Balancing supply and demand of renewable electricity can be a challenge, particularly due to the intermittency of solar and wind sources. Effective utility-scale battery options would bolster state renewable energy systems by saving excess energy for future use, especially during times of low generation. Batteries are particularly beneficial to solar power systems due to the cost benefit of reducing curtailment. States could support battery technology by establishing long-term procurement goals for utility-scale and distributed energy storage. This storage mandate would reinforce the value that energy storage provides the grid and help reduce the cost of wasted energy.

Barriers to increasing statewide solar integration include concerns from state utilities regarding load imbalances and grid reliability. As demonstrated in California, the technology is available to support widespread solar integration. In 2013, the California Public Utilities Commission (PUC) required that the three large investor-owned utilities obtain 1,325 MW of combined storage by 2020, with installations operational by 2024. The California PUC also provisionally extended storage benefits to distributed solar systems by providing fee exemptions and streamlining interconnection approval for small, net-metered systems paired with storage. These measures can save customers up to $3,700 in extra fees. Since the mandate, the two largest utilities have procured 325 MW of various storage technologies. To chart these energy futures, state utilities could be required to incorporate energy storage into their integrated resource plans and provide different scenarios based on solar output and storage integration.

While the California mandate applies to only investor-owned utilities, states could include municipal utilities and rural electric cooperatives at a smaller scale. For example, states could direct these electric providers to invest in at least one storage demonstration project that has a minimum capacity of one megawatt-hour. Oregon has taken a similar approach by requiring utilities to meet a 5 megawatt-hour storage minimum. State legislatures and public utility commissions could establish strong policies that signal a commitment to energy storage. Enacting a storage mandate would enable greater utility-scale battery deployment and help states achieve their renewable energy goals.