small solar electric system installation and maintenance
Proper installation and maintenance of a small
solar electric or photovoltaic (PV) system is essential for maximizing
its energy performance. [Note: This article is written specifically to advise
US consumers but its main points apply generally.]
When installing a PV system, important factors to consider are:
It is generally best to have a professional solar contractor install the
When choosing a contractor, the following questions should be asked:
It is always a good idea to get more than one bid for the installation of
your PV system. Make sure that all bids are made on the same basis. For
example, a bid for a system mounted on the ground is usually very different
from another bid for a rooftop system.
- Has the company installed grid-connected PV systems? If not,
has it installed grid-independent (or stand-alone) PV systems?
Experience in installing grid-connected
systems is valuable because some elements of the installation –
particularly interconnection with the local utility – are unique
to these systems. However, a competent company with off-grid PV experience
should not be eliminated just because it has not yet installed grid-connected
PV systems. Experience with off-grid
systems is valuable too, because grid-independent systems are more
technically complex than grid-tied systems.
- How many years of experience does the company have installing
A contractor who has been in business a long time probably understands
how to work with customers and to compete effectively with other firms.
Additionally, he/she will probably be aware of the latest code
and permitting issues surrounding the installation of PV systems.
- Is the company properly licensed or certified?
PV systems should be installed by an appropriately licensed contractor.
This usually means that either the installer or a subcontractor has
an electrical contractor's license. Your state electrical board can
tell you whether a contractor has a valid electrician's license. Local
building departments might also require that the installer have a general
contractor's license. Call the city or county where you live for additional
information on licensing. A solar rebate program may require that, in
addition to being properly licensed, installers must demonstrate that
they have special knowledge about installing PV systems. Special knowledge
can be demonstrated through certification by solar industry and/or trade
- Does the company have any pending or active judgments or
liens against it?
As with any project that requires a contractor, due diligence is recommended.
Your state electrical board can tell you about any judgments or complaints
against a state-licensed electrician. Consumers should call the city
and county where they live for information on how to evaluate contractors.
The Better Business Bureau is another source of information.
Similarly, some solar modules generate
more electricity per square foot than others. Bids should clearly state
the maximum generating capacity of the system – measured in watts
(W) or kilowatts (kW). If possible, have the bids specify the system capacity
in "AC watts" (alternating current) under a standard set of test conditions,
or specify the output of the system at the inverter. Also request an estimate
of the amount of energy that the system will produce on an annual basis
(measured in kilowatt-hours).
Because the amount of energy depends on the amount of sunlight – which
varies by location, season, and year to year – it's unlikely the contractor
will quote a specific figure, but a range of 20% is realistic. Bids also
should include the total cost of getting the PV system up and running, including
hardware, installation, connection to the grid, permitting, sales tax, and
Your warranty is also a very important factor for evaluating bids. A solar
rebate program may require that systems be covered by a two-year parts-and-labor
written installation warranty, for example, in addition to any manufacturers'
warranties on specific components (including inverter and module warranties).
The installer may offer longer warranties. Also ask yourself, "Will this
company stand behind the full-system warranty for the next two years?"
As with any mechanical or electrical appliance, PV systems require routine,
periodic maintenance. System
components may also need repair or replacement from time to time.
An efficient and long-lasting system will depend on a periodic check of
system components and completion of any preventive maintenance as necessary.
Talk with your system installer about routine and periodic maintenance.
In the event of a system malfunction, effective troubleshooting and repair
You may be able to carry out many routine inspections and maintenance tasks
yourself. If, however, you are not the do-it-yourself type, or if there
is a major problem with your system, you will need to locate a professional
to do the work.
ENERGY AND POWER