NRStor to deploy Ont.’s first utility-scale CAES project

Compressed air energy storage capacity services project will be based in an underground salt cavern.

November 24, 2015   by PLANT STAFF

TORONTO — Ontario’s Independent Electricity System Operator (IESO) has chosen NRStor Inc. to deliver compressed air energy storage capacity services (CAES ) to the grid.

NRStor, and energy storage developer based in Toronto has partnered with General Compression Inc., a technology developer of fuel-free compressed air energy storage systems, to develop an underground salt cavern in Southwestern Ontario.

When operational, this will be the largest commercial CAES project in Canada.

This project is part of IESO’s procurement of up to 50 megawatts of energy storage.


General Compression, based in West Roxbury, Ma., provides a near-isothermal compressor/expander module that stores energy in compressed air and warm water. A proprietary heat transfer method captures, stores, and re-introduces heat, eliminating the need for fuel input.

The compressed air is stored in large underground reservoirs that can provide hundreds of hours of compression and expansion at a time. This technology allows for utility-scale projects to operate fuel-free for long durations (up to 200 or more hours) at a variety of power ratings (2 to 1,000-plus megawatts).

The system requires no fuel input, produces zero greenhouse gases, and is not dependent on colocation with a supplemental heat source.

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