The 2022 Building Energy Efficiency Standards (Energy Code) has battery storage system requirements for newly constructed high-rise multifamily buildings that require a solar photovoltaic (solar PV) system (2022 High-rise Multifamily Solar PV Fact Sheet).
The solar PV requirements apply to buildings where at least 80 percent of the total floor area (conditioned or not) is made up of building types specified in Table 170.2-V, including mixed occupancy buildings. These building types include:
- High-rise multifamily
- Office, financial institutions, unleased tenant space
- Auditorium, convention center, hotel/motel, library, medical office building/clinic, restaurant, theater
These requirements do not apply to additions and alterations.
The required battery storage system size is based on the solar PV system size determined for building types listed in Table 170.2-V, including mixed-occupancy buildings.
Section 170.2(h) of the 2022 Energy Code has two equations to calculate the total battery capacity for building types listed in Table 170.2-V using the solar PV system size calculated from Equation 170.2-D.
- Rated energy capacity (Equation 170.2-E), based on:
- Required solar PV system size
- Energy capacity factor
- Round trip efficiency of the battery system
- Rated power capacity (Equation 170.2-F), based on:
- Required solar PV system size
- Power capacity factor
The total capacities of a battery storage system shall not be less than those calculated from the equations above. For mixed use buildings that contain the building types listed in Table 170.2-V, the capacities should be determined for each building type, including its support areas, then added together for the entire mixed use building.
The standard design battery storage system size is determined using the prescriptive solar PV size requirement for the proposed design, regardless of the fuel type. A battery storage system can be installed as a standalone system for additional compliance credit, when not required prescriptively. Also, a battery system larger than the prescriptive requirement can be used to tradeoff for a smaller solar PV system.
Yes. Two exceptions can exclude high-rise multifamily buildings from the battery storage system requirements:
- If the installed solar PV system size is < 15 percent of the size calculated from Equation 170.2-D
- Buildings with battery storage system requirements < 10 kWh rated capacity
NOTE: The solar PV requirements still apply when exempted from battery storage.
The installed battery must meet or exceed requirements in the 2022 Reference Joint Appendix JA12 and be manufacturer-certified to the California Energy Commission (CEC). A list of certified batteries is available on the CEC website.
The battery storage system must meet the minimum system performance requirements specified in Table 1 below, in addition to the following requirements:
- Control strategies,
- Interconnection and Net Energy Metering, and
- Verification of Certificate of Installations by the local enforcement agency
Table 1: Minimum Performance Requirements for Battery Storage Systems
|Battery Performance Specification
|Usable capacity > 5kWh
|Single charge-discharge cycle AC to AC (round-trip) efficiency > 80%
|Energy capacity of 70% of nameplate capacity after 4,000 cycles
covered by warranty or 70% of nameplate capacity under 10-year warranty.