CLF has been asking questions about the carbon footprint of large-scale Canadian hydropower since before the Northern Pass project’s inception. I recently raised our concerns in my list of three ugly numbers behind the regional push for more hydropower imports, pointing out that, in the first decade after flooding, greenhouse gas pollution from new hydropower reservoirs can produce 70% as much greenhouse gas pollution as natural gas power plants, according to Hydro-Québec’s own science.
As with our number on new hydropower costs, Hydro-Québec took exception in a press release, asserting that CLF does not understand the science. We obviously disagree. In this post, the second in a series of three, I will break down what Hydro-Québec’s defense of its product gets wrong—on the climate benefits of its hydropower. This will be a deep dive, especially because Hydro-Québec’s press release is so profoundly misleading.
Why CLF Cares About Hydropower’s Carbon Footprint
Why is this issue important at all? As our region considers massive new infrastructure to import more hydropower, we need to have a full, honest accounting of the real impacts—on both sides of the border. Greenhouse gas pollution and climate change know no international boundaries, and New England is ultimately responsible for the carbon pollution attributable to its power use.
Getting credible estimates of the climate effects of new imports is especially important because virtually every proponent of new hydropower imports touts reduced emissions as a dominant reason to pursue them. Likewise, federal law and some state statutes require accurate assessments of what new imports of hydropower will mean for New England’s greenhouse gas emissions and how we achieve our short-term and long-term climate goals. To the extent new imports are in the region’s future, something CLF could support with the right conditions, we need honest numbers.
Given that hydropower projects do not have smoke stacks, when I say “carbon pollution” or “greenhouse gas emissions” from hydropower, what do I mean? Reservoirs behind new dams inundate vast geographic areas. For example, the Eastmain reservoir in the James Bay region is roughly 600 square kilometers, or more than three Lake Winnipesaukees. Drowned vegetation and biological material decompose over time and release carbon dioxide and methane into the water column and then into the atmosphere. In addition, the flooding destroys northern forested landscapes that can be potent carbon sinks (and are often called “lungs of the planet”), increasing the net greenhouse gas emissions of the reservoir by the amount of any lost capability to sequester carbon.
The key question is how much net greenhouse gas pollution a reservoir produces for its power output over time. To assess the climate effects of new imports of hydropower, pollution from the facilities supplying the power can be compared with the emissions of displaced power here in New England.
It’s also important to understand the effects in the province supplying the power and in neighboring regions, like New York or Ontario. If Canadian hydropower is merely shifted from those markets to ours and the gap is filled by fossil fuel power plants, the imports won’t reduce greenhouse gas emissions overall.
What Hydro-Québec Gets Wrong About Its Own Research
In its press release, Hydro-Québec says that “CLF asserts that hydropower greenhouse gas (GHG) emissions are much higher than they actually are … by cherry-picking data contained in a scientific study on emissions from a recently created reservoir in Québec…. What that study really indicates is that hydropower is one of the lowest-emission generating options per kilowatthour produced.”
Here again, as with hydropower costs, Hydro-Québec misstates CLF’s point. The number I cited does not pretend to describe all hydropower, or even all Hydro-Québec hydropower.
The 70% number clearly and expressly describes the emissions from a new large-scale hydropower facility during the first ten years of operation. It is taken directly from peer-reviewed scientific analysis by Hydro-Québec and academic researchers of data collected at the Eastmain 1 reservoir, a new hydropower facility in northern Québec. My blog post includes the relevant graph, presented in a scientific paper that a Hydro-Québec scientist co-authored, showing a direct comparison of these emissions with natural gas and supporting CLF’s statement that a new large-scale hydropower facility can emit 70% of the greenhouse gases of natural gas power plants in the decade following development.
A 100-year life-cycle analysis shows lower long-term emissions, but in a world where climate change is accelerating and we desperately need to reduce emissions now, the early emissions of Hydro-Quebec’s new facilities—several of which are under construction and slated for development in the coming few years—are vitally important. Moreover, it is these new facilities that Hydro-Québec intends to rely on to support new exports to the United States, likely making their carbon footprint more relevant to New England’s current decisions to increase imports than the footprints of existing reservoirs that are supplying Québec customers.
It is worth noting that the 100-year emissions described in the research are much higher than the numbers that Hydro-Quebec’s press release implies that the study confirms. The paper says that 100-year emissions are 40% of the emissions of natural gas power plants, about ten times more than the factor Hydro-Québec quotes and much higher than solar and wind power, which emit no pollution once installed.
While Hydro-Québec says CLF is “cherry-picking” a data point from its research, it ignores that the data point is a key finding of what is now seminal research, which Hydro-Quebec touts on its website as the first time ever that researchers have measured the emissions of a landscape developed for hydropower both before and after flooding:
Project EM-1 is a world first, since this is the first time that GHG emissions are measured before and after the creation of a hydroelectric reservoir. This will make it possible to precisely identify the impact hydroelectric reservoirs have on greenhouse gases.
Despite its billing, Hydro-Québec’s Eastmain research does not provide a full picture. In particular, there are many important differences between hydropower facilities in Québec, and the differences’ effects on reservoir emissions haven’t been fully researched.
For example, Hydro-Québec’s new dams along the Romaine River, now under construction, are creating somewhat smaller reservoirs than Eastmain (collectively, only one and a half Lake Winnipesaukees), suggesting that they might produce less net pollution. However, the flooded landscape along the Romaine and the flooded landscape at Eastmain are quite different. Hydro-Québec’s research at Eastmain suggests that the flooded landscape wasn’t a carbon sink prior to reservoir construction, whereas the landscape along the Romaine is more heavily forested and could provide much more vegetation that will decompose over time as well as a greater value as a carbon sink, which is now being lost.
And of course, the project’s emissions rate depends on how much power the reservoir produces. A vast reservoir that produces a relatively small number of megawatts of power will likely have a higher emissions rate than a smaller reservoir in the same landscape that produces a higher number of megawatts. That’s why true “run-of-river” hydropower facilities, which are powered by the flows in existing rivers and do not require enormous dams or flooding, are much lower carbon resources than large-scale hydropower.
Hydro-Québec’s Faulty Math
So why is Hydro-Québec so upset with CLF’s characterization of the utility’s own groundbreaking research? The core of Hydro-Québec’s disagreement with CLF is this: the utility likes to cite a greenhouse gas emission rate (pollution per unit of energy generated) that assumes its Eastmain reservoir alone powers two generation stations (meaning that the emission rate equals the reservoir’s emissions divided by the output of both stations). When the utility is in charge of the presentation, it highlights this number, which reflects a steep drop in the emission rate after the newer generation station came online by early 2012. The peer-reviewed version of the research, published in 2012, refuses to make that assumption and leaves out the newer generation station from the reservoir’s power output. Why?
The new station (Eastmain 1-A) was constructed to include flows made possible and channeled to the Eastmain reservoir by Hydro-Québec’s massive project to divert the Rupert River. That means that the net effects of the landscape changes associated with the diversion project are key to understanding the emissions of the Eastmain complex as a whole. A major element of the diversion project was the creation of two diversion bays totaling about 350 square kilometers, or the flooding of about two additional Lake Winnepauskees. While Hydro-Québec’s favored number assumes that this flooding has no net effect on emissions, the peer-reviewed research says the effects are unknown and therefore does not include the power from Eastmain 1-A in its calculation of the Eastmain emission rate.
That leaves us with the table from the peer-reviewed paper itself, which is where CLF got its number. We are also informed by the thorough research summary from Synapse Energy Economics on this topic that CLF released more than two years ago, which shows that new hydropower facilities have significantly higher emissions than have been assumed and advertised.
CLF has attempted to engage Hydro-Québec in a serious dialogue on this issue. While there have been several interactions—like this one on our blog after CLF released the Synapse report—we have yet to see anything that meaningfully addresses CLF’s concerns or corrects its misleading public relations campaign.
The Need for Honest Numbers
If this all seems complicated to you, you’re right. The research on hydropower emissions is not complete, and it is probably fair to assume there is significant variation from reservoir to reservoir. Some likely have a larger carbon footprint than Eastmain and some smaller; some are decades old, with relatively low emissions going forward, and others are newer, with a larger carbon footprint now and in the near term.
For many years, policymakers and large-scale hydropower boosters have assumed this complexity away. Hydropower emissions were either presumed to be zero or were pegged at a level based on extrapolations from simple measurements of greenhouse gas emissions from reservoir surfaces, including reservoirs flooded many decades ago. In many cases, including in Canada’s inventory of greenhouse gas emissions, a single miniscule emissions figure is used to characterize all large-scale hydropower facilities. These assumptions are at work in Hydro-Québec’s press release, including in its comparisons to other power sources and its statements about avoided emissions from its energy sales.
We know now that the old simplifying assumptions can be way off, which is one reason why CLF and others have identified a need to “tag” the energy from individual power facilities in Québec that are used for exports to the United States and define, with at least some reasonable approximation, the energy’s source and its environmental attributes and emissions profile.
The developers of the Northern Pass transmission project and Hydro-Québec are continuing their campaign to gloss over the very real greenhouse gas pollution that hydropower projects create. Despite Hydro-Québec’s own research, they are advertising numbers and slogans that inaccurately minimize reservoir carbon footprints or deny the pollution even exists. Unfortunately, it’s also the case that many New England policymakers and the federal officials reviewing Northern Pass’s permit application appear thoroughly disinterested in getting to the bottom of what Canadian hydropower projects really mean for the climate or in insisting on an accurate accounting from Hydro-Québec. For example, we have not received a single substantive response to our August 2013 request that the states meaningfully assess this issue as part of their regional efforts around hydropower imports.
As with the costs of Canadian hydropower, New England deserves honest information about the emissions of the product that Hydro-Québec wants to sell us. Instead of impugning CLF for raising questions, Hydro-Québec and American transmission developers like Northern Pass that want to bring New England its power should start offering New England the basic respect of fair dealing and real numbers.
Coming next in this series, what Hydro-Québec’s defense of its product gets wrong—on the reliability benefits of new imports for the New England electric grid.