NE’s largest battery
Rep. Roy took a trip to see New England’s largest battery and explore how it fits in the renewable energy ecosystem. Northfield Mountain is a pumped-storage hydroelectric plant and reservoir located on and under the mountain in Erving and Northfield, Massachusetts. In 1972 its 1,168 MW hydroelectric plant became operational as the largest such facility in the world (the Vineyard Wind project will produce 800 MW).
The man-made 300-acre upper reservoir, 800 feet above the Connecticut River, is capable of storing 5.6 billion gallons of water. Water from the reservoir flows through four 18-foot-diameter conduits drilled into the rock. Gravity and powerful pumps force the water down to the hydro plant carved into the mountain. The water spins the electric-generating turbines. To recharge the battery and get water back up to the mountaintop reservoir, the pumps work in reverse.
The underground powerhouse includes four large reversible turbines, each capable of pumping 27,000 gallons of water per second and generating 270,000 kilowatts of electricity. The powerhouse is accessible through a 2,500-foot-long tunnel. Seven hundred feet below the surface, the cavern is longer than a football field and higher than a ten-story building.