Energy storage for grid frequency regulation
The two new Kokam systems have been operational since January 2016, along with a Kokam 16 MW/5 MWh lithium titanate oxide (LTO) energy storage system deployed in August 2015. They now provide South Korea’s largest utility, Korea Electric Power Corporation (KEPCO), with 56 MW of energy storage capacity for frequency regulation.
Together these three systems are part of the world’s largest ESS frequency regulation project, which is scheduled to have deployed 500 MW of battery-based energy storage when it is completed in 2017.
Reducing energy costs
In addition to improving grid reliability, the Kokam ESSs will enable KEPCO to improve its operational efficiency by reducing its need for spinning power generation reserves. This will allow KEPCO to shift energy generation to lower-cost, more efficient power plants, and reduce ‘wear and tear’ on all of its power plants.
For example, these three Kokam energy storage systems will deliver estimated annual savings of US$13 million in fuel costs, providing fuel cost savings three times higher than the ESS purchase price over the systems’ lifetimes. In addition, by reducing the amount of fossil fuels burnt for frequency regulation, the ESSs will help reduce KEPCO’s greenhouse gas emissions.
Kokam energy storage systems for KEPCO
‘Our energy storage systems provide KEPCO with the performance it needs to precisely and cost-effectively regulate frequency on the South Korean grid, helping it ensure the stability of this grid, improve its operational efficiency, and lower its greenhouse gas emissions,’ says Ike Hong, Vice President of Kokam’s Power Solutions Division.
‘Kokam’s 56 MW of energy storage systems are making a major contribution to the stabilisation of our grid,’ adds Dr Hwang Woohyun, Senior Vice President and Head of the Innovative Energy Business Division at KEPCO. ‘We hope to continue to cooperate with Kokam to develop energy storage projects that improve grid reliability, lower our operational costs, and reduce our environmental impact.’
Ultra high power lithium NMC battery technology
The new 24 MW and 16 MW lithium NMC ESSs utilise Kokam’s innovative ultra high power NMC battery technology. This is 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 offers higher energy density, which enables 2.4 MWh of energy storage to be installed in a 40 ft (12 m) container, compared to 1~1.5 MWh of energy storage for standard NMC batteries. In addition, the ultra high power NMC batteries can last up to 10 000 cycles, compared to 3000–5000 cycles for standard NMC technologies, increasing an energy storage system’s expected life.
Kokam says that its ultra high power NMC battery technology has charge, discharge, and maximum power rates of 4C, 8C and 15C, respectively, compared to 2C, 3C and 4C for competitors, which enables systems to receive and dispatch more power when needed. And with a heat dissipation rate that is claimed to be 1.6 times better than standard NMC technologies, the ultra high power NMC batteries can be used at a higher rate for longer periods of time with no degradation in battery life or performance.
The systems use Kokam’s KCE 40 ft container, which features a direct cooling design, in which the container’s heating, ventilation and air-conditioning (HVAC) system only regulates temperatures inside the system racks, rather than the entire container. This results in a 70% lower air-conditioning auxiliary load than standard containers.
Battery manufacturing experience
Kokam specialises in the development of advanced battery technologies for demanding energy storage system applications, including frequency regulation, which needs systems that deliver high power, fast recharge rates, and long cycle lives.
‘With some of the most innovative battery and other energy storage technologies on the market, 26 years of lithium-ion battery system manufacturing experience, and 95 MW of energy storage system capacity in operation around the world, Kokam has positioned itself as a leader in the rapidly growing energy storage system market,’ says Ike Hong.
He continues: ‘For applications such as frequency regulation, renewable energy smoothing, transmission and distribution investment deferral, demand response and peak load shaving, Kokam provides customers with advanced battery and other energy storage systems technologies that deliver superior performance at a competitive price.’
Kokam has provided a wide range of lithium ion/polymer battery solutions to customers in more than 50 countries and many different industries, including the military, aerospace, marine, electric vehicle (EV), and energy storage system (ESS) markets.