Hundreds of 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 facilities.

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 

Unlike the 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 ?

No, you remain connected to the power company, but instead of only using the energy that the power company produces, your facility actually becomes an independent power producer. Or in essence its own power company ! 

Solar 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 one !

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 you produce.

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.