Latest Research: Northern Pass Worse for the Climate than Advertised

Christophe Courchesne

Hydro-Québec hydroelectric projects recently commissioned or under construction (Source: Quebec Ministry of Natural Resources and Wildlife)

Reducing the region’s emissions of greenhouse gases is supposedly the Northern Pass project’s marquee public benefit, its raison d’être as they say in Québec. But would the Northern Pass project do the job?

The answer appears to be: probably not any time soon. Today, CLF is releasing a ground-breaking new technical report regarding the greenhouse gas emissions of Canadian hydropower. The conclusions of the report show that large-scale hydropower, especially new reservoirs, is worse for the climate than Northern Pass’s developers are claiming, with substantial greenhouse gas emissions that are comparable to those of modern natural gas-fired power plants. The current Northern Pass proposal substitutes hydropower for natural gas in New England’s energy mix, meaning that the project won’t reduce emissions by much if any, especially in the near term.

Authored by Synapse Energy Economics, the technical report released today, Hydropower Greenhouse Gas Emissions: State of the Research, is an independent survey of the recent science regarding the greenhouse gas emissions of hydropower. The science is clear that the reservoirs behind hydropower dams emit greenhouse gases, relative to the forests and wetlands they flood (which often take greenhouse gases out of the atmosphere). Overall, reservoirs in Québec emit more greenhouse gases over the course of their lives than renewables like wind, solar, and run of river hydropower.

A crucial finding of the report concerns new reservoirs. In the first several years after a reservoir is dammed, large amounts of newly inundated organic material decompose, emitting carbon dioxide that diffuses through the water into the atmosphere. As a result, a reservoir’s net emissions in its early years are very high – starting out even higher than emissions from a natural gas power plant per unit of power generated. This effect is evident in recent, rigorous analyses by several teams of scientists, based on data collected at Hydro-Québec’s Eastmain 1 reservoir in northern Québec. This reservoir is the very same project that Northeast Utilities’ CFO testified under oath last year would be the primary, if not exclusive, source of Northern Pass’s power. Even when their emissions are projected over their lifetimes, newly flooded Canadian reservoirs may emit nearly two-thirds of the greenhouse gases emitted by natural gas power plants. By contrast, reservoirs emit only about 20% of the greenhouse gases emitted by typical coal-fired power plants.

This conclusion is the death knell for Northern Pass Transmission, LLC’s (NPT) claim that the current Northern Pass proposal would reduce greenhouse gas emissions by up to 5 million tons. We explained the claim’s key flaw – the report on which it is based erroneously assumes that hydropower has no greenhouse gas emissions – back in August. In light of today’s report, CLF is calling on NPT and its partners NU, NSTAR, and PSNH to stop citing that erroneous number and to withdraw all marketing materials for the Northern Pass project that state or imply that Canadian hydropower has no or minimal greenhouse gas emissions. Hydro-Québec is building new hydropower projects that are intended to facilitate new exports to the northeastern United States. To the extent that the prospect of exports is driving the construction of new reservoirs, Northern Pass and projects like it will be responsible for those reservoirs’ emissions and also their other adverse environmental impacts. And if, as the developers’ analysis concluded, the power to be displaced by imports through Northern Pass is overwhelmingly from natural gas plants, the emissions from a succession of new reservoirs in Canada may replace – perhaps completely for a period of time – the emissions of displaced natural gas power. In that scenario, the Northern Pass project would do little – or even nothing – to reduce greenhouse gas emissions, at least in the near-term.

The report makes another critical point about a different kind of displacement that could occur with Northern Pass. According to a recent study, stepping up Hydro-Québec’s exports to the United States may actually decrease its exports to other provinces in Canada, where the need for fossil fuel-fired power then increases, resulting in additional emissions. Those emissions may cancel out any reductions from displaced power in the United States. This effect is a potential blind spot that needs to be considered and analyzed as part of the public review of any new imports.

The report’s findings are important information regarding the environmental impacts of the project that the U.S. Department of Energy must consider as part of its review of Northern Pass’s application for a Presidential Permit. For that reason, earlier today, CLF submitted the report to DOE along with Synapse’s analysis of the potential effect of Northern Pass on the regional market for renewable energy.

To CLF, the report suggests that new imports could be part of the region’s climate strategy if imports:

  • displace dirty power, like project sponsor PSNH’s uneconomic, subsidized power plants, to achieve a meaningful net reduction in greenhouse gas emissions without increasing the use of fossil fuel-fired power plants in Canada;
  • support – rather than undermine – local renewable projects and energy efficiency efforts in New England; and
  • have minimal impacts on the environment and communities on both sides of the border.

PSNH is in a unique position to take its coal units offline, in conjunction with its potential power purchase agreement with Hydro-Québec that is supposedly in the works. Instead, PSNH is marching on with its broken coal-based business model at great cost to New Hampshire consumers and the environment. Unless the proposal changes, the Northern Pass project does not deliver on the developers’ claims and will not advance a cleaner energy future for New England.

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