FirstLight wants to add new peak capacity duration this winter

In order to help with peaking capacity this winter in the ISO New England region, FirstLight Hydro Generating Co. on Aug. 8 requested a temporary license change at the Federal Energy Regulatory Commission for its Northfield Mountain Pumped Storage (NMPS) facility on the Connecticut River in Massachusetts.

FirstLight is requesting a temporary change in the water surface elevation limits of the NMPS facility’s upper reservoir for the period Dec. 1, 2014, through March 31, 2015, to increase the operating range of the upper reservoir elevation from the current 1000.5 feet mean sea level (msl) and 938 feet msl, to 1004.5 feet msl and 920 feet msl.

“The requested increase in operational flexibility will provide ISO New England Inc. (ISO-NE) with additional resources to address the reliability challenges it anticipates in the Northeast this winter,” the application said. “FirstLight requests Commission action on the application no later than November 1, 2014.”

Northfield Mountain is a peaking facility, generating power by releasing water through the pump-turbine-generator units to the Turners Falls Impoundment and then pumping water back up to the upper reservoir for storage during periods of low or off-peak electric load. It is the most flexible station in the region, with the capability to generate from 0 to full output (1,143 MW) in six to eight minutes.

The altered NMPS facility could serve as an additional operating reserve in New Englandand provide a flexible, quick start resource, to address fuel supply-related or other contingencies that may arise this winter.

With the retirement of the 625-MW Vermont Yankee nuclear plant and Salem Harbor coal- and oil-fired station (about 587 MW), ISO-NE will rely more heavily on remaining generation, such as the NMPS Project, capable of providing reliability, flexibility, and important fuel diversity when gas supply conditions could restrict the output of gas-fired generators, FirstLight noted.

There will be no change in the hydraulic capacity of the four reversible pump turbines and no change in the maximum generating capacity (1,143 MW) or maximum pumping capacity (1,000 MW) at the NMPS Project. The upper limit in the upper reservoir will be increased by 4.0 feet and the lower limit will be decreased by 18 feet for the December 2014-March 2015, period. The usable storage in the upper reservoir will be increased from 12,318 to 15,327 acre-feet, a change of 3,009 acre-feet, which represents 1,990 MWh of additional generation (for a total of 10,465 MWh). The number of hours at full load generation will be increased from 7.4 to 9.2 hours. The additional capacity can be replenished with approximately three hours of pumping to the upper reservoir.

FirstLight is a subsidiary of GDF SUEZ North America.

A company contact is: John Howard, Director FERC Compliance, FirstLight Hydro Generating Co., Northfield Mountain Station, 99 Millers Falls Road, Northfield, MA 01360, Tel: (413) 659-4489, Email:

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.