U.S. commercial companies
enter the photovoltaics business and by the late 1960’s were
producing hundreds of thousands of solar cells a year.
Amid the heady competition of the post-sputnik space race,
the Soviet Union began equipping its satellites with photovoltaics
as well. Today, solar
cells power virtually all satellites. Achievements in photovoltaic
cell research during the peak years of the space program included a
major increase in efficiency and reduction in cost of more than 400
percent. However, the
space-related PV market leveled-off and photovoltaic cell production
declined. In 1973, America was jolted by
its first oil crisis – gasoline prices soared and interest in
alternative fuels was awakened.
Beginning in 1975, the U.S. government funded a steadily
growing research and development program aimed at making
photovoltaics economical for terrestrial use.
Japan and European countries followed suit. Perhaps a dozen private companies entered the solar cell
research or production business. Since the 1970s, the overall
market for photovoltaics has increased more than ten-fold.
In the same period, the cost of PV modules has dropped from
about $50 per watt to $5 or $6 per watt.
Production has increased to more than 250 times the highest
level during the peak years of the space program, and can barely
keep up with demand. |
