California is the first state to require solar power plus energy storage to be integrated into all future commercial structures via its most recent update to building codes. All new residential construction must also be ready for the addition of energy storage.

The requirements approved by the California Energy Commission in the 2022 Building Energy Efficiency Standards are projected to add 280 MW of annual solar capacity as well as 400 MWh of energy storage in the state. The solar energy systems should be sized to meet a target of 60% of the structure’s loads, and the target energy storage component should be sized to reduce electricity exports to 10% of the total solar generation. The batteries must have a usable capacity of at least 5 kWh, a round trip efficiency of greater than 80% and greater than 70% nameplate capacity remaining after 10 years or 4,000 cycles.

New residential construction must also be battery ready, and new homes are required to install a 225 A busbar, four backed-up circuits (two of which must be the refrigerator and bedroom receptacle outlet), and a subpanel or a split-bus main panel for those circuits.

The code requires battery systems to be capable of remote programming, enabling distributed energy storage to harmonize with the power grid. Under basic control mode dictates that by default, the battery must be able to charge from a solar photovoltaic system. Batteries must also be programmed to charge only by solar electricity and discharge during the highest priced time of use hours of the day. With advanced demand response flexibility control, storage systems can alter the charge and discharge periods in response to signals from the local utility or a third-party aggregator.

In the next 30 years, the 2022 Energy Code is estimated to provide $1.5 billion in consumer benefits and reduce 10 million metric tons of greenhouse gases, equivalent to taking nearly 2.2 million cars off the road for a year.

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