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MIT study: Quebec hydro reservoirs provide valuable energy storage for U.S. northeast

Transmission Line

States in the northeastern U.S. can transition to low-carbon electricity at a lower cost by using hydropower reservoirs in Quebec, Canada, for energy storage, says a new MIT study. The study argues that Quebec’s hydropower reservoirs are best seen by northeastern states as a virtual energy storage resource rather than a continuous energy source.

In a low-carbon future, the value of Quebec hydropower is maximized when used to balance and store renewable electricity generated from variable U.S. wind and solar resources. Adding cross-border transmission lines can facilitate the two-way power flows needed to leverage these benefits further, MIT says.

As more U.S. states commit to 100% clean electricity or net-zero emissions, power generation will increasingly rely on renewable technologies such as wind and solar photovoltaic. Because these technologies are intermittent and cannot be dispatched as needed, they require a backup source to ensure stability of the electricity system across hours, days and seasons.

Hydropower reservoirs in Quebec offer a potential backup source for this variable generation in the U.S. What’s more, by importing energy from the U.S., Quebec can accumulate additional energy in its reservoirs to release when wind and solar energy in the U.S. is scarce. Currently, however, hydropower is seen as a source of continuous generation, substituting for clean energy in the U.S. 

Instead, using a capacity expansion and dispatch model to simulate a power system covering New England, New York and Quebec, researchers at the MIT Center for Energy and Environmental Policy Research show that two-way trading between the U.S. northeast and Quebec can help reduce overall power system costs, decrease dependence on natural gas in the U.S., and lower the need for carbon capture and sequestration in a decarbonized electricity system.

For this scenario to play out, use of hydroelectric generation and transmission assets has to shift away from one-way electricity exports from Canada to the U.S. and instead needs to facilitate two-way trading of electricity.

Constraints in cross-border transmission capacity also limit the ability of northeastern states and Quebec to benefit from trading. As the study shows, expanding transmission lines between Canada and the U.S. can substantially decrease power system costs. The authors estimate that the addition of 4 GW of new transmission between New England and Quebec would lower the costs of a zero-carbon electricity system in these regions by 17% to 28%. The study also finds that the existing hydropower resource is sufficient to provide these balancing services to the northeast without necessitating new hydropower reservoirs.