One of the ways to store a large amount of electrical energy is through lithium-ion batteries. In fact, the PJM campus currently houses two megawatts worth of lithium-ion batteries in an array (owned and operated by AES Energy Services LLC, a subsidiary of The AES Corp., a PJM member). The large series of batteries can change whether it puts energy into or receives energy from the grid in less than one second and helps PJM quickly balance short-term variations in energy use.
Of course, there are a number of other methods of energy storage, including flywheels, electric vehicles and thermal storage devices such as water heaters or space heaters. Visit PJM’s Learning Center for more about how PJM is integrating energy storage into the grid with a number of pilot programs.