Pumped storage hydro in Maine

Could a large pumped storage hydroelectric facility be developed in Maine? A company named Western Maine Energy Storage, LLC has applied to federal hydropower regulators for a preliminary permit to evaluate the potential development of a 500 megawatt pumped storage facility above the Androscoggin River in the Dixfield area.

Historically electricity has been easier to generate than to store. Hydropower typically harvests energy from water flowing or falling downhill under gravity's influence. If water in a hydroelectric system can be pumped back uphill, it can be stored in an upper reservoir and then reused to generate additional electricity. This technology was first used in Europe in the late nineteenth century, and remains the dominant form of electric energy storage today. Pumped storage hydropower facilities presently account for nearly all of the utility-scale energy storage capacity in the U.S.: about 96% as recently as 2023.

Modern pumped storage hydropower plants typically move water between an upper reservoir and a lower reservoir, using lower-cost electricity for the uphill pumping phase of the cycle. Pumping water uphill to recharge an upper reservoir takes energy, but most of this energy can be recovered on demand by allowing the water to flow back downhill through the generators. According to the Federal Energy Regulatory Commission, several dozen pumped storage projects are constructed and in operation in the U.S., with a total installed capacity of over 16,500 megawatts.

As part of the ongoing energy transition, many policymakers and investors are focused on technologies like battery energy storage, but pumped storage hydropower has a long track record of success -- and significant potential for growth. Most pumped storage generators in the U.S. were built during the 1970s, but a 2016 report by the U.S. Department of Energy found that the US could add 36 gigawatts of pumped storage by 2050.

Western Maine Energy Storage's application to the Federal Energy Regulatory Commission describes a proposed project located primarily in Dixfield, Maine (with a portion in the adjacent town of Canton). The upper reservoir would be located just below the crest of Colonel Holman Mountain; the lower reservoir would be in the adjacent Ludden Brook watershed. The project would draw its initial fill water from the Androscoggin River at a site near the Dixfield-Canton boundary (delivered via a temporary 2-mile pipe), but would then shift to closed-loop operation (using groundwater wells for reservoir level maintenance). The project would have about 500 MW of generating capacity (two units of about 200-250 MW each). The applicant says it expects to spend about $6 million studying the project’s feasibility if FERC grants it a 48-month preliminary permit. 

Maine is not presently home to any pumped storage hydropower projects, but about 90 years ago the Passamaquoddy Tidal Power Project was proposed with features including pumped storage reservoirs and generators. The Quoddy project would have used tidal energy and pumping to transfer water uphill, to produce sustainable renewable energy. The project received significant support from President Franklin D. Roosevelt along with millions of dollars in funding from Congress, but was never completed. To learn more about the historic Passamaquoddy Tidal Power Project, read the book Moondoggle: Franklin Roosevelt and the Fight for Tidal-Electric Power at Passamaquoddy Bay by Mark C. Borton.