May 27, 2021: Thermal energy storage company Malta and Duke Energy, the North Carolinian utility, announced on May 19 they would work together to study the feasibility of converting decommissioned coal plants into long-duration energy storage systems by integrating pumped heat into existing infrastructure.
The US Department of Energy is funding a year-long study into using Malta’s 100MW, 10-hour pumped heat energy storage system into the existing infrastructure at one of Duke Energy’s coal plants in the state.
The system will store electricity from a power plant or from the grid by converting electricity into thermal energy. Heat is stored in molten salt, which Malta says is a decades-old, proven method of storing thermal energy, and cold energy is stored in an antifreeze-like solution with components and subsystems used in the liquefied natural gas industry.
“The system operates like a conventional power plant,” says Duke Energy. “When electricity is needed, the thermal energy powers a heat energy to produce clean, reliable energy.”
“For years, Duke Energy has actively evaluated emerging technologies, and the Malta study marks the first time we will evaluate long-duration thermal energy storage,” said Regis Repko, senior vice president of Duke Energy’s Generation and Transmission Strategy organization.
“We expect the results to influence the future of energy and apply to our larger generation fleet.”