New York regulators in April approved construction of a 20-MW energy storage system at the site of an operating coal-fired power station near Union, Broome County. When operational, the $22.3 million project, owned by AES ES Westover LLC—an AES Corp. subsidiary—will use the technology to participate in New York’s growing day-ahead market for ancillary services and regulation.

The energy storage technology is based on prototypes of Lithium-Titanate material battery cells developed by AES and other suppliers. Basically, it consists of lithium ion battery stacks, AC-to-DC power conversion systems, HVAC units, and control systems. Tests of the system in 2008 conducted by AES, with Dutch company KEMA as a consultant, at a substation owned and operated by Indianapolis Power & Light showed the feasibility and commercial potential for using systems of advanced lithium ion battery cells to help maintain the stability of the grid. In its validation report, KEMA went so far as to say that the system could respond with up to full power in milliseconds to control commands.

AES will build the project in two phases at Westover Generation Plant, 175 miles northwest of New York City, starting in the second quarter of 2010. That plant includes the 84-MW Unit 8, which entered service in 1951, and a non-operating 44-MW Unit 7, completed in 1943. AES will connect the battery project to the power grid using Unit 7’s facilities.

Based on the pilot and demonstration projects, the project will comprise 10 containers, each 53 feet long and capable of housing inverters and 2-MW DC battery subsystems. The units will then be connected through standard electrical industry transformers, switchgear, and protective relays to the high-voltage system. According to developers and the New York Public Service Commission (PSC), the project will be able to provide or absorb some 5 MWh to and from the system.

The site will reportedly require minor modifications to install foundations to support the energy storage units, but no new interconnection facilities will be required to interconnect the project to the New York State Electric & Gas Corp.’s transmission system. The PSC said in a statement that an interconnection request has already been filed for the project with the New York Independent System Operator (NYISO) as part of NYISO’s Small Generator Interconnection Procedures.

C O R R E C T I O N: This version of the June 1, 2010, story about the planned 20-MW energy storage system in New York reflects that AES has not publicly revealed the suppliers of the lithium ion battery cells AES; POWER had erroneously said that Altairnano and Parker SSD had supplied the cells. The story also notes that the 2008 tests of the system were conducted by AES with KEMA as its consultant. Finally, the project will comprise 10 containers each 53 feet long, rather than tall. POWER regrets the error.