Photovoltaics
As the world searches for alternatives to fossil fuel energy, solar power is
emerging as one of the cleanest and most reliable renewable energy sources.
Money spent on research and development is producing more efficient and
affordable photovoltaics that have a broader range of use.
Photovoltaics are often referred to as solar cells, and they are capable of
converting light into electricity. They have been used on small devices like
calculators and watches for many years, but they are also capable of producing
enough electricity for a house or industrial complex.
The first photovoltaic cells were produced in the 1950s and found use in the
space program powering satellites. Over the next several decades the technology
was refined and production costs came down. During the 1980s solar cells began
to find use as a means to provide electricity to remote areas that would
otherwise be impractical to connect to existing power grids.
Today photovoltaic's can be used in conjunction with power from utility
companies. Houses or factories that have solar panels installed can use solar
power during the daylight hours and draw power from the utility company at
night. This reduces electrical bills and also reduces the amount of power which
must be produced by the utilities.
Photovoltaic cells are made of thin layers of silicon which have been treated to
create an electrical field when they are exposed to sunlight. Each cell produces
about 0.5 volts, so they are connected together in modules and arrays to produce
usable amounts of electricity. They can be wired in parallel or in series to
provide almost any combination of voltage, wattage, and power levels.
Electricity produced by photovoltaic's is Direct Current (DC). In order to be
used by most household appliances it must be convert to Alternating Current
(AC).
When photovoltaic arrays are connected to the power meter of a utility company
they are used to reduce the amount of power drawn from the utility. This called
"Net Metering" If the solar cells produce more electricity than is consumed by
the household, the excess will pass to the electrical grid, causing the meter to
reverse and giving a credit to the homeowner.
The downside to this sort of systems is that they still are pretty expensive. An
other concern is that the production of a panel will cost approx. the energy the
cell is going to produce in six to eight years. Still one more challenge is
emerging on the horizon, namely the scarcity of silicum, the base material for
solar or pv panels.
Photovoltaic systems are by no means dead, and are really an addition to our
arsenal of alternative energy solutions, but there are problems.
I have 8 110Wp Power Panels on my roof and because we try to get our energy
consumption down with measures that doesn't really have a huge impact on our
lives (turn the TV of, have no heaters or airco's running while your not there,
read the energy ratings of products) we are able to produce about 15% - 20% of
our needs from the sun.
Our solar boiler takes care of 10% and our wind turbine is doing not so well at
the moment but still add about 5%. I have to work on the latter. We live in a
windy area but somehow I can't get the turbine running to its capacity. I'll
keep you posted
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