The Dirty Truth About Hydropower
by Eric Kane, New York, NY on 11.16.06
Although large-scale hydroelectric facilities fail to qualify under most definitions of renewable energy, hydropower is generally agreed to be a relatively low carbon intensity form of electricity generation. However, a recent report by the International Rivers Network may change the collective perception of hydroelectricity, in particular tropical hydropower. According to ‘Battling Over Bubbles: Big Hydro Hides its Role in Global Warming’, “tropical hydropower reservoirs can have a greater impact on global warming than even their dirtiest fossil fuel plant rivals”.
The report indicates that the greenhouse gases in question, carbon dioxide and methane, are emitted from the rotting of flooded vegetation and other organic matter that is present in hydroelectric reservoirs. The release of water at a dam is subsequently compared to the opening of a “vast coke bottle”. More specifically, the report suggests that as water is released from turbines there is an associated large and sudden release of gas bubbles. This has led some to estimate that “in 1990 hydropower dams in the Amazon caused between 3 and 54 times more global warming than modern natural gas plants generating the same amount of energy”.
Needless to say, this and other similar reports have generated denial on the part of hydro industry-backed researchers. As a result, the International Rivers Network is calling on the United Nations and the Intergovernmental Panel on Climate Change to develop more definitive research on this topic. This issue is of particular concern as hundreds of millions of dollars in climate subsidies and carbon credits could be spent on hydroelectric projects, which might actually serve to intensify global warming while also destroying ecosystems.
Begging to differ here on this notion. By whose definition is hydropower non-renewable? Every drop of water that passes through a turbine is there because of the sun.
The cited study ignores a basic understanding of the earth's suface water phemonena. Reservoirs, and all lakes for that matter, in the northern temperate zone (US and Canada for instance) are too cold and oxygen rich for most of the year for anaerobic decomposition to make the methane budget go negative. This is why logs that sunk to the bottom of northern lakes during the clear-cutting days of the 1800's are still there! The opposite is generally true of tropical and subtropical water bodies. Let's be careful not to make generalizations that clearly do not apply by any rational measure to norther hydro projects.
I have not done any far range analysis on this. But if I was researching this my initial hypothesis would be.
"The water is not in an isolated system. The water will be in a state to readily be carbonated."
Though as always, auditing of these industries, and having better metrics may result in a much "cleaner" approach to the "environment."
That is a pathetic report. 4 - 54 times as much as a modern Gas powered plant! Gas powered plants are very clean and are typically used close or even in residential areas. How dare the author twist the fact by calling it
"Dirty truth about..."
Besides, it's not true. Yes, flooded vegetation will rot and emit some carbon gasses and so do I when I fart but only until it is gone. Maybe they should burn the area clean first? Hydro Power plants keep operating well after those few scrubs have rotted away. What a stupid biased report.
It's not carbon gas that farts and rotting wood emit, it's methane, 23 times more of a green house gas than carbon dioxide.
Interesting... I'm sorta skeptical of exactly how bad hydro really is, aside from the asthetic concerns of flooding many acres.
What puzzles me is - I'm not a fan of clear cut logging, but if there's ever a case for it, this is it. If all this forest is going to be flooded anyway, then why not log it and put the wood to decent use? Especially if there's a carbon issue?
I lived in Duluth, Minnesota for a few years and was pretty involved in a campaign/lobby effort to stop the expansion of a nuclear power plant. The cheap alternative was water generated by Hydro-electric systems in Manitoba to the North; a project that was also pushing for expansion. Here's a great little video on the cultural impacts of Hydro-electric dams in Cree communities supplying cheap power to Minnesota:
green green water trailer
From what I understand, local fisheries where devastated and these dams came with a heavy price for the surrounding communities. You can see why:
some pics
It's more of a methane issue I thought. It's 23 times more a green house gas than carbon dioxide.
This is my 3rd or 4th post here and none are making it.
If this is true, the gas released can be captured and used as fuel as it's going over and or through the dam! Pretty cool.
Bring on the studies, I'll work on the alternate fuel plant at the dam project.