Dam emissions, not so bad after all

From the Cary Institute of Ecosystem Studies

Greenhouse gas impact of hydroelectric reservoirs downgraded

Located on the middle of the Rio Grande, the UHE FURNAS reservoir is one of the largest in Brazil. It impounds the Grande River and has a capacity of 22,590,000,000...

Site design and location can minimize carbon dioxide, methane emissions

An international team of scientists has amassed the largest data set to date on greenhouse gas emissions from hydroelectric reservoirs. Their analysis, published today in the online version of Nature Geoscience, posits that these human-made systems emit about 1/6 of the carbon dioxide and methane previously attributed to them.

Prior studies based on more limited data cautioned that hydroelectric reservoirs could be a significant and large source of both carbon dioxide and methane to the atmosphere.

Through an analysis of 85 globally-distributed hydroelectric reservoirs, the authors revealed that these systems emit 48 million metric tons of carbon annually, a downgrade from earlier estimates of 321 million metric tons. Further putting things in perspective, hydroelectric reservoirs are responsible for less than 16% of the total carbon dioxide and methane emissions from all types of human-made reservoirs combined.

“Our analysis indicates that hydroelectric reservoirs are not major contributors to the greenhouse gas problem,” comments Dr. Jonathan Cole, a limnologist at the Cary Institute of Ecosystem Studies and one of the paper’s authors. “But there are some caveats. To date, only 17% of potential hydroelectric reservoir sites have been exploited, and impacts vary based on reservoir age, size, and location.”

IMAGE: Located in the State of Mato Grosso, the APM Manso Dam impounds the Manso River and has a capacity of 5,600,000,000 m3 and a surface area of 357 km2….

Click here for more information.

Carbon dioxide and methane are two of the main greenhouse gases created by human activities. Carbon dioxide is produced during the combustion of nearly any organic material; methane has a variety of industrial sources. Both gases are also produced naturally, particularly in wetlands and lakes.

When rivers are dammed to make the reservoirs needed for hydroelectricity, flooding creates lake-like conditions that generate carbon dioxide and methane. Emissions are the highest following reservoir construction, due to decomposing vegetation and soil organic matter. As reservoirs age, emissions decline, with cold-water systems stabilizing more rapidly than their warm-water counterparts.

Lead author MSc. Nathan Barros, of the Federal University of Juiz de Fora further explains, “The bottom line is that per unit of energy, hydroelectric generation produces much less carbon dioxide and methane emissions than previously thought, but impacts are not equal across all landscapes.”

The amount of greenhouse gases generated by hydroelectric reservoirs depends on where they are built, with the team’s analysis indicating that emissions are correlated with latitude and the amount of biomass in the watershed. With Barros adding, “Reservoirs in tropical locations, such as the Amazon, emit more methane and carbon throughout their lifecycles.”

Hydroelectricity supplies an estimated 20% of the world’s electricity and accounts for more than 85% of electricity from renewable sources. Future development is expected globally.

The paper’s authors urge careful consideration of site location and design. “During the environmental impact phase, it should be a goal to minimize the amount of carbon dioxide and methane emitted per unit of energy generated,” Cole notes.

To truly tease apart the emissions generated by hydroelectricity, the authors also call for a study that assesses a site’s carbon budget before and after reservoir construction. Pre- and post flooding analysis would clarify the net carbon impact of hydroelectric reservoirs.

###

Other contributors to the paper included Drs. Lars J. Tranvik, Yves T. Prairie, David Bastviken, Vera L. M. Huszar, Paul del Giorgio, and Fábio Roland.

The work was supported by grants from FURNAS Centrais Elétricas and from the Swedish Foundation for International Cooperation in Research and Higher Education (STINT).

The Cary Institute of Ecosystem Studies is a private, not-for-profit environmental research and education organization in Millbrook, N.Y. For more than twenty-five years, Cary Institute scientists have been investigating the complex interactions that govern the natural world. Their objective findings lead to more effective policy decisions and increased environmental literacy. Focal areas include air and water pollution, climate change, invasive species, and the ecological dimensions of infectious disease. Learn more at www.caryinstitute.org

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88 thoughts on “Dam emissions, not so bad after all

  1. Waiting for the anti-hydro power crew to show up here based on the anti-wind and anti-solar responses to those updates….

  2. In a warming world (if it actually is), there’ll be more rain therefore Hydro will be a more viable solution in more locations than otherwise

  3. “Emissions are the highest following reservoir construction, due to decomposing vegetation and soil organic matter. As reservoirs age, emissions decline,….”
    ==================================================================

    Oh, my……are they really that ……. … Yeh!! Cause the vegetation and organic matter wouldn’t decompose if the dam wasn’t built!!

  4. It also matters if the flooded land for the reservoir was logged or not before it was filled. Rotting wood at the bottom of a lake can generate a lot of methane. However, most states now require saleable timber to be logged before filling, but I know of some that were filled before this became a requirement. And BTW, although this means less GHGs are generated, it doesn’t really make a bit of difference to the climate.

  5. Observations don’t match projected estimates. (again)

    I wonder if the proverb, “a lie will go round the world while truth is pulling its boots on” applies wholesale to climate change science?

  6. Er, what purpose does evaluating the co2 and ch4 emissions over the life of a hydroelectric project serve? Electricity output; impact on homes, wildlife and habitat of damming; connection to grid; cost per unit; they’re the main factors to consider.

    Can they move on from obsessing over the carbon arseprint of cattle, etc, and get their senses back?

  7. suyts – yes and no.
    ========================================================
    Oh, my……are they really that ……. … Yeh!! Cause the vegetation and organic matter wouldn’t decompose if the dam wasn’t built!!
    ========================================================
    Decomposes differently at different rates and with different byproducts. For example, a log in a forest can take 50 years to decompose and much of the decomposition is immediately tied into the growth of other organisms such as moss, fungus, etc while the reservoir lake will decompose most of the plant matter in it within 10-15 years. Also, the type of decomposition that happens in open air is different than the decomposition in water – the air-decomposed log generates a LOT less methane than the log which is submerged.

    Don’t take me the wrong way – worrying about the CO2 and CH4 contribution of reservoir lakes is silly, but the scientists in this study aren’t the idiotic morons your comment suggests. There is a very distinct difference between the emissions of decomposing matter in a suddenly-created lake and the emissions of decomposing plant matter in an open forest/jungle/grassland.

  8. Just a question here; those early emissions from decaying plant matter; wasn’t that going to happen anyway? We call it autumn here in Iowa.

    As to the rest; seems like they’re grasping at straws. Can anybody explain the logic why hydroelectric dams produce substantially more CO2 than non-hydro?

    Can anybody explain why a reservoir would produce substantially more CO2 than a non-dammed river?

    I am sure there is some level of justification; CO2 required to perform maintenance on a hydro-electric, for example. But I don’t see where the volume would be sufficient to really be an issue and, outside of that example, I don’t see where a non-hydro dam would result in more CO2 at all, when compared to an un-impounded river eco-system.

    Just a couple of honest questions.

  9. The only solution to CO2 (or was that C) emissions is to remove the source – mankind!
    /sarc (as if really necessary)

  10. Having trouble believing that people actually get paid money to write this c***. How much CO2 does a dam emit?? FFS. This must surely be the high water mark for hysteria about a harmless, natural, plant-fertilizing trace gas essential for all life on earth.

  11. Methane is naturally produced by the anaerobic rotting of plants and animal remains in marsh, bog, wetlands in general. I would like to bet that research into these areas would show that these natural producers exceeds that of humans. Some real research is open to an enterprising PhD student.

  12. Bystander says:
    August 2, 2011 at 6:28 am
    Not in the same way or amounts suyts…

    Explain, please.

  13. News Flash: There is no “greenhouse effect” so, why are we wasting time talking about what contributes to it. It is a waste of time and effort and – wait a minute, why am I wasting time and…

    REPLY: There is in fact a greenhouse effect, otherwise the average temperature of Earth would be about 14F – Anthony

  14. Methane only contributes to greenhouse gases when it is burnt (eg a power station, car, industrial furnance or domestic appliance -eg kitchen stove). It does not burn when released into the atmosphere – on its own the IR absorption is insignificant. See the following post http://jennifermarohasy.com/blog/2011/07/natural-gas-more-polluting-than-coal-only-according-to-the-ipcc-a-note-from-cementafriend/
    A human contributes more effective greenhouse gas when breathing out CO2 than a ruminant bleching methane. The methane which might be released from a dam contributes nothing significant to the supposed greenhouse effect.

  15. If methane is a bigger problem than CO2, then it makes sense to burn the logging debris before filling the lake.

    I would also like to see methane levels compared between forests that are logged regularly and “natural” forests that rot in the old-growth stage.

  16. I have to bet the farm here that the largest volume of emitted GHG you’re going to get from a reservoir is water vapor. It wasn’t mentioned in the article, but water vapor really is in the top tier of climate affecting gases. I get the feeling sometimes that people just like to talk about CO2 rather than science.

  17. Good grief. To even mention that CO2 or methane is a problem regarding a hydro-electric dam….. I am speechless. Must be a different planet.

    Just visited the Hoover-Dam. A Great achievement for mankind. Something to be celebrated.

  18. Well I never! Being an ignoramus, I thought things didn’t get greener than hydroelectric. This throws a new light on the windmills. What about the emissions from the rotting carcasses of all the birds that get chopped and strewn across the countryside? How about the carbon dioxide being puffed and panted out by all those blasted humans when they climb up the endless steps inside the windmills in order to perform routine maintenance work? And emissions of vehicles they drive to get to those distant and hilly beauty spots defiled by windmills? And the factories that produce the confounded things? Oh dear! This world!

    Geoff A

  19. Cwaeth Dan Santo:

    Decomposes differently at different rates and with different byproducts.

    Indeed. The rapid, highly exothermic decomposition that releases massive amount of CO2 and soot on a timescale of hours or days rarely happens under water. I think we’re onto some serious science here.

  20. They seem to ignore the CO2 emissions avoided by preventing floods and reducing the need to pump groundwater for irrigation. Most hydroelectric dams in the US were built primarily for irrigation and flood control. Their electric generation functions are tertiary.

    Considering that specialized equipment exists to harvest lumber from dam reservoirs, it should be obvious that CO2 emissions estimates based on full decomposition of everything inundated were silly.

  21. dp says: August 2, 2011 at 7:41 am

    I have to bet the farm here that the largest volume of emitted GHG you’re going to get from a reservoir is water vapor. It wasn’t mentioned in the article, but water vapor really is in the top tier of climate affecting gases. I get the feeling sometimes that people just like to talk about CO2 rather than science.
    Can you imagine them trying to cap and tax H2O? what a riot!? (probably a double entendre)

  22. One of the things that’s always interested me is the amount of dissolved CO2 that will be released just by simple agitation as the water flows through the gates and turbines. Try as I might, I’ve never been able to find any figures for this. I don’t suppose anyone else has had any similar idle wonderings that might have borne a bit more fruit than my own?

  23. “When rivers are dammed… flooding creates lake-like conditions”.
    I always thought it actually created a lake ?

  24. @ Bystander and Dan Santo
    ============================
    Yes, the different way things decompose is acknowledged. And I don’t wish to generate any angst, however, a few things should be pointed out. Regardless of whether we add water or not, we still don’t create matter nor energy. Secondly, while the mechanisms are different, decomposition underwater also contributes to growth of life underwater. While there may be some quicker decomposition, there isn’t more decomposition. And while some materials will be discarded underwater, others that would, will not be.

    As it is, there are few things I can think of that could better waste more time and money as to attempting to quantify GHGs from building a hydro-electric dam. What the hell? After the dam is built and put in to use for generating electricity, what do we believe the net effect is vs. traditional electricity generation? We should do a study on how much GHG’s are released to the atmosphere by creating national parks and the maintenance required for such ventures.

    Sorry if there is confusion about my moniker….. I forget where I’m at sometimes.

    James ‘suyts’ Sexton

  25. Excellent, ask and ye shall receive… many thanks for the hockeyschtick link. That’s one of the things that I love about this place…. for those not interested enough to click the link above, the answer would appear to be a resonable amount ;-)

  26. James S;
    Exactly. Quicker, a one-time burst. Then that’s all she wrote.

    All aside, of course from the inherent inanity of fearing either CO2 or methane. The bleedin’ biosphere developed from those two resources.

  27. I’m not sure why there would be any additional methane or CO2 coming from dams since the vegetation in question would eventually die off and rot, anyway?

  28. So they’re trying to tell us an acre of lake (or pond) produces more CO2 and methane than an acre of forrest, swamp, farm, marsh, or grassland? My BS meter is pegged.

  29. Mike Bromley, indeed you did. 44% of their budget comes from Federal grants! The real problem does not seem to be CO2 but a higher education system which has run out of control. A Phd can be gained by putting ones name to a pointless piece of, as you say, claptrap like this. then you have your food ticket for life. A previous posting states that tides have not always been the same! The mind boggles. Another bunch have discovered that it is dryer in Texas than it was 12 years ago! I deeply resent paying taxes to keep these morons off the street when they would actually achieve more with a broom and a wheely cart on the street than they do now with their X-box and Nintendo computer models.
    . The next victims of this recession should be the “scientists” who pump out pointless research on government money. Each and every “scientist” should be made to work for a minimum of 10 years in a commercial industry before being granted a PhD, and then only if they can demonstrate a level of achievement or innovation above and beyond the norm.

  30. vboring says:
    August 2, 2011 at 8:00 am

    “They seem to ignore the CO2 emissions avoided by preventing floods…”

    Exactly ! Can you imagine what happened whenever the Colorado river flooded before the Hoover Dam? Lake-like conditions again, and again, and again…..Whole areas was flooded, ruining peoples lives. But who care about people…..

  31. Kaboom says (August 2, 2011 at 9:41 am): “I’m not sure why there would be any additional methane or CO2 coming from dams since the vegetation in question would eventually die off and rot, anyway?”

    Presumably a hypothetical forest on the reservoir site would be in carbon equilibrium, i.e. trees dying, decaying, and emitting CO2 and CH4 would be replaced by new trees sequestering new carabon. Covering the forest with water would lead to a one-time unbalanced release of carbon.

    I assume, though, that reservoirs have some biological activity, e.g. algae, peripheral marshland, fish, underwater plants, etc. which eventually reaches an equilibrium of its own. Not sure how that compares with the land ecosystem it replaces. As the article points out, your mileage may vary depending on what the reservoir replaces.

    And if the hydro installation replaces a coal-burning power plant…

  32. To put this into some sort of perspective, shouldn’t they have stated what the area of hydro-electric dammed lakes is compared with naturaly occuring lakes?

  33. This news comes as a real relief. I have been very worried about this. Finally, I can get some sleep.

  34. Any news on the Three Gorges Dam in China? Not from the the CO2 it might release, just the effect of the increasing mass of water on the ground underneath.

  35. If there’s loads of methane being outgassed as the water passes through the turbines, couldn’t it be collected and used to drive a gas turbine? If this is not viable, maybe the methane could be burnt off if methane is so much worse than CO2?

  36. “the authors revealed that these systems emit 48 million metric tons of carbon annually (my bold)

    Blimey – what is happening to all that carbon? Are we harvesting it? Is it being burned in coal power stations?

    /sarc

  37. @ Dan Santo,
    Aug 2, 2011 @ 6.38 am

    I’m calling you out on this on, or at least any source of information that you have imparted to this thread. Please provide citations as to your claim that it takes 10-15 years for a log to decompose in H2O as to 50 years in air (with all the claimed benefits in air). If you can provide documentation as to your claims that would withstand the scrutiny of a serious review, I will apologize. DO NOT consider this an apology at this point

    There is a log that I used to cross a medium size stream that was washed out on the ends by high water about 35-40 years ago and ended up creating a low dam if you will. It has long ago filled in on the upstream side but the log is still visible. Still solid as the day submerged. I know as I nailed a plank to it a couple of years ago in low water so I could cross to hunt. The other timber (trees) that were felled and ended up on the shore have long since decomposed. Also a manmade lake in my area was flooded in the very earlier 60’s with standing timber in the depths that would be completely covered when the lake was filled. These are the GO TO regions to catch fish. Fish locator shows submerged timber just as it was on maps created over 50 years ago.

    I had the opportunity to float the Upper James River in Virginia, where in the very early history of this country, long before the invent of the railroad, the river was used for transportation of goods/raw materials (pig iron, coke, etc) to Richmond, Va to be used in the progress of this country. There is a series of locks (primitive by today’s standards) utilizing wooden timbers submerged in the river bottom to divert some of the river flow into the adjoining canal to get around the shallow water rapids. The timbers are still there today and not at all decomposed! I believe that President George Washington signed an appropriation bill to complete this project.

    There is a place in the National Forest in Virginia that has a dam built with 4 or 5 large white pine logs to provide a pool for the transfer of water to a gravity fed pipe to an off stream pond/lake. I would guess it has been there for over 40 years Still there and looks good. The NF recently spent a couple of hundred thousand dollars above the purchase price of the property for renovations and did not replace the log dam. I would guess that if it were the least bit justified, they would have spent all they could get.

    Logs are still sought for harvest from some area in the Great Lakes that were submerged and lost (I believe over a 100 years ago). They are used for exotic and specialty wood products. At one time the Japanese purchased from the USA and submerged timber for preservation (probably does not apply as to the discussion of this thread due to salt water).

    Perhaps another look into the past ‘science’ is in order. Possible reservations for a spot on the chopping block of past junk science may be in order. The greens have/are burning their bridges and the above referenced post/comment just may be the match for another bonfire. Common sense and observations are going to be hard to trump.

    If you are new to this site, welcome to an eye opener to the truth. Beware of what you post as Anthony has an army of many ones!

  38. Bystander,
    Once again you make bad assumptions. Nobody here is reflexively against any form of energy. What we oppose is the subsidizing of energy forms that cannot compete on their own.

    This does not apply to hydro. Therefore the only people who are reflexively against it are your fellow eco warriors.

  39. Dams were reviled for years by greens, and they made study after study to make hydro-electric look bad and as such some areas of the world to this date have not maximized their potential for what is probably the BEST source of power that is CO2 free. These studies should come as no surprise, as the original studies were at best just shoddy science.

    They are also anti-nuclear, another source of power that is “CO2 free.” It just makes no sense when you look at what they advocate. This is the problem with combining science with politics. We can not learn anything of value until people learn that science has to be unbiased otherwise you get religious like pronouncements.

    And I can not begin to describe how much dams (When run correctly) can stop floods in their tracks. Any flooding that occurs could easilly be stopped by a good system of large dams. This is the issue on the larger rivers in the world which still flood because we do not control them. I still do not see how the argument that allowing the rivers to flood periodically is better then just having a permanent area flooded. Just ZERO common sense…and that is why green organizations should be kept away from science.

  40. oeman50 says:

    It also matters if the flooded land for the reservoir was logged or not before it was filled. Rotting wood at the bottom of a lake can generate a lot of methane. However, most states now require saleable timber to be logged before filling, but I know of some that were filled before this became a requirement.
    At least one company has developed a remote controlled mini-sub to log trees in such lakes. Since this is commercially viable it looks like wood dosn’t rot that quickly in fresh water lakes.

  41. Bystander says:
    August 2, 2011 at 6:03 am

    Waiting for the anti-hydro power crew to show up here based on the anti-wind and anti-solar responses to those updates….
    You misunderstand (as usual). What rational people object to is being forced to pay for more expensive, and less reliable energy sources (such as wind and solar), based on the idiotic notion that “carbon” is bad. As long as hydro can stand on its own, and doesn’t require subsidizing, then it is usually fine as an energy source.
    I say usually, because, here in New Hampshire there is an issue with Hydro Quebec and PSNH trying to railroad through a gigantic transmission line project, called “Northern Pass”, which has a number of issues, among them being destruction of wilderness in the northern part, and some land-taking through emminent domain, as well as destroying some of the beauty of the state. The power isn’t even for NH, but rather for Massachusetts and Connecticut.

  42. Well now, article not only states the impact is less then thought but also says hydro is green, renewable power. Now that it’s official I wonder if Oregon legislature can relabel our hydro power as green.

  43. Carbon dioxide and methane are two of the main greenhouse gases created by human activities.

    As dp has already noted, water vapor is an even bigger GHG produced by human activities, such as irrigation, tree planting, exhalation, showering, hydrocarbon combustion, and even dam building.

    If CO2 is a global enemy, then H2O is Global Enemy No. 1. Why is the EPA not cracking down on H2O emissions? The biggest source of this “pollutant” is evaporation from the oceans. Fortunately, Exxon and BP now have the combined technology to reduce oceanic air pollution, by ramming tankers into oil rigs so as to cover the water with a film of oil. If you want to save the world, you have to be willing to make a few sacrifices! \sarc

  44. What am I missing here? It was my belief that trees, and thus wood, submerged in water does not break down. Kariba Dam on the Zambezi was flooded around 1957 creating Lake Kariba. There were hundreds upon hundreds of acres of trees submerged and semi-submerged. They are dead of course, but the trees themselves are still there some fifty or so years later. Couldn’t have been a lot of CO2 generated from that source. Great for the bream and tiger fish that inhabit the lake and great for those of us who have been privileged to fish there.

  45. Since the total estimated carbon from dams (48 million tonnes annually) is only six-tenths of one percent (0.6%) of the total emissions of carbon from fossil fuels (about 7 billion with a “b” tonnes annually), even if it were an issue it wouldn’t be an issue.

    w.

  46. eyesonu says:
    August 2, 2011 at 11:15 am

    In my home town there is a hydro power plant that uses wood from an African tree for the bearings on the shafts. The wood gets harder submerged over time. The plant was originally built by Union Carbide to make acetylene, but when UC left became a commerical enterprise. Wood better than steel for bearings who’d a thunk it.

  47. So now the latitude-based carbon emissions-reduction rankings are:

    Tropics and near-tropics: Solar, perhaps wind.
    Mid-latitudes: Nuclear, solar and wind where practical, hydroelectric.
    Polar and near-polar: Nuclear, possibly wind (equipment issues), possibly hydroelectric.

    Wait, do the residents of the tropics and near-tropics want reliable continuous electricity as well? If “warm water” reservoirs are “the worst” for carbon emissions, then there can’t be open-air reservoirs for hydroelectric-based pumped storage. There is no other practical form of pumped storage, other storage methods still aren’t practical.

    So the tropics and near-tropics get nuclear as well. Also, since nuclear is base load, for the peaks as needed there are fast-reacting gas turbine plants using methane generated from “inevitable” sources like landfills and sewage, suitable for all latitudes (provided they’re protected from too-cold temperatures).

    Problem solved (assuming there is a problem).

  48. Bob Kutz asked some good questions above. I don’t see that anyone’s answered yet so I’ll take a crack at it. In reverse order:

    > Can anybody explain why a reservoir would produce substantially more CO2 than a non-dammed river?

    Damming the river floods much of the surrounding hillside, killing all the grasses, trees and bushes that lived there as the reservoir fills. While those plants are replaced by water-plants (algae, etc), the total biomass is much smaller, at least according to these researchers. The net loss of biomass becomes a net gain of gas when the it rots. Assuming steady-state, this is a one-time hit, I think.

    > Can anybody explain the logic why hydroelectric dams produce substantially more CO2 than non-hydro?

    Hydroelectric dams are designed to keep more of the water moving than non-hydro dams. While both will kill the plants on the surrounding hillsides as the reservoir fills up, the non-hydro dams have a good chance of becoming anerobic at the bottom fairly quickly. If it happens fast enough, the dead trees, etc may never rot at all. Hydroelectric dams will tend to keep the bottom water moving more, keeping the water aerobic and allowing decomposition to progress.

    The movement of water also affects the temperature distribution, keeping the bottom water from getting as cold as in a more still reservoir. (See above about the reason temperature affects decomposition.)

    Hope that helps.

  49. CO2 is NOT the complete story about dams. Believe me I’ve been underground at the Upper Churchill hydro Project in Labrador and I’ve seen the effect of said dam downstream. What used to be CHURCHILL FALLS with a much larger and higher falls than Niagara Falls (only talking about the Canadian Niagara Falls) is NOW reduced to a mere trickle you can almost catch in a bucket. Which changed the entire course of the Churchill River all the way down to Happy Valley-Goose Bay. Salmon used to run in that river but no longer – resulting in a much lower river now full of sand bars in essence changing the landscape. I drove back there four years ago to see the once might falls reduced to this is heart breaking scene. It makes me sick every time I see that image in my mind all over again.

    The worst part – we only wanted jobs at the time and could never imagine the after effects – we only saw jobs. I was one of them that just wanted a job. I never knew what the true cost of damning a river such as the Churchill meant and I probable didn’t want to know either. I don’t think any of us understood. The sad part after construction none of us had jobs anymore and Quebec got all the benefits signed away for 100 years. Today they’re going to build another dam on the Churchill River about thirty miles from Happy Valley Goose Bay. The same thinking I had back then is being said all over again. I understand people need the jobs modern society brings but I’m not so sure folks understand the consequence of another dam on that once vibrant river system.

  50. What almost everyone forgets regarding alternative energies, including hydro, is how much carbon dioxide was poduced and btus were burned to manufacture and erect these monuments to energy stupidity.

    Hydro in particular uses an enormous amount of concrete. Concrete is about 1/3 cement. Cement making accounts for about 4% of all the CO2 put into the atmosphere by man. (Man only accounts for 3.27% of all CO2 put into atmosphere.)

    Does anyone know what the Energy Returned On Energy Invested (EROIE) is for hydro?

  51. Chilli @ 6.56 am sums it up well. I cannot believe they have sunk the level of lunacy so far in their efforts to find topics to research on this thoery.

  52. From mkelly on August 2, 2011 at 1:10 pm:

    In my home town there is a hydro power plant that uses wood from an African tree for the bearings on the shafts. The wood gets harder submerged over time. (…) Wood better than steel for bearings who’d a thunk it.

    http://www.plantservices.com/articles/2005/469.html

    Wood bearings in the new millennium
    They have been supporting rotating shafts quite successfully for thousands of years and will continue to do so in the future.
    By J.R. Steurnagle, Woodex Bearing Co., Inc.,

    When the steering sweeps on ships gave way to vertical rudder shafts, wood was the bearing material of choice. Lignum vitae, an extremely dense, tropical hardwood, was soon found to be best for this and other submerged marine applications. So dense that it will not float, “lig” has a high natural oil content, making it self-lubricating and especially resistant to deterioration in water.

    When kept wet, as in most shipboard applications, lig possesses tremendous strength and wear resistance. When steam propulsion arose, lignum vitae became the bearing for propeller shafts, and it was common to see bearings last scores of years–frequently as long as the ships themselves.

    Lignum vitae naturally attracted landlubbers’ interest, and it became a popular bearing material for waterwheels. Many hydro turbines today still operate on lignum vitae bearings installed fifty or more years ago, despite having received little or no maintenance since their installation.

    There’s a pdf on the construction and use of wood bearings. The originating source:

    http://practicalaction.org/docs/technical_information_service/oil_soaked_wood_bearings.pdf

    Problem is it’s not downloading well for me, and what came through was reported as damaged, unreadable. I found it at this alternate site, use download link:

    http://sheltercentre.org/library/oil-soaked-wood-bearings-how-make-them-and-how-they-perform

    M$ Word in pdf, opened just fine.

    Important warning! As found out by knifemakers using “exotic woods” for handle materials, these naturally-oily woods can be very dangerous. Search for “exotic wood dust danger” for more official info, here’s a blog thread with precautionary advice and anecdotal reports. Severe allergic reactions can be triggered by dust or even mere skin contact with the wood. IIRC people have died from exposure, come to think of it since a person can die from a single peanut I would be surprised if no one had died.

    Oh, and as a “The state of California has determined” warning, the dust is carcinogenic. Apparently technically all wood dust is carcinogenic as well.

  53. The very best way to season timber before use is to submerge it in water for a decade or three, they do not rot they season naturally without warping or splitting. Look up records of ship building from centuries past. This rotting log stuff in lakes is BS.

  54. Charles S. Opalek, PE says:
    August 2, 2011 at 2:34 pm

    Does anyone know what the Energy Returned On Energy Invested (EROIE) is for hydro?
    ======================================================

    Charles I don’t have it with me at the moment, but I can probably get it at work. But my thoughts are that as time passes, it surpasses any other source of electricity. The pricing certainly beats anything else. Coal and Nuke included. While it does take a great bit of energy to place a generating dam, once in place, its relatively done as far as energy invested. Sure, there’s maintenance and monitoring, but the fuel is free and is delivered to the generator with no further investment. The life expectancy of a turbine in out of this world! There’s some over 50 y/o still in use! (If we updated them, we’d prob get more generation…….)

  55. An international team of scientists has amassed the largest amount of gravy from the Carbon Scaremongering Gravy Train. They have determined yet another useless speculative number concerning a minuscule amount of a harmless gas and managed to leech off of the tax payer for another couple years. A spokesman from the The Journal of Speculative BS propaganda, aka Nature, stated that we need more taxes and less public access to data and journal articles through the implementation of a complex pay-wall system based on a points wise analysis of the readers belief in AGW.

    Sport Now. Go to sleep.

  56. To all the “logs don’t rot in lakes” commentors,
    1) Some logs, some lakes – it depends on the type of wood and the temperature, aeration, acidity and other factors of the water.
    2) Logs don’t actually matter anyway. The majority of the biomass of a tree is in its leaves, not in the trunk. (This, of course, depends on the type of tree.) And thats even before factoring in the biomass of the grass, shrub and other sunken vegetation. No matter how many unrotted logs you’ve found, it’s exceptionally rare to find a deposit of unrotted leaves or grass unless the water is very cold, still and anaerobic.

  57. Mike(One of the Many) says:
    August 2, 2011 at 8:09 am
    One of the things that’s always interested me is the amount of dissolved CO2 that will be released just by simple agitation as the water flows through the gates and turbines. Try as I might, I’ve never been able to find any figures for this. I don’t suppose anyone else has had any similar idle wonderings that might have borne a bit more fruit than my own?

    Precious little. You may be imagining the water to be “seltzer-like”, where the liquid phase is supersaturated with CO2. When you drop the pressure, out comes the fizz. Lake or impoundment water has a very low bulk flow rate and is in equilibrium with the CO2 content of the air. Only temperature changes will affect the net flux of CO2 in the water that flows through the turbines.

  58. Wil says:
    August 2, 2011 at 2:23 pm

    Dams do not decrease the flow rate of a river once the water is held in reserve. You see, once the water is there, its a question of the people manning the dam to speak who are not doing their jobs. You can not blame a dam for low flow after the river is back to its flow-rate.

    In the case of the river always “flowing at a certain rate..” Well its probably just as likely that it happens like that too at times that it is in drought and the flow-rate is reduced. Dams do not stop water from flowing, people do. When people take water out of the system as in Colorado this is something to be concerned about. When people do not take flow rate and environmental concerns such as fish into consideration, this is a concern. You can solve these problems easilly and flow-rate is never reduced by dams. Its all depended on water flowing into the system.

    So as you can see…. its more about the management of the dam after the fact then anything else. But by saying dams ruin the country-side is really not looking at the big picture. They add to the country-side by creating a lake that is permanent instead of flood-plains that flood periodically and can not really be used for anything of value.

  59. Further putting things in perspective, most of Earth’s methane is emitted by the oceans, and most of it is probably of abiotic origin. I was taught to regurgitate the phrase “fossil fuel” without consideration, as if the explanation not only had some scientific merit, but was established fact. I was also taught that methane is a biological molecule and a sign of life. Recent discoveries undermine and contradict these myths.

    1) “The [Martian] methane could be a byproduct of volcanic gassing. Or it could be the chemical reaction between water and rocks in the soil and crust.”

    http://news.nationalgeographic.com/news/2004/10/1007_041007_mars_methane.html

    2) “…a hydro-geological process between water and rocks deep inside the moon could be producing [Titan's] methane.”

    http://esse.engin.umich.edu/PSL/PRESS/Titan_Cassini_Huygens/AP_Wire_012705.pdf

    3) It is also argued that atmospheric methane can come from volcanoes or other fissures in the planet’s crust and that without an Isotopic signature it is difficult to say what exactly was the origin.

    http://en.wikipedia.org/wiki/Methanogenesis

    4) But that does not solve the larger question of why methane in the atmosphere seems to have reached a plateau. “The scientific community agrees that the pause is source-driven rather than sink-driven, that is, caused by decreasing emissions of methane,” Simpson says:

    http://www.scientificamerican.com/article.cfm?id=mysterious-stabilization

    No special pleadings for Earth!

  60. In the hydo reservoirs down the road there are entire forests of trees underwater from when they built the dams, one in 1905, one in 1930. When they lowered the water to fix the dams people were shocked that they were water skiing above a forest of trees only 3-5′ below the surface. Many had to be knocked down for safety reasons.

    As far as AGW, I would theorize that the dam would be a net positive. The waterfalls used to put up a tremendous water vapor. Now the river slowly boils out water at the base of the dam. Likewise while there isn’t a forest or grasslands under the water any more, there is a whole biosphere of plant life that probably represents far more flora than the earlier forests did. It also provides clean energy.

    The biggest CO2 producer for the dams probably be tourism as people boat, fish, swim, and catch a sunset. Next would be the licensing process that took 8 years and a 40,000 page document plus supporting studies.

    The hydo projects don’t leave the rivers dry as happens some places, they are ‘Run of River’, what goes in goes out and water levels in the reservoir are maintained within inches, unless they fall below minimum flow to support the river downstream.

  61. Bloke down the pub says:

    If there’s loads of methane being outgassed as the water passes through the turbines, couldn’t it be collected and used to drive a gas turbine

    Or add a little butanethiol and sell it.
    Methane also works as fuel for a four stroke spark ignition engine.

  62. Viv Evans says:

    “the authors revealed that these systems emit 48 million metric tons of carbon annually“ (my bold)

    Blimey – what is happening to all that carbon? Are we harvesting it? Is it being burned in coal power stations?

    It dosn’t help that these kind of people frequently say “carbon” when they actually mean “carbon dixoide” so they may actually mean 12Tg.

  63. Finally! We finally have something we can use! Thank you Lord! Oh, thank you!… wait a minute… uhoooh… that means the Warmistas will want to build Arks, well at least one, and seed the atmosphere, and they probably wont let two Coolists on board… WE’RE DOOMED!!!! We just can’t win. Oh well, what’s on TV Martha?

  64. Re: Mike Rossander, August 2, 2011 at 2:20 pm,

    Thanks for that info.

    I now see why the hydro would probably produce a more efficient transfer of the existing biomass into CO2, and why there would be a net decrease in sequested CO2 from any reservoir.

    Not sure why this is a big issue, but I suppose until it was studied, no one really knew how big of an issue it could be.

    Anyway, thanks again.

  65. On second inspection, however, the paper seems to indicate that they are concerned with ongoing emissions from hydro-electric. I can see the one time effect of converting a certain terrestrial biomass to an aquatic state and lowering the overall amount of CO2 sequestered (in trees for example), but the amount of CO2 and methane actually generated by the hydro-plant’s ongoing operation should be near nil, except for the before mentioned maintenance requirements.

    Still not sure why this has any validity whatsoever.

    Let’s say you could instantly convert a free flowing river to a hydo-capable impoundment with a mature biomass; the difference in CO2 content from state 1 to state 2 would be the only difference, as the hydro dam doesn’t actually produce CO2 or methane in it’s operation.

    “Through an analysis of 85 globally-distributed hydroelectric reservoirs, the authors revealed that these systems emit 48 million metric tons of carbon annually, a downgrade from earlier estimates of 321 million metric tons. Further putting things in perspective, hydroelectric reservoirs are responsible for less than 16% of the total carbon dioxide and methane emissions from all types of human-made reservoirs combined.”

    Now I don’t get where either the 48 or 321 metric tons comes from, once the existing vegetation becomes flooded and releases its CO2. That should be the end of it; beginning state minus end state equals total amount of emmission, not an annual figure, but a total figure divided over a period of one or two years and then done.

    Their paper still doesn’t make much sense. Once the landscape is changed the CO2 state should remain at equilibrium, producing no additional CO2, hydro or not.

  66. At last I can compare a Hydro electric lake to an SUV. Now all we need to do is convert to a rate for electic cars and we’ll have a universal measuring system to compare buses to swimming pools.

  67. Obviously, we’re damned if we do and damned if we don’t, so the only thing that’s going to make the environmentalists happy is for us plebes to kindly report to the suicide booths. Our remains can go to make soylent green.

  68. re: Bob Kutz’ “On second inspection…”

    I concur and was assuming that the researchers were ‘amortizing’ the one-time hit over some unspecified period to show a per-annum rate. I can’t find anything in the paper to confirm it, though. I do find several comments about hydro dams encouraging more mixing and therefore being less effective as carbon sinks than the more static water bodies behind a non-hydro dam but that doesn’t challenge your first assumption that at equilibrium it should approximate the original free-moving river.

    Their main point, however, is merely that the analysis done on temperate-climate dams will be significantly different from the analysis on a dams in a tropical climate. Given the difference in total flooded biomass (much greater in tropical areas) and the difference in ratio of leaf biomass (which rots readily) to trunk biomass (which doesn’t), this is unsurprising. But now it’s a bit better quantified.

  69. The sahara loses more heat at night than it gains during the day – the only reason it stays warm is wind. Why do deserts lose so much heat at night – simple, lack of water – the GHG that accounts for 99% of all warming

  70. “…flooding creates lake-like conditions that generate carbon dioxide and methane.”

    So, why didn’t the EPA outlaw the recent flooding of the Mississippi River?

  71. Perhaps reading the following post, “Carbon sequestration through hydroelectric generation: A variable never considered.” show first ever written about the problem. But there’s only one problem, it is written in Portuguese (but now with the Google translation !)

  72. Google “Lake Nasser,” and “Aswan Dam,” and “Toshka Lakes,” and “New Valley Project.”

    What fun it would be to get paid for trying to figure out how all this diversion of the Nile River is adding and subtracting to levels of H2O, Methane and CO2 in the atmosphere, and is adding and subtracting to the world’s stored carbon supply.

    Great work, if you can get it.

  73. It’s simple. If studies show that hydroelectric power is responsible for producing greenhouse gasses, it can be taxed in the future.
    The only anomaly of this theory is that there isn’t taxation yet on greenhouse gasses, but can be explained that the last attempt to introduce a global tax system luckily failed. The idea of a global co2 tax is still an orgasmatic solution of a non-existent problem by leftish thinkers.

  74. I believe the following paper is of relevance:

    http://www.un.org/esa/sustdev/sdissues/energy/op/hydro_tremblaypaper.pdf

    Highlights:

    Temperate and boreal hydroelectric reservoirs produce far below the average of traditional thermal alternatives (8% max, Full Energy Chain, in gCO2 equiv./ kWh(e).h).

    Dams in tropical regions vary significantly, from 1% to 200% of traditional thermal alternatives.

    Much of the average emissions come from the initial decay of organic matter; It is expect that emissions will decline over time.

    Hydro-electric generation is on average comparable in total average emissions with other renewables in tropical regions; There exists however a considerable variance. In temperate and boreal regions however, hydro-electric generation is by far the lowest in total average emissions /kwh )

    Interesting that Nuclear also fares favorably compared to renewables (probably due to manufacturing processes).

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