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How Efficient is Solar Energy? Factors that Affect Efficiency
Understanding how solar efficiency is measured helps to determine
if you are getting the most from your system. Efficiency can be
measured by the number of kWh (kilowatt-hours) of energy produced
an "average" 150 watt solar panel of one square meter in
size. How efficient
is solar energy, and is it a viable option for homeowners?
The average solar cell efficiency is thought to be between 12%
and 15%. The efficiency is dependent on many factors: how much
sunlight it gets; the angle of the solar panels; whether parts
of the cell are shaded; and how clean the solar panels are.
Solar panel installations may produce only 1 kWh/m2/day,
or they might produce as much as 8 kWh/m2/day or higher.
Keeping panels clean and free of dust and debris can help them
to better absorb sunlight and produce more output. Likewise, you
can help your solar panels by locating them in sunny areas that
aren't shaded by trees, parked cars, buildings or other structures,
since even a little bit of shading can dramatically decrease the
cell's output. You will also need to tilt your panels to get the
best exposure to the sun. Most homeowners just mount the panels
in a fixed position, but there is a device known as a solar tracker
that re-orients your solar panels as the sun moves across the sky.
They add to the cost of a system, of course -- and they need to be
properly maintained -- but they also help solar
cells maximize output.
Many people are under the misconception that
solar power is totally cost-free.
Yes, the sun is free but the energy produced by a photovoltaic
system is not. It's not uncommon for a system to cost tens of
thousands of dollars. The significant initial investment is a big
reason that solar power is primarily being used in remote areas that
do not have access to traditional power companies. Over time, a solar
powered system can pay for itself, however the initial price tag
presents a steep hurdle for many homeowners. Optionally, and for a
much smaller investment, homeowners could decide to use solar energy
selectively within the home - for instance, the use of solar
water heating - or if you're the handy type, you might decide
to build your own solar
panel for additional cost savings. On the positive side, solar
panels often last 25 years or more.
Research is ongoing with strong beliefs that solar power will
be cost-effective in the near future, but also competitive with
traditional power companies and more widely used in urban areas.
In 2007, a team lead by the University of Delaware, produced a
record-breaking solar cell efficiency of 42.8% (the previous
record was 40.7% efficiency). As solar cell efficiency continues
to improve, look for solar power to become a much more attractive
and cost-effective energy alternative for both homeowners and