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.