Combining battery energy storage with solar photovoltaic (PV) systems would lead to significant electric bill savings for both property owners and residents of multifamily affordable rental housing in California, according to a new report from the California Housing Partnership, Center for Sustainable Energy and Clean Energy Group.
The authors say the report findings are particularly important given the 2015 passage of A.B.693, which established the state’s Multifamily Affordable Housing Solar Roofs program and provides up to $1 billion in cap-and-trade funding over 10 years to create incentives for installing solar PV systems starting in 2017.
Key findings of the report include the following:
– Under current utility rate tariffs, the combination of solar and battery storage technologies could virtually eliminate electric bills for some owners of affordable rental housing. Unlike stand-alone solar, which the report says reduces energy consumption expenses but does little to offset expensive demand-related charges, a properly sized solar and battery storage system can eliminate nearly all electricity expenses, resulting in an annual electric utility bill of less than a few hundred dollars.
– The addition of storage technologies has the potential to nearly double stand-alone solar electricity bill savings at about a third of the cost of solar. For example, the report says the addition of an $112,100 battery storage system to a $385,000 solar installation increased savings from $15,000 per year to $27,900, an 85% increase in savings for only a 29% increase in cost.
– The addition of battery storage to solar improves the economics of each property analyzed across all utility territories, reducing project payback by over three years in some cases.
“Our analysis, which is based on data from real buildings, shows that adding battery storage to a solar PV system installed on an affordable housing property in Southern California could increase the annual savings on a property owner’s electricity bill to 99 percent, which is nearly double the savings of what a solar-alone system can provide” says Seth Mullendore, a program manager at the Clean Energy Group.
The report also finds that affordable multifamily housing property owners in two utility territories – Southern California Edison and San Diego Gas & Electric – have the potential to increase savings by nearly 100% over solar alone by adding storage, while increasing upfront investment by less than 30%, essentially eliminating their annual electric bills.
“Many affordable housing owners are interested in exploring energy storage, both for the economic benefits and improved resiliency of a property,” says Wayne Waite, policy director at the California Housing Partnership. “This report fills the information gap for owners so they can better understand these emerging technologies.”
The report, titled “Closing the California Clean Energy Divide,” is available here.