(Credit: Pixabay)Malta, an energy storage solutions company, is teaming up with Duke Energy to study the socioeconomic, environmental, and operational benefits of converting retiring coal units into long-duration, zero-emissions energy storage systems.
Malta is developing a pumped heat energy storage system that leverages subsystems, components, and thermodynamics in an energy storage application. By leveraging existing subsystems from well-established industries, the system relies on decades of performance data to ensure safe, resilient operations.
The 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. 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.
The study's environmental benefits include adding more utility-scale, long-duration storage could allow the company to integrate more renewables like solar, particularly when the sun isn't shining. The operational benefits include long-duration energy storage could increase flexibility, reducing wear on generation assets by decreasing the number of times a unit needs to turn on and off.
A US Department of Energy grant is funding the year-long study of the emerging technology. The Department of Energy announced the grant in March, and the team is identifying which of Duke Energy's six coal plants in North Carolina is best suited to serve as the test site.
Similarly, just last month, J-POWER USA Development and funds managed by affiliates of Fortress Investment Group have agreed to jointly pursue development of Birchwood Solar, a 50 MWac solar plant, and Birchwood Storage, a 190 MWac energy storage facility. These projects would convert Birchwood Power, a coal plant, which has been in operation since November 1996, into facilities that will generate and store clean renewable energy.
