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Solar energy is a renewable energy source, often categorized as
"green" energy along with wind, biomass, hydrogen and
geothermal energy. Renewable energy resources are constantly replenished,
in contrast to fossil fuels like coal, oil and natural gas. We must
find ways to use renewable energy because our fossil fuel resources
will start to run out between 2020 and 2060, according to analysts
of the fuel industry.
Renewable
energy is a cleaner source of energy than conventional energy technologies.
Fossil fuels create many of the world's environmental problems—air
pollution, greenhouse gases, and water/ soil contamination. Renewable
energy causes little or none of these problems. For example, solar
energy produces heat and electricity without the carbon dioxide
emissions that contribute to global warming.
Photovoltaics,
the method by which sunlight is converted into electricity, is a
word derived by combining the Greek word photos (light) with
voltaic (after Alessandro Volta, a pioneer in the study of
electricity). A solar photovoltaic (PV) cell is one that converts
sunlight (not sun heat) into electricity. PV cells are made of a
semiconductor material like silicon. When sunlight hits the panel,
an electrical current is formed. Usually an inverter will convert
this DC (direct) current into AC (alternating) current, the type
of electrical current used by households and businesses.
Grid-tied
PV systems are becoming popular. These PV systems are wired into
buildings already connected to the utility grid. Energy produced
by a PV system can be used directly in your home or business, or
flow out through your meter if there is excess, providing power
to your neighbors. You can potentially receive a credit for this
excess power, e.g., at night, when you need more power from the
grid.
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A
History of Solar Energy
After making its commercial debut in solar-powered toys and
games, solar energy was used in the sixties and seventies to
power satellites in the space program. Solar energy was a more
functional and efficient source of energy than batteries that
burned out within a week of orbit. Solar cells are now used
"terrestrially" as well, in water pumps and for home
heating. Coast Guard navigation devices and many developing
modes of transportation are turning to solar power as their
energy source.
The U.S. government began to fund solar power programs in the
mid-seventies and eighties, but the power plants were large
and centralized. Gradually it became clear that by installing
rooftop solar cells, individual homes could be self-sufficient
solar power plants.
Solar energy has only recently become a practical energy alternative.
With a huge per-watt-cost of $300, solar energy far exceeds
the $0.50 per watt cost of power from a conventional power plant.
Recent technical innovations, however, have increased efficiency
and reduced costs.In addition, both short- and long-term incentives—governmental
rebates and local power company buybacks—make solar power
an increasingly worthwhile investment. |
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