COG objecting to expansion of Northfield Mountain reservoir storage capacity

Last modified: 12/31/2015 6:55:35 PM
NORTHFIELD — Two regional organizations are objecting to a proposal for the Northfield Mountain hydroelectric station to pump and release 25 percent more Connecticut River water over the next several months to generate more electricity for the region.

With just weeks remaining before proposed changes at Northfield Mountain Pumped Storage Project are planned to take effect, the Franklin Regional Council of Governments has formally objected to the proposal to expand use of the power plant’s mountaintop reservoir.

And Greenfield-based Connecticut River Watershed Council, a nonprofit environmental organization, has filed to intervene in the proposed license amendment pending before the Federal Energy Regulatory Commission, which controls how power plants like Northfield Mountain. Both COG and the Watershed Council have raised concerns about data Northfield Mountain’s owners used to argue that adding storage capacity to the plant’s reservoir in the past has not hurt the Connecticut River.

FirstLight Hydro Generating Co.’s application in September to change its operating license temporarily as of Dec. 1 calls for allowing an additional 22 feet of pumping capacity to its 5-billion-gallon reservoir through March 31 so the region can have additional power to compensate for closed generators like Vermont Yankee.

The underground pumped-storage power plant, which uses Connecticut River water pumped up the mountain overnight, when electricity prices are lowest, and releases it when there is peak demand and prices are highest, can provide quick startup for the region’s electricity grid, going from standby to 1,143 megawatts in six to eight minutes.

Raising the reservoir’s upper limit by 4 feet and its lower limit 18 feet increases its storage capacity by nearly 25 percent, translates to an additional 1,990 megawatt hours of generation, according to the filing.

ISO-New England, the Holyoke-based independent system operator of the region’s electric grid, has written to FERC in support of the license amendment application, agreeing with FirstLight that the change would provide ISO-NE “with additional resources to address winter reliability needs, with no adverse impact.”

The increased operating flexibility of an expanded reservoir limit would not require any changes to the existing Northfield project, FirstLight says in its application, since the upper reservoir was constructed to accommodate the water elevation the company is seeking. There would also be no change in the hydraulic capacity of its pump-turbines and no change in Northfield Mountain’s maximum generating capacity or maximum pumping capacity and no change in the existing maximum and minimum elevation limits established for the 22-mile-long river stretching that serves as its lower reservoir.

John Howard, FirstLight Hydro’s director of FERC compliance, told The Recorder in October, “The U.S. Fish & Wildlife Service, the National Marine Fisheries Service, the Massachusetts Division of Fisheries & Wildlife and the Massachusetts Department of Environmental Protection have reviewed a draft of the application with no objections” and that there are no reports of any observed environmental effects due to modified project operations last winter.

But FirstLight’s argument that it hasn’t found or received any reports of observed environmental effects due to modified project operations in the past is called into question by both the COG and the watershed council.

In an Oct. 29 letter to FERC, COG Land Use and Natural Resources Program Manager Kimberly Noake MacPhee, as staff to its multi-agency Connecticut River Streambank Erosion Committee, argues that trying to extrapolate from short-term data is invalid, and that the way the surveys of river sections are done don’t give a true indication of whether there have been environmental effects.

“They’re really asking for a lot without backing up their claim,” Noake MacPhee said. “It’s important to make sure they’re taking a close look at what’s happening to the river.”

The concern about proposed operational changes is their effect on bank stability in the 20-mile river stretch upstream from Turners Falls because of more frequent, larger river elevation changes from the pumping.

Increased pumping has been allowed temporarily on a short-term basis, but the COG and the Watershed Council have raised concerns about such protocols eventually being incorporated into the long-term operating regimen for the plant, which is up for relicensing.

“Banks tend to become unstable over a period of time, but the changes to the bank profile can be sudden and severe, with large sections of bank sliding, slumping or falling into the river,” says the COG’s letter. “Limiting the analysis to a six-month period (with surveys in September 2014 and June 2015) is not helpful in evaluating the potential environmental impacts of operational changes during the 2014/2015 temporary amendment.”

Instead, it calls for data during license amendments in 2001, 2005, 2006, and last winter, as well as in “typical winters, such as 2002-2004 or 2007-2013. It also asks that FirstLight’s data be presented on a scale “more reasonable for analysis and interpretation with respect to bank stability.

The Watershed Council, in its Oct. 29 request to intervene in the case FERC has been asked to decide by Nov. 27, notes the arguments that the region needs additional reliable generating capability this winter because of the retirement of Vermont Yankee and other power plants.

But the organization adds in its application that it “disagrees that FirstLight has adequately demonstrated no adverse environmental impacts from the proposed license amendment. FirstLight has provided flawed information and has withheld other information concerning river and bank conditions from last year’s temporary amendment. We also disagree that the license amendment is necessarily in the public interest for the entire term of the existing license.”

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