government agencies throughout the U.S. whose budgets were
being consumed by of the
high cost of electricity have taken advantage of generous cash
rebates which are available for the
installation of solar electric systems on their their
For example, the
State of California is currently offering a cash rebate of
$4000.00 per kilowatt of installed solar power ! Many other state are participating in similar
programs. Click here to
find out whether or not your state offers a rebate program
old solar systems of yesteryear that only produced hot water,
these new systems actually produce electricity ! Clean
reliable electricity to run lights, air conditioning,
computers, lighting and many other types of equipment, all with free energy from
the Sun !
Do we have to
disconnect from the electric company ?
you remain connected to the power company, but instead of only
using the energy that the power company produces, your
becomes an independent power producer. Or in essence its own
power company !
electric systems has just about reached plug and play
simplicity. There are no moving parts to break, no critical
monitoring and virtually no noise. Solar modules simply sit in
the Sun and generate electricity, year in and year out, in
fact, the typical solar module carries a warranty of 25 years
and in most cases are expected to last double that amount of
time making your facility's investment in solar an equitable
above is a graphic which
illustrates the basic configuration of a typical solar
electric system. The Solar PV Array or Photovoltaic Array on
the left is the actual energy collecting unit, it may be
mounted on the ground, on a a roof top or on a pole as
illustrated. The array should be pointed due South and tilted
so that there is maximum exposure to the Sun.
The energy which is collected
is then fed through wires in the form of DC or direct current
to the energy conversion unit, typically called an inverter,
where the direct current is "inverted" to AC or
alternating current. This is the type of current which is
found in your home's AC outlets.
The inverter synchronizes the
AC current that it produces with the utility companies AC
current and then feeds that current through your utility meter
and on to the grid. Because you are producing power, your
utility meter will actually slow down and in many cases will
actually run backwards. If you are in a "Net Metering
State" such as California, your utility company is
required to credit you full retail price for the power that
Will we need batteries for our system ?
The choice of whether or not
to use batteries is a individualized issue and there are
tradeoffs involved . Both battery-less and battery backed up
solar electric systems will perform grid intertie, meaning
that they both will sell the surplus power that you produce
back to your utility company, although there are efficiency
differences when comparing both systems.
It is mainly during a utility power failure that the difference becomes obvious. With a battery-less system, should there be a power failure, the system is designed to automatically shut down. Your
facility will not have electricity available until the utility company has restored their power.
The reason for this is a matter of safety. If the power has failed and the utility company has sent a lineman up a pole to implement repairs, the last thing you want to do is feed power down the line when the lineman thinks that the power has been cut. This is why the system has been designed to make it impossible to operate the inverter when there has been a power failure.
The battery backed up system utilizes a completely different design. Like the battery-less inverter, as long as the utility company's system is operating normally, your
facility's solar system will feed power through you meter providing
it with a reduction in it's electric bill.
In the event of a power failure the battery backed up system will also stop feeding power to the utility company for the same reasons mentioned above,
but unlike the battery-less system, this system will divert
backup power to your facility.
Depending on the size of the battery pack that you choose you can supply your
facility with power for several hours or even days.
When the power company restores power, your system will automatically begin selling power back to the grid. Note : Because batteries are involved in a backup type system, the overall power production efficiency of a battery backed up system
will be less than that of an equally sized battery-less system.
The decision to choose a battery-less or battery backed up system mainly boils down
to the following issues: Does your facility need back up power during a power failure ?
Is your agency willing to sacrifice efficiency, which means less
payback from the utility company and is it in your agency's
budget to maintain the additional expense of replacing the battery pack every 5
to 6 years.
How do I determine what size solar system we'll need ?
Although the following method
is not as accurate as calling your utility company, you can
approximate this number if you have a few copies of your
electric bill. What you will need is a copy of your bill which
represents your average Winter usage lets say January as well
as your average Summer usage, lets say July. Add the two bills
together and then divide the sum by two. For example if your
Winter monthly usage is typically 600 Kwh and your Summer
usage is typically 1000 Kwh then your average monthly Kwh
would be approximately 800 Kwh.
Next we will need to
determine your average daily usage. This is simply done by
taking the average monthly Kwh number and divide it by 30
days. In the above example 800 Kwh per month divided by 30
days equals 26.67 Kwh per day. This is how much power your
system will need to produce per day in order to approximately
eliminate you electric bill.
Next we must take the daily
Kwh number and divide it by the average number hours of full
sunlight that is available to you on a daily basis. In
California for instance, that number is approximately 5 hours.
There is obviously more sunlight available during an average
day especially in California, but what we're concerned with
here is FULL sunlight.
So in our above example 26.67
Kwh or 26,670 watt hours, ( Remember Kilo means One Thousand )
divided by 5 hours equals 5.33 Kwh or 5,334 Watt hours.
Finally we will need to
factor in the size of the solar module that we are using and
we'll know how many modules we'll need to approximately
eliminate the above mentioned electric bill.
A typical sized module used
in this type of system has a PTC adjusted rating of 103.9
watts. So we would take the 5,334 Watt hours mentioned in the
above calculation and divide that number by 103.9 watts per
module and we get 51.338 modules. There is no such thing as
.338 of a module so we will need to round up to 52 modules.
The above example would apply
if you wanted to eliminate your bill, cut it in half or
eliminate what ever increment you wanted from your bill.
Simply take the number of modules that you would need to
approximately eliminate your bill and multiply that number by
.75 to approximately reduce your bill by three quarters, .50
to approximately reduce it by half or .25 to approximately
reduce it by one quarter.
The above calculations may
seem a bit daunting but don't worry, that's what our staff is
here for. We're experts at helping you to choose the perfect
system for your needs, whether that is to reduce your
facility's bill by
10% or eliminate it entirely. We offer free design services
and accept government Purchase orders. Just give us a call
we're here to help 1-888-955-3471