Announced November 25, 2009, SustainX has received a $5.39 million award from the US Department of Energy to develop its technology for storing large amounts of energy using compressed air.
Energy storage is a crucial technology for the smart grid, addressed by SustainX by storing energy in the form of compressed air. Electrically-driven hydraulic pumps are used to compress air to high pressure (up to 3,000 psi) for storage above-ground in standard industrial pressure vessels. This air is later expanded, powering a hydraulic motor that drives an electric generator. The technology uses isothermal cycling -- that is, the air is kept at a constant temperature -- coupled with staged hydraulic compression and expansion to deliver efficient, cost-effective energy storage.
SustainX's technology relies on off-the-shelf mechanical components, contains no toxic materials other than ordinary hydraulic fluid, and emits no air pollution or effluents. The company anticipates that its units will have extremely long cycle lifetime -- that is, will be able to charge and discharge thousands of times before needing replacement -- and will achieve high round-trip efficiency, allowing recovery of 70%-80% of the energy required to charge them. Using simple materials, reliable off-the-shelf components, and efficient air-handling techniques based on basic thermodynamic principles will result in breakthrough cost savings.
Each SustainX energy-storage unit acts, in effect, like a large storage battery. No fuel is needed to run the unit. A cluster of such units will produce megawatts of electricity for hours on end.
SustainX was spun out of Dartmouth College last year and now employs ten people at its site in West Lebanon, New Hampshire.
Website: http://www.sustainx.com/