Thursday, February 24, 2005

sustainable methane

Hydroelectric power's dirty secret revealed

...resulting in a build-up of dissolved methane. This is released into the atmosphere when water passes through the dam's turbines. (...) In effect man-made reservoirs convert carbon dioxide in the atmosphere into methane. This is significant because methane's effect on global warming is 21 times stronger than carbon dioxide's.

In practical terms, I read that as: we must extract this methane and burn it. Post peak, the carbon released from using this particular and limited source (dammed water) should be sustainable within the carbon cycle. Overall emissions will be dropping.


At 1:32 AM, February 25, 2005, Blogger Big Gav said...

While I've seen people extracting methane from coal seams and landfills (and generating power using it), I'm not sure how you'd extract methane from a dam - got any suggestions ?

I think this article should be viewed in context - maybe Brazilian dams generate methane, but I'm not sure that that wouldn't have happened anyway if the dams weren't there.

Most other dams that aren't fed out of rainforests probably have far less organic matter in them and therefore pose much less of a problem...

At 1:46 AM, February 25, 2005, Blogger monkeygrinder said...

This methane is in the water at the bottom of the dammed up artificial lake, and could probably be pumped out and seperated.

All lakes have this methane - not every lake has a potential exit point for methane saturated water.

I am honestly just speculating right now - this is the first I've ever heard of this.

At 5:35 AM, February 25, 2005, Blogger Big Gav said...

Of course, I'm just speculating as well, but the impression I got was that the methane came from the rotting vegetation (organic matter) that flowed into the lake.

So if your dam is in a location that doesn't trap much vegetation (glacier fed rivers flowing into dams through lightly or unforested areas, for example), then I'd expect little methane in the waters.

So my point is that a Brazilian dam may not be a typical example - but I'm no expert on what an average dam is, so maybe I'm talking nonsense.


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