This paper examines the critical role of energy storage innovation in achieving environmental targets. Traditional macroeconomic models have often overlooked the importance of enabling technologies to overcome the intermittency of clean energy. We incorporate storage technology into an endogenous growth model. Due to the complementarity between renewables and storage technology, the productivity of storage technology becomes a key determinant of the private incentives to innovate in clean energy relative to fossil fuels. We calibrate it to the U.S. economy and find four main results: First, models that neglect the role of energy storage overestimate the effectiveness of climate policy. Second, clean and dirty energy are currently complementary inputs due to the low productivity of storage technologies. Third, the low productivity of storage technologies may have reduced clean innovation with a magnitude similar to the shale gas boom. Fourth, current policy such as the Inflation Reduction Act is not sufficient to decarbonize U.S. energy supply. To reach decarbonization targets, we need additional policy effort to close the productivity gap between renewables and storage technology.