As the energy storage industry continues to evolve, it is important for electric company utility planners to be aware of the battery energy storage system (BESS) landscape. For this study, the Electric Power Research Institute (EPRI) hired a third-party engineering procurement and construction contractor to solicit quotes from energy storage developers and then develop project construction estimates for five different energy storage technologies. EPRI has provided comments on the equipment and construction estimates that members can use to inform their decision making as they develop energy storage projects.
This report provides technology overviews, developer references, technology trade-offs, and case study examples of capital costs, operation and maintenance costs, and performance data for five different energy storage technologies at various levels of commercialization maturity. The energy storage technologies covered within this report are traditional flow, hybrid flow, lithium ion, zinc-air, and sodium-sulfur.
Lithium ion has the lowest capital expenses and operating expenses of the mature technologies and the highest roundtrip efficiency. There is still uncertainty surrounding ongoing OPEX costs due to limited experience with utility-scale systems. The costs presented in this study are based on examples that use assumptions to determine component replacement schedules. These assumptions can have a material impact on overall costs. As the industry gains experience, these estimates will be continually refined. Technologies such as zinc-air and sodium-sulfur may have lower estimated costs based on vendor quotations, but these technologies represent a much higher risk due to the limited number of utility-scale deployments and the small number of technology developers. Each project deployment needs to be analyzed independently as each BESS technology offers different performance trade-offs.