Soaking Up the Sun: Battery Investment, Renewable Energy, and Market Equilibrium

We develop a dynamic competitive equilibrium model of battery adoption and operations to evaluate the social value and adoption trajectory of utility-scale batteries and examine policy counterfactuals. The first battery unit breaks even in 2027 when renewable energy share reaches 52% and expected capital costs are $259/kWh. While the competitive market will install 10 MWh by 2030, competitive adoption does not reach 5,000 MWh until 2043 because the marginal value of investment sharply declines in aggregate capacity. California's 1,300 MW battery mandate implies subsidies of 49% and creates deadweight losses of $433 million relative to a competitive battery market.