Achieving deep decarbonization in the US will require days, and potentially weeks, of energy storage to be available – but today’s technologies only provide hours of capacity. Evolving technologies, like hydrogen, will be needed for long duration storage that can extend to weeks of capacity. While the needs of our future grid are still uncertain, policymakers can and should support the evolution of long-duration, clean energy storage by encouraging technology innovation and enabling financing and procurement models that align with long-duration storage.
A recent growth in targets for ambitious clean energy use and net zero greenhouse gas emissions has increased interest in the role of utility-scale storage, including long-duration energy storage, to achieve deep decarbonization of the power sector.
In future deep-decarbonization scenarios, energy storage holds the potential to address multiday weather-related events that lower the production of renewable energy, as well as seasonal differences in renewable energy resource availability that can last for weeks.
Today’s storage technologies provide only hours of storage, though with design and operational changes, compressed air energy storage and pumped hydro storage capacity could be stretched into days.
Other, less mature storage technologies may evolve to provide long-duration storage that compensate for seasonal variations in renewable energy supply, for example, technologies that create hydrogen through low-carbon processes.
Recent storage deployments in the United States have been driven by state storage mandates, utility investment, frequency regulation markets and declining battery costs.
Policymakers can play an important role in driving innovation, encouraging cost reductions and assessing the benefits of storage to provide greater options for maintaining reliability in future decarbonized grids through research and development, demonstration projects and regional studies. New approaches to financing, planning and procurement could reduce barriers to the adoption of long-duration storage technologies.