The computer performance approach allows for the modeling of the battery storage system performance by taking into account battery system size, climate, building type, and battery efficiency. The standard design battery storage system size is determined by the prescriptive PV size required for proposed design building, regardless of the actual fuel type of the proposed design building. The performance method allows for battery storage system, control strategies and other demand-response measures.

The five allowable exceptions to the prescriptive PV requirements listed in Section 9.6.2. can also be used under the performance approach. User must select the appropriate exception in the software and provide documentation to the building department with the building permit application.

The installed battery storage system must meet the applicable requirements as specified in JA12, above.