Although pumped hydroelectric storage makes up most of the total electricity storage capacity in the United States, nonhydro storage has doubled in electric power sector capacity from 160 megawatts (MW) to nearly 350 MW over the past five years.
About 98% of the U.S. electricity storage is pumped hydroelectric storage, where water is pumped to a higher-elevation reservoir during off-peak demand and then run back down through a turbine during peak demand. However, pumped storage facilities are expensive, making additional capacity builds in pumped storage infrequent.
Nonhydro storage systems, which include compressed air, batteries, and flywheels, can provide , including regulating the grid’s frequency on a second-to-second or minute-to-minute basis and fast-ramping capacity to cover sudden and unexpected gaps between electric demand and supply. The economic value of these services is beginning to be captured in the price of wholesale electricity through several recently implemented policies.
Several recent Federal Energy Regulatory Commission (FERC) orders support the use of electricity storage by creating or improving market incentives for these ancillary services. to include energy storage technologies and to streamline the time and cost associated with interconnecting new energy resources.
States have actively begun developing energy storage-related policies as well. California created an , which discusses the need for a competitive marketplace for distributed technologies, including energy storage.
Government agencies are not the only entities devoting attention to energy storage services. Hawaiian Electric Co. (HECO), the utility serving most of Hawaii’s population, issued a and proposed to install up to 5 GW of battery storage capacity beginning in 2018.
Principal contributor: Cara Marcy