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How Solar
Power Works
There are many different types of solar power applications
ranging from a few cells powering a calculator to large utility-grade
plants generating megawatts of electricity to power hundreds
of homes. Photovoltaic (PV) systems can be configured to suit
a wide range of applications. A typical home installation
works as follows:
- Rays of light from the sun strike the solar panels and
are absorbed. The panels are made from a special type of
silicon that converts solar energy into DC electricity.
- The DC electricity from the solar panels enters the inverter.
The inverter converts it into AC electricity, which is the
type used in a typical home.
- The utility panel in the house receives the AC power
from the inverter and distributes it to the loads (e.g.,
lights, appliances, etc.). If the solar panels are not generating
enough electricity to satisfy the house loads (for instance
at night), the utility panel will draw additional electricity
from the grid.
- If the solar panels are generating more electricity than
is being used in the house, the inverter will convert some
of the DC electricity from the panels to the appropriate
DC voltage required to charge the batteries.
- If the batteries are fully charged and the solar panels
continue to generate more electricity than is required by
the house, the excess is exported to the utility grid.
- The utility meter measures the electricity flowing in
and out, spinning forward and backward as appropriate. You
only pay for the difference between the amount of energy
used and the amount of energy exported. This is called “net-metering.”
(Click here to see if
net-metering is allowed in your state.)
- If power from the grid is not available (such as during
a blackout), a battery backup inverter switches over to
battery power. Critical loads in the house will continue
to have power supplied to them from the batteries, for as
long as they are sized to provide it.
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