The PVWATTS site is used to calculate estimated system production from a solar system.

Once the PVWATTS site is accessed there are two versions available for analyzing solar grid tied system production. Version 1 is simpler to use and is typically adequate for system evaluation. Version 2 is more accurate, but is significantly more difficult to use and is not recommended.

To use PVWATTS perform the following:

• Start on this site. 
• Select Version 1.
• Again scroll down the page and select "PVWatts Version 1 Calculator" (second bullet). You will see the map, click on New Jersey, or select the link for an alphabetical list of states and select New Jersey.
• From the map of New Jersey select either Newark or Atlantic City whichever is closer. If you cannot decide which is closer to your location a rule of thumb is the further south the better the production numbers.

Input the following information:

• The proposed system size in kW-DC.
• Leave the standard derate factor at .77.
• From the drop down menu select the array type.
• If you system is fixed tilt or single axis tracking then input the tilt angle.
• Input the compass heading of the major portion of the system in degrees.
• Enter the local cost of electricity or leave it at the default value of 11.2 cents per kWh.

Select the calculate button.

View and print out the results page.