WEST LEBANON, N.H., Sep. 28 — SustainX, Inc., a New Hampshire-based startup developing a transformational technology for utility-scale energy storage using compressed air, has received its first U.S. patent. Patent no. 7802426, which will remain in effect until June 2028, contains method claims for keeping air at an approximately constant temperature as it is expanded or compressed in pneumatic cylinders. The patent is believed to be the first issued for isothermal compressed-air energy storage.
In an isothermal compressed-air cycle, heat must be continuously removed from air as it is compressed and added as it is expanded. Claims of the new patent cover SustainX’s proprietary method for performing this process. During compression, heat is transferred to, for example, the ambient atmosphere or to a body of water; during expansion, it is harvested — e.g., from either of those sources or, in the case of a cogeneration-enhanced system, from a source of low-grade waste heat such as a thermal power plant.
“The issuance of this patent is a milestone for SustainX,” according to president and CEO Thomas Zarrella, “because it solidifies the commercial position of our core technology, isothermal gas cycling in pneumatic cylinders. There is an increasingly urgent demand for bulk energy storage in power grids, and our technology is a leading candidate for meeting that demand.”
SustainX was spun-out of the Thayer School of Engineering at Dartmouth College in 2007 and has received funding from the National Science Foundation (NSF) Small Business Innovation Research (SBIR) Program, the Energy Storage Program at the U.S. Department of Energy (DOE), and equity investments from top-tier venture investors Polaris Venture Partners and Rockport Capital.
The company’s transformative energy-storage technology, which it terms ICAES™ (for Isothermal Compressed-Air Energy Storage), uses electrical energy to compress air nearisothermally (i.e., at approximately constant temperature), stores it aboveground in commercial gas storage containers, and expands it near-isothermally to generate electricity. No fuel is involved. The company’s competitive advantages stem from their proprietary thermodynamic innovations, a design centered on mature industrial components, and reliance on an ambienttemperature, nontoxic working fluids.
SustainX ICAES is targeting the emerging market for bulk (grid-scale) energy storage being created by the growth in renewable generation, and aims to disrupt costly “peaker” plants that burn natural gas or other polluting fuels.