WEST LEBANON, N.H., March 22, 2011 /PRNewswire/ -- A fourth patent has been awarded by the US government to SustainX, a fast-growing technology venture in Lebanon, New Hampshire. SustainX has developed a transformational technology for utility-scale energy storage using compressed air. The new patent covers methods for controlling the way air is expanded and compressed in such systems.
Energy storage is essential to making the electrical grid more efficient, according to the US Department of Energy, but affordable storage technologies have so far been lacking. To meet this need, SustainX compresses air by using electricity to drive pistons inside cylinders. The resulting high-pressure air is stored in above-ground vessels. To release energy at a later time, the system uses stored air to drive the same pistons, which in turn drive an electric generator.
The company's new patent, No. 7,900,444, covers the use of measurements of conditions inside the cylinders, such as temperature or pressure, to keep the air at a nearly constant temperature during compression and expansion. One method for controlling the air's temperature is to spray water through it. By maintaining near-constant ("isothermal") air temperature, SustainX significantly improves the efficiency of compressed-air energy storage.
"This patent, along with the three others awarded to SustainX during the last year, further establishes the company as the world leader in isothermal compressed-air energy storage," says President and CEO Thomas Zarrella.
This new patent, combined with previously issued patents on staged compression and expansion and on heat exchange with a thermal well or the environment, strengthens SustainX's IP position in the field of compressed-air energy storage. The issued patents are general enough to cover a wide range of isothermal systems, including both existing SustainX systems and those in development.
SustainX was founded in 2007 by engineers at the Thayer School of Engineering at Dartmouth College. It has received funding from the National Science Foundation Small Business Innovation Research Program and the Energy Storage Program at the US Department of Energy, as well as equity investments from top-tier venture investors Rockport Capital (with offices in Menlo Park, CA and Boston), Polaris Venture Partners (Boston and Seattle), Cadent Energy Partners (Stamford, CT and Houston), and GE Energy Financial Services, a unit of GE.
The company's transformative energy storage technology, which it terms ICAES™ (for Isothermal Compressed-Air Energy Storage), uses no fuel. SustainX's competitive advantages stem from its proprietary thermodynamic and hydraulic control innovations, a design centered on mature industrial components, and reliance on ambient-temperature, 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.