Letter to the Editor: How science actually works

4 mins read

Peer review is meant to keep lawmakers and scientists honest. We don’t assume they’re without flaw, so construct systems to ensure their flaws don’t harm us.

Bradford Hager bypassed that process when he testified before the Army Corps of Engineers. MIT, Oak Ridge National Laboratory, and others are attempting to undo the damage he did by releasing peer reviewed studies of their own that show hydroelectric reservoirs are not as easily characterized as agents of warming as Hager would have you believe.

MIT’s Center for Energy and Environmental Policy Research released the first in May 2021 as the testimony Hager provided was beginning to influence energy and environmental policy here in Maine. It was titled, ‘The role of hydropower reservoirs in deep decarbonation’. In it researchers argued that a 2-way transmission line between New England and Quebec could offset fossil fuels consumption regionally by sending hydropower to New England when solar and wind assets are not effective and sending excess solar and wind derived energy to Quebec when they are.

Unlike Hager, they present a position that is supported by a plethora of literature. That’s what’s necessary to pass peer review. You can’t rely on one study as Hager did, taking one group’s formula for estimating methane emissions from hydroelectric reservoirs and assuming it will produce a more accurate estimate than direct sampling does. What MIT found is that the data currently available does not allow scientists to accurately predict methane emissions at a given plant because there are simply too many variables to consider.

Last month Oak Ridge National Laboratory released a study that revealed the problem is even more complicated. It’s titled, ‘Getting lost tracking the carbon footprint of hydropower ‘. In it researchers argue that reservoirs may release a lot of methane and still reduce warming. That’s because they also hold carbon that’s washed into them from upstream. They suggest the only way to truly know if a reservoir releases more greenhouse gas than it suspends is to know how much carbon enters the reservoir. If the warming potential of that carbon is greater than the warming potential of the greenhouse gases released, then the reservoir acts as a cooling agent.

What that study reveals is that greenhouse gas per unit energy produced (the measure Hager used to argue Quebec’s hydro reservoirs are warming) is less important than the ratio of greenhouse gas emitted to carbon captured is. They found no statistical difference between reservoirs that produce electricity and those that do not. In other words, they found that there’s no evidence to support the belief that reservoir removal is necessarily good or bad where climate impact is concerned. A reservoir’s role in the watershed must be better understood to do that.

What those and other researchers are arguing is that these decisions must rely on a close examination of the watershed in question, on direct examination not predictions as Hager argued. They find that we do not currently have enough data on reservoirs to rely on estimates produced by the mathematical formulas any researcher has developed to do this so far. That’s a complicated way of saying the best we can do so far is what researchers studying Quebec’s reservoirs directly have done so far.

Jamie Beaulieu

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