If Methane Emissions From Dams Are Counted, India's GHG Output 40% Higher Than Official Totals

[hatrack]

NEW DELHI - India's greenhouse gas emissions could be 40 percent higher than official estimates if methane released from dams is taken into account, according to a new study.

Methane -- about 23 times more powerful than carbon dioxide in terms of the amount of heat it traps -- is released from reservoirs, spillways and turbines of hydropower dams as a result of rotting carbon-containing vegetation.

But India, already one of the world's top polluters, has never measured methane emissions from its 4,500 large dams and has therefore never taken it into account in official data. According to a study by scientists from Brazil's National Institute for Space Research, methane equivalent of 825 million tonnes of carbon dioxide is released annually by India's dams.

"I am quite positive that surface methane emission estimations are correctly estimated," said Ivan B.T. Lima, lead author of "Methane Emissions from Large Dams as Renewable Energy Resources: A Developing Nation Perspective".

EDIT

http://www.planetark.org/dailynewsstory.cfm/newsid/42853/story.htm

[Gregorian]

1. This is total news to me.

Man, I've learned several things this week. One was regarding logging, and this. I never knew dams had methane emissions.

My guess is that methane emissions are short term. Decaying material only decays for so long, and then the methane gases cease. And then there is the alternative. I think hydroelectric is so far ahead of anything else, this isn't even an issue. Just a guess.

[razzleberry]

5. the organic matter behind the dam is continually replenished

'organic matter',
what in the west would be handled
by a sewage plant

[Dead_Parrot]

7. Have you run the figures for that?

To get Lima's figure, you'd need 625,265,215 people shitting pure carbon into the reservoirs every day. Even allowing for a high curry intake, that's pretty unlikely.

[AlecBGreen]

11. hmm

not all the methane is coming from rotting feces. Just like any fresh water system, these resevoirs are probably filling in with leaves, twigs, etc. They break down, release methane, and more comes in to replace it.

[whistle]

2. God, there must be a way to trap that methane gas to use as an energy source

...most sewage treatment plants in the U.S.A and I imagine other industrialized countries have done that for the last 50 years capturing as much methane as necessary to run the plants and all of there generators to be fully self sufficient for all their energy needs. Why can't a country like India apply that same technology to meet their requirements and save the environment as well. That's a no brainer...unless most other hydroelectric plants using dams ignore this methane pollution factor as well. In that case, the companies need to pay stiff fines.

[Eugene]

6. Sewage systems are mostly closed. Reservoirs and spillways are wide open.

Capturing methane from vegetation in open water
is not as easy as venting an enclosed tank.

[varun]

3. Methane from animal wastes

is used extensively in India as cooking gas.

[Dead_Parrot]

4. I'm not convinced...

For one thing "I am quite positive that surface methane emission estimations are correctly estimated" isn't quite as convincing as, I dunno, measuring the methane. And we're talking about a set quantity of biomass here: You can't say that much methane is released "annually" without some pretty fucked up math involving infinitely long farts.

[Dogmudgeon]

8. This is a REAL subject of concern

And there is a large body of work on the subject.

Yes, it was quite a surprise to me, too.

Simply running a Google search on "dams methane" or "hydroelectric methane" returns a large number of news reports and academic citations. This issue hasn't really registered yet with either the MSM or the environmental movement.

Adding "Lima" to the search spec shows that Ivan Lima is one of the experts in this field.

Here is one from two and a half years ago: Hydroelectric power's dirty secret revealed at New Scientist.

The green image of hydro power as a benign alternative to fossil fuels is false, says Éric Duchemin, a consultant for the Intergovernmental Panel on Climate Change (IPCC). "Everyone thinks hydro is very clean, but this is not the case," he says.


(In the event that the link is blocked, go to the article and click on the picture link.)

This is the same IPCC that the anti-nuclearists have been flogging as the last word on nuclear energy and carbon markets.

We are going to have to change our perspective on just what is and is not "green". There is no such thing as human technology without environmental consequence. Our practice of making planning decisions based on popular perceptions of "green-ness" is getting dangerous. Although scientific methodology isn't perfect, either, it is preferable to what we have been calling "common sense" or "the smell test". These "turnabout-is-fair-play" issues (e.g., the safety of nuclear energy generation, problems with wind farms, CO2 emissions from "natural" biofuels, mercury in CFL bulbs) aren't the result of irony, but mistakes in our reasoning.

--p!

[Dead_Parrot]

10. You misunderstand...

That a new hydro project generates GHG's is well known. What I have a problem with is the suggestion that this happens year after, forever: As your NS article mentions, there's an initial pulse, then a slowly declining dribble. Go to somewhere like the Grand Coulee Dam, and there's approximately fuck all decomposing matter lying around on the bottom after ~70 years: It's not going to be any different to a natural lake down there. Counting on my fingers, I reckon the maximum amount of methane from the GCD is about one million tons (21,000 acres at 40 tons of carbon per acre, converted entirely into methane): For 1 EJ every 12 years or so, that wasn't a bad price to pay.

[eppur_se_muova]

9. Brazil is doing a pilot project to capture reservoir methane (link)...

(BTW ... Brazil's National Institute for Space Research? How did THEY get this job? Maybe no one else was doing it, so they jumped into the breach. If so, kudos to them!)

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=95870&mesg_id=95870