The Size or Capacity of your NEM Generating System

The size or capacity of your generating system is an important issue for Net Energy Metering applicants. All the Net Energy Metering programs require generating systems to be no more than 1,000 kilowatts (kW) in size to qualify. The size of your system may also determine which program you are eligible for.

If your generating system does not have inverters:

The manufacturer of your system should give a rating (usually stamped on the system’s nameplate) in kW. The rating in kW will be the size of your system.

If your system has inverters:

There are two steps for figuring your system size.

Step 1:

Total the manufacturer’s listed rating of each inverter times the inverter’s efficiency rating as listed on the CEC equipment listing. For example if your system has two inverters, one rated 2.5 kW with a 95% efficiency rating and the other rated 3.5 with a 98% efficiency rating, the size of your system would be: (2.5 x .96) + (3.5 x .98) = 5.83 kW.

Step 2:

Total the ratings of all the generators (such as photovoltaic modules) connected to the inverters.

The size of your system is equal to the smaller of the two results from these steps.