Compressed Air Storage Breakthrough
September 26, 2013
Simple idea. Storing energy as compressed air. It’s been done before, but with a fossil fuel assist that made it more carbon intensive and expensive.
This is a big deal. There will probably not be a one size fits all answer to energy storage – and storage is not needed nearly as much as some people think, but improvements like this will give planners more options and flexibility in designing distributed systems in coming years.
SustainX, an energy storage technology developer, has completed construction and begun startup of the world’s first megawatt-scale isothermal compressed air energy storage (ICAES) system (detailed description available here). The system stores and returns megawatts of electricity to provide long-term grid stability and support integration of renewable energy sources like wind and solar.
The 1.5-megawatt isothermal compressed air energy storage system is located at SustainX headquarters in Seabrook, New Hampshire. It takes electricity from the grid and uses it to drive a motor that compresses air and stores it isothermally, or at near-constant temperature. To do so it captures the heat produced during compression, traps it in water, and stores the warmed air-water mixture in pipes. When electricity is needed back on the grid, the process reverses and the air expands, driving a generator. No fossil fuel is needed to reheat the air and no emissions are produced, making ICAES a safe and sustainable energy storage solution.
“Our isothermal CAES technology is a dramatic improvement over other bulk energy storage methods because it uses no fuel, produces no emissions, is power- and energy scalable, and can be sited virtually anywhere,” said Tom Zarrella, SustainX president and CEO. “Thanks to numerous innovations on core system elements, SustainX has developed, proven, patented and now built the key enabling technologies for isothermal CAES. We believe this places our company at the forefront of large-scale energy storage system development and commercialization.”
The system can be scaled in both power (megawatts) and energy (megawatt-hours) depending on the application, and can be located where needed thanks to its use of standard pipeline storage and clean, emission-free operation. Because it’s based on proven mechanical principles and mature industrial components, the system has a 20-year operating life with a very low levelized cost of energy, enabling cost-effective, large-scale storage of electricity. Unlike chemical battery systems, ICAES performance does not degrade over its lifetime or need frequent replacement. No hazardous materials are used.
SustainX isothermal compressed air energy storage technology is a significant improvement over conventional compressed air energy storage (CAES) systems, which have existed since the 1970s. CAES systems burn fossil fuel and are greatly limited by the need for specific geological locations (i.e. caverns) for air storage—as well as substantial investments in time and money. Because of these limitations, there are only two such installations worldwide. SustainX’s ICAES is the first megawatt-scale compressed air energy storage system built anywhere since 1991, and represents an opportunity to expand the availability and use of this bulk energy storage method.