On Wednesday, Duke Energy, one of the largest energy holding companies in the U.S. and a utility provider to nearly 8 million customers in the southeastern United States, announced that it is partnering with Malta Inc., a thermal energy storage startup that was hothoused at (Google’s) X (a.k.a. the Moonshot Factory), on a landmark, federally funded study. With support from the U.S. Department of Energy, Duke and Malta will integrate Malta’s 100 MW heat energy storage system into the existing infrastructure of one of Duke Energy’s six coal plants in North Carolina.
The goal of the year-long study is to evaluate the socioeconomic, environmental and operational benefits of converting retiring coal units into long-duration, zero-emissions energy storage systems.
Malta Inc.’s system stores electricity either directly from a power plant or from the grid by converting electricity into thermal energy (heat and cold). Heat is stored in molten salt, a decades-old and proven method of storing thermal energy. Cold is stored in an antifreeze-like solution with components and subsystems widely used in the liquefied natural gas industry.
The system operates like a conventional power plant. When electricity is needed, the thermal energy powers a heat engine to produce clean, reliable energy.
“Malta is excited to work with Duke Energy to identify cost-effective, common-sense paths forward for fossil assets that consider all stakeholders,” said Malta CEO Ramya Swaminathan. “For utilities like Duke Energy to meet their net-zero carbon emissions goals, major advancements in technology are needed. The Malta system could be part of the solution by providing zero-emissions, load-following technology that provides reliable, resilient and around-the-clock power.”
Though the study will focus on the energy industry’s current need for 10-12 hours of energy storage, the Malta system can be configured to store up to 200 hours of energy storage.
“Duke Energy is investing in innovation as part of our clean energy transformation plan to achieve net-zero carbon emissions by 2050,” said Regis Repko, senior vice president of Duke Energy’s Generation and Transmission Strategy organization. “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. We expect the results to influence the future of energy and apply to our larger generation fleet.”
Besides evaluating the technology and engineering feasibility of the project, the study will also include a broader look at the socioeconomic impacts of the study. This includes job retention, as current coal-fired plant workforces could transition to operating the mechanically similar Malta system, preserving jobs and a portion of the local propery tax base. Additionally, adding more utility-scale, long-duration storage could allow the company to integrate more intermittent renewable energy sources, like solar, providing additional environmental benefits.
Last month, Malta Inc. announced that it, together with Texas-based listed utility Vistra and the Southwest Research Institute (SwRI), has received a (separate) Department of Energy grant to study the performance of Malta’s energy storage system at a natural gas-powered plant.
Duke Energy has committed to a 50 percent reduction in its carbon emissions by 2030, and net-zero carbon emissions by 2050. It is currently on track to operate or purchase 16,000 megawatts of renewable energy capacity by 2025.
