Photo Voltaic Solar Panels
Basic Information About Residential PV Systems
How does solar produce electricity?Why
should I buy a PV system?
There are excellent reasons to invest in a PV system: A PV system is
cost-effective and produces clean, reliable energy that reduces the
load on the
utility grid. With a PV system, you will decrease or eliminate the
amount of
electricity you buy from the power company, and provide a hedge against
future
price increases. Often, the cost to finance a PV system is less than
the cost
of the power it will offset. The equipment will last for many years, is
relatively low-maintenance, and will appreciate the value of your
property --
without increasing your property taxes.
Will
a grid-tied system work
during power outages?
Due to safety regulations, a grid-tied PV system will automatically
shut down
during power outages. If continued power is essential, you can invest
in an
uninterruptible power supply (UPS) or generator. Grid-tied systems with
battery
backup are also available, although they will increase the installation
costs,
maintenance and toxicity, and decrease performance efficiency. Fuel
cells are a
more appealing technology for storing power, but are not yet widely
available
or cost-effective.
Is
my home a good site for a
PV system?
A site is most suitable for a PV system if there is clear and
unobstructed
access to the sun for at least six hours during the middle of the day.
Shading
from trees, buildings or other vegetation will compromise the
performance of a
PV system. Usually, the most ideal site is a large roof area with good
southern
exposure, although other orientations may also work. If the roof is not
suitable, a PV system may be mounted on the ground. Although the cost
may be
higher, it will be a good tradeoff if there is an increase in the
amount of
sunlight available for the PV system.
How
many PV panels will I
need?
The number of PV panels needed depends on your electricity demands and
system
design. If you have energy efficient appliances and a relatively
“energy
conservative” lifestyle, it’s possible to meet up to 100% of your
electricity
needs with a 2.5 kilowatt grid-tied system. Such a system typically
uses 18-20
PV panels. If the PV system design includes battery backup, you will
need about
20% more panels to provide the same amount of energy.
How
much area will my PV
array need?
Plan on one square foot of roof or ground area for each 10 watts of
power, or
100 square feet per kilowatt. For example, a 2.5-kilowatt system will
require
approximately 250 square feet of space.
Where
will the PV panels be
mounted?
Usually, PV panels are placed on an existing roof, using an aluminum
mounting
structure. If the roof is not suitable, PV panels can be mounted on the
ground,
using a freestanding support structure. Pole mounts are often used for
smaller
arrays, such as those used for well or pond pumping systems, but not
for larger
grid-tied systems.
How
long will my PV system
last?
Most PV panels carry a 25-year limited warranty. Although panels have a
useful
life expectancy of more than 40 years, it is normal for panels to
slowly
degrade as they age, causing some decrease in output. Inverters, like
other
complex electronic components, have a limited life span and most likely
will
need to be replaced within 12-to-15 years. Look for a 5-year warranty
on
inverters and all other materials and labor, to assure that you won’t
have
additional costs during this phase of the system’s life. Even with the
cost of
service and repairs, which are very minimal, the systems are very
reliable and
cost effective.
How
long will the
installation take?
The installation of a PV system usually takes up to five days,
depending on the
size and scale of the job. However, the entire process generally takes
several
weeks, due to the lengthy and detailed process of filing for the
interconnection
agreement.
What
other issues may need to
be considered?
It is a good idea to find out about: (1) Required approval from a
homeowners’
association, including covenants, conditions, and restrictions (CCR’s)
that may
exist; (2) Permit problems or illegal structures or issues you
anticipate if a
building inspector visits the property; (3) Roof condition, including
need for
(and cost of) repair or replacement before installation; (4) Need for
(and cost
of) removing trees or other vegetation that may shade the PV system
area; and (5)
The likelihood of your PV system’s visibility raising any issues with
neighbors.
