How Solar Cells Work
Solar cells power many things from calculators to entire businesses.
While small cells have been powering things such as calculators
for many years, it has not been until recently that large cells
have begun to power entire homes. They can also be used to light
billboards and as power for street lights even after the sun has gone
down. They're a great source of energy because of their low environmental
impact, their durability and limited maintenance needs, and their
cost-effectiveness over time.
Large cells, also known as photovoltaic cells, used to power
homes, are single cells grouped together and electrically connected
and packaged in a frame. These cells work by converting sunlight into
electricity using semiconductors that absorb sunlight and create
electricity through the transfer of electrons.
Silicon is the most commonly used semiconductor in solar cells.
When sunlight hits the cell, the light is absorbed by the
semiconductor material and the energy contained in the absorbed
light is transferred through the semiconductor and turned into
energy. The cells create a flow of electrons, or electrical
current, by using electric fields to force electrons absorbed
through sunlight to flow in one direction. Contacts placed on
the top and bottom of the cell allow us to draw the electrical
current off of the cell and use it to power our homes or
There are many advantages to using solar cells to power a
home and other electrical items. Solar power
is non-polluting, quiet, and very cost effective after the initial investment
has been recapped through energy savings. Because they
last for many years, users will be able to continue to draw
electricity from them long after they have paid for themselves.
One drawback to solar power is its efficiency. Until
it becomes more efficient, many homeowners may find the initial
investment too costly since so many cells are needed to generate
enough electricity to power their home. For cost savings, you could
build your own solar panel
rather than having to buy them.
Most cells are only about 40% efficient which means that they only
convert about 40% of the light that hits them into electricity. This
means that to create enough electricity to power a home, many cells
are required - a large investment, perhaps "too large" for
many homeowners to manage. As technology improves so too does the
efficiency. With a dramatic improvement in efficiency,
solar home heating will
likely become more attractive.
Another common issue with solar cells is the lack of power
when sunlight is not available. At night and on cloudy days very
little sunlight is available to convert into energy. This problem
can be alleviated by using batteries to store extra energy produced
during the day although batteries do not have the life expectancy
of solar cells and have to be replaced more frequently.