South Korean battery developer Kokam has deployed two lithium nickel manganese cobalt (NMC) oxide energy storage systems (ESSs) for frequency regulation on the South Korean electricity grid. A 24 MW/9 MWh system and a 16 MW/6 MWh system, in concert with a Kokam 16 MW/5 MWh lithium titanate oxide ESS system installed in August 2015, provide Korea Electric Power Corp. (KEPCO) with 56 MW of energy storage capacity for frequency regulation.

The Kokam 24 MWh Energy Storage System for utility frequency regulation in South Korea. Image source: Kokam The 24 MW system is considered one of the world’s largest-capacity lithium NMC ESS used for frequency regulation. The three systems together are slated to deploy 500 MW of battery-based energy storage by 2017. These systems are expected to deliver an estimated annual savings of $13 million in fuel costs for the utility, providing fuel cost savings three times larger than the ESSs' purchase price over the systems' lifetimes. In addition, by reducing the amount of fossil fuels consumed for frequency regulation, the Kokam ESSs will help reduce KEPCO's greenhouse gas emissions.

Designed for high-power energy storage applications such as frequency regulation, wind or large solar power system ramp rate control, Uninterrupted Power Supply (UPS) and voltage support, Kokam's Ultra High Power NMC battery technology delivers high energy density, long cycle life and, what the manufacturers says are, better charge, discharge and max power rates.

A higher density enables 2.4 MWh of energy storage to be installed in a 40-foot container, compared to 1-1.5 MWh of energy storage for standard NMC batteries. These batteries can also last up to 10,000 cycles, compared to 3,000 - 5,000 cycles for standard NMC technologies, and feature charge, discharge and max power rates of 4C, 8C and 15C, respectively, compared to 2C, 3C and 4C for competitors.