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PUMPED STORAGE AND ITS ROLE IN THE GRID   

What is Pumped Storage?

A pumped storage facility is a means of storing energy in the form of water that has been pumped to an upper reservoir.  This water can be released when needed to run turbines to generate electricity. This much is good, because it makes clean, hydroelectric power that can be generated when needed, acting like a giant battery.

However, all energy storage systems lose energy during the process, and pumped storage facilities are no exception.  They take more energy to pump water to the top than they generate when the water comes back down.  About 20 – 30% of the energy is lost.

Although that sounds intuitively like a bad idea, there are times when this storage capacity is worth it (more below).  They pump water up when electric demand is low  (mostly at night when electric prices are cheaper), and let it out when there is peak demand (and prices are higher, like a summer afternoon when the whole world wants to run air conditioners).

How is the Northfield Mountain Pumped Storage Facility  different than most?

All pumped storage systems need an upper and a lower reservoir.  Northfield Mountain has an upper reservoir, where the top of the mountain was dug out to make a lake.  However, instead of a human-made lake for the lower reservoir, Northfield Mountain / FirstLight uses the Connecticut River that has been backed up for miles by the Turners Falls Dam.  This is called the “impoundment area” and it goes upstream from the dam, through Barton Cove, all the way to the dam at the Vernon VT hydro project.   (Great River Hydro owns that facility, also up for FERC re-licensing.)

So why / how is that a problem?

Greening Greenfield believes the issues with the Northfield Mountain Pumped Storage facility fall into 2 basic categories:

  • Fossil Fuel Used:  The fact that the energy used to pump water up comes from the MA utility grid, the majority of which is generated from fossil fuels at this time.  Thus the produced hydro energy should not be claimed to be “clean, renewable energy”.
  • Environmental Impact on the River:  There are numerous environmental impacts that result from using the Connecticut River as a lower reservoir.  These include issues of flow – too much and too little – causing erosion and allowing a nearly dry riverbed; and the effects on aquatic life of all sorts, including, but certainly not limited to adult fish.

Greening Greenfield will continue to advocate for changes to the operation that halt this ongoing destruction and repair damage already done.  GG also supports improved recreational opportunities, and increased sensitivity to the cultural history of the area and the past and current relationships of native populations with the river.

So why would anybody want Northfield Mountain at all, besides the owners to make money?

It is true that Northfield Mountain facility was originally built to complement the Vermont Yankee nuclear power plant operation.  Since nuclear facilities do not start and stop their operations, but keep running and generating electricity even when the demand is low, the excess power at night was used to pump water to the top of Northfield Mountain.  Vermont Yankee is now closed.

HOWEVER, the transition away from fossil fuels to renewable sources such as solar and wind energy requires energy storage. Wind doesn’t always blow at the same rate, and solar power varies depending on time of day, year and weather conditions.  But people use electricity regardless of those facts.

Storage could be from batteries, but existing batteries use toxic materials and healthier possibilities are not available at scale yet.  Northfield Mountain can store a LOT of energy.  FirstLight’s website says it is the largest energy storage facility in New England.  Several of the offshore wind facilities off Cape Cod that are under construction or under consideration have partnered with FirstLight.  They have to show the ability to produce consistently for the grid.  Without Northfield Mountain, we probably won’t be able to get the wind power we need to transition away from fossil fuels. That doesn’t mean we want the Northfield Mountain facility operating in the way it has been.

If we don’t have storage such as this, then we’ll need more fossil fuel peaker plants like this gas one proposed to be built, brand new, in Peabody, MA. (5.33 minute video).

One other side note:  Northfield Mountain can make money by NOT making electricity, too.  They get paid to have the ability (a full upper reservoir) to generate electricity in case more traditional sources run into trouble from storms, equipment failure, etc.  FirstLight relies on Northfield Mountain to restart the electric grid if the grid goes down.  This is called a “black start”.