SustainX has created a transformative technology for compressed-air, utility-scale energy storage.

Recently patented technology created by SustainX is changing the game for utility energy storage. A startup in West Lebanon, New Hampshire,  SustainX recently received $20 million in venture capital to test its compressed-air energy storage technology on a large scale. Proof of concept has been shown in their 40-kilowatt prototype and a one-megawatt system is scheduled for deployment next year.

What is it? Isothermal compressed-air energy storage.

Boasting a system that is low cost, low maintenance, scalable and transportable, the SustainX energy storage system (ESS) also requires no fuel and emits no greenhouses gases. Using pistons, rather than turbines to generate electricity, the company has reduced costs and increased the range of air pressure at which it can generate electricity.

Conventional compressors have a higher rate of heat loss than the SustainX technology and utilize underground storage. SustainX uses above ground storage tanks and it compresses air by using electricity to drive pistons inside cylinders. To release energy, expanding air drives the pistons in reverse, which drives a generator. A fine water spray inside the cylinders absorbs heat generated during compression. The hot water is stored and sprayed back into the cylinders during expansion, so the system needs no additional fuel to heat the air. The water spray increases the energy efficiency of the process from 54 percent to 95 percent, says company cofounder Ben Bollinger.

"We do aboveground compressed-air energy storage at belowground prices," says cofounder and vice president Dax Kepshire.

SustainX is intended for wind and solar energy providers as a tool for storing energy captured during off-peak hours that can be used when demand is higher. The ability to store energy creates a more stable energy grid and improves the feasibility of micro-grids in rural or isolated areas.

SustainX is one of a handful of companies working on isothermal compressed-air storage technology. The other major player in the field, Newton, Massachusetts-based General Compression, recently raised over $50 million for its system, which uses a wind turbine to power the compressor and air expansion unit. There are only two operating compressed-air energy storage installations in the world, one in Alabama and one in Germany, totaling 440 megawatts. Two projects are under construction in the United States: a 300-megawatt facility in Kern County, California, and a 145-megawatt facility in Watkins Glen, New York.

SustainX could eventually provide a more reliable grid, accelerate the penetration of clean renewable energy sources into the market, and reduce overall emissions related to current renewable technologies.

Source: Technology Review