Large-scale battery energy storage in the U.S. has grown 2 GW in operational power capacity in the last decade. Several factors have allowed the battery energy storage market to grow, including decreasing costs and improvement in technology. The median energy capacity costs for large-scale batteries was roughly $2,150/kWh in 2015 and decreased by 61% in 2017 to a median of about $800/kWh. While each technology has its strengths and weaknesses, lithium-ion makes up the majority of utility-scale battery systems in the U.S. due of cost declines and a high energy density. Both lithium-ion and flow battery technologies are projected to see significant cost declines in the coming years. New battery technologies are also being developed, such as the iron-air-exchange battery that could potentially provide long-duration energy storage for less than $20/kWh. These cost declines coupled with policy incentives will drive increased demand for battery storage from utilities, commercial and industrial (C&I) consumers, and residential consumers, leading to continued growth in the battery market in coming years.  

Battery energy storage projects provide utilities a unique opportunity to take advantage of a variety of benefits. The most common application of battery storage is for frequency regulation, which helps to balance any momentary differences between supply and demand at any time. Batteries are also becoming increasingly common in pairing with renewable energy projects. To maximize the benefits of renewable energy projects, batteries can store excess energy to be deployed during times of higher demand when prices are higher. This helps to reduce costs for the co-op and for consumers. Many electric cooperatives have already deployed battery storage projects. Interest among electric co-ops in deploying battery energy storage is growing, and will likely accelerate as more experience is gained, costs continue to fall, and technological advances improve the performance of batteries. As co-ops look towards resiliency, batteries will play a critical role in providing backup power to the grid.