Energy Storage

World's Largest Concrete Thermal Energy Storage Pilot Successfully Tested

EPRI, in collaboration with Southern Company and Storworks, has recently completed testing of a pilot concrete thermal energy storage (CTES) system at Alabama Power’s Ernest C. Gaston Electric Generating plant (Gaston) marking the largest such pilot in the world. The technology was developed by Storworks.

The 10-MW-hour-electric (MWhe) energy storage solution (Figure 1) is charged using heat from supercritical steam generated by Gaston’s Unit 5. As designed, high-pressure steam from the power plant flows through tubes, heating the concrete, which stores the thermal energy until it is returned to the power plant by converting feedwater into steam to generate electricity in response to grid demand. The project received funding from the U.S. Department of Energy under award DE-FE0031761.

1. A 10-MWhe first-of-its-kind concrete energy storage demonstration was constructed and successfully tested at Southern Company’s Gaston coal-fired generating plant. Courtesy: Storworks

The technology can be applied to existing or new thermal power plants, including coal, natural gas, nuclear, or concentrating solar power. The core technology can go beyond electric power to applications including decarbonizing industrial heat.

“Advancements in long-duration energy storage are key to unlocking the full potential of variable renewable energy resources on the path to net-zero,” said Neva Espinoza, EPRI vice president of Energy Supply and Low-Carbon Resources. “As the power sector navigates a highly complex transition, CTES could play an important role in efficiently delivering the reliable and affordable electricity society depends on.”

The CTES pilot system, temporarily integrated into the unit at Gaston, proved the technology’s potential to store thermal energy for conversion to electricity when combined with thermal power plants. The original goals of the project were exceeded, as steam production at several pressure levels was demonstrated. More than 80 energy charge and discharge cycles were also successfully performed over 700 hours of total operation.

“Southern Company is deeply committed to advancing the transition to a net-zero future, while ensuring the delivery of clean, safe, reliable, and affordable energy,” said Dr. Mark S. Berry, Southern Company senior vice president of Research, Environment, and Sustainability. “As a leader in research and development, Southern Company is exploring the potential of CTES technology to help decarbonize electricity production. We are excited to be pioneering this groundbreaking research demonstration in collaboration with EPRI, Storworks, and our subsidiary, Alabama Power.”

“We appreciate the vision and support from our partners that made this pilot demonstration possible,” said Scott Frazer, co-founder of Storworks. “Low-cost long-duration energy storage is increasingly critical in the shift to low-cost intermittent renewable energy, and the Gaston project represents an important milestone in advancing the commercialization of our technology. With industry-leading low cost, Storworks’ modular system can be tailored to a range of applications for both power plants and industrial decarbonization solutions.”

CTES can give grid operators greater flexibility by allowing them to store energy when it is not needed and then provide it when it is most valuable. EPRI will continue to evaluate the feasibility of CTES and other long-duration energy storage options as part of the clean energy transition.

POWER edited this content, which was contributed by EPRI’s Communications department.

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