My motivation in posting this is to remind people of something I think they should know. Electrical power produced by hydroelectric dams isn’t green. From Science Magazine a couple of years ago:
Using rivers and dams to make electricity is often touted as a win for the climate, a renewable source of electricity without the greenhouse gases that come from burning fossil fuels. But it turns out hydropower isn’t quite so squeaky clean—and with countries around the world poised to erect hundreds of new dams, that could have big implications for future emissions.
Reservoirs already contribute roughly 1.3% of the world’s annual human-caused greenhouse gas emissions, the study finds—about as much as the entire nation of Canada. It also suggests future reservoirs will have a bigger impact than expected, largely because they emit much more methane, a potent warming gas, than once believed. The methane is produced by underwater microbes that feast on the organic matter that piles up in the lake sediments trapped by dams.
There is plenty of research on methane emissions from hydroelectric dams, upstream behind the dam as well as downstream from the dam. Methane is significantly worse than carbon dioxide in terms of the greenhouse effect. From Scientific American:
While CO2 persists in the atmosphere for centuries, or even millennia, methane warms the planet on steroids for a decade or two before decaying to CO2.
In those short decades, methane warms the planet by 86 times as much as CO2, according to the Intergovernmental Panel on Climate Change.
But policymakers typically ignore methane’s warming potential over 20 years (GWP20) when assembling a nation’s emissions inventory. Instead, they stretch out methane’s warming impacts over a century, which makes the gas appear more benign than it is, experts said. The 100-year warming potential (GWP100) of methane is 34, according to the IPCC.
The bottom line here is that if you’re trying to reduce climate change due to greenhouse gases in the atmosphere building hydroelectric dams is probably no solution and may even aggravate the problem you’re trying to solve.
Interesting that the “global scientific consensus”didn’t notice that.
Kinda makes you wonder about their agenda.
They should be asking engineers.
Engineers deal with reality and hard numbers. Can’t have that when your job is to save the universe, no matter the cost.
The scientific consensus has known for years that reservoirs produce methane. Now they know they produce more than thought. That is why scientists keep studying stuff and altering their numbers (not because it is a conspiracy as is claimed by those on the right). As I am reading this it doesn’t mean that hydroelectric is necessarily a net warming cause, but rather that they, like everything else, should be looked at in comparison to the alternatives as in some cases they might cause more warming. Siting will become more important.
Steve
I completely agree with that. It’s why I think that “Build hydroelectric dams!” is an inappropriate strategy. The strategy should be “Build hydroelectric dams where appropriate”.
The best intelligence right now is that it takes between 4 and 7 years to build a hydroelectric power station. Assume it takes 2 years for the environmental studies and licensing. The lead time alone suggests that if your plan is a ten year plan, hydro probably does not play a leading role in it.
Just to be clear, I’m a hydro skeptic. I think that anyone but a dilettante recognizes that if your objective is reduction of greenhouse gases in the atmosphere that nuclear power and carbon capture have roles to play. I also think that U. S. deindustrialization is a terrible economic policy but that’s a topic for another post. Suffice it to say that moving your industrial production to China does not result in a net decrease in carbon emissions.
Pretty sure we didn’t move our factories there to cut our emissions. They went there so that the people running the companies or the owns who own most of them could make more money.
“Just to be clear, I’m a hydro skeptic.” Meh, for all we know this spurs some research to look at models other than dams with big reservoirs.
Steve
Mostly I wasn’t talking about us there but about the Europeans. They offshored a lot of manufacturing and then bragged about how they were cutting emissions. That was sophistry. In net terms it probably increased emissions. That’s why every so often I bitch about measuring results by sampling rather than tallying inputs.
A key example of that was revealed by the VW fraudulent emissions claims scandal. If VW’s emissions were bogus, how could that have reduced emissions? The answer is that they weren’t measuring their results they were calculating them based on expectations.
The manpower to do that doesn’t exist. It takes ten years to train the necessary folks. That means we need to pick our projects carefully. As I’ve been pointing out there are multiple limiting factors and money isn’t even the most important. The most important is management time, followed by professional resources. We can’t just open a new can of researchers.