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A friends works as an ecologist and are a scientist at a university. Water Dams disrupt/destroy eco systems downstream. Hydro power is thus not fully green due

by acd 6y ago

A friends works as an ecologist and are a scientist at a university. Water Dams disrupt/destroy eco systems downstream. Hydro power is thus not fully green due to that. Water power has to be compared to The alternatives such as oil/coal. One should not view water power as fully “green” energy. Fish species are for example disrupted by water dams.

generatorguy 6y ago
I’ve worked on about 30 different run of river hydro electric projects over the last 15 years. Yes there is some environmental impact but the ones I have worked on have had a team of biologists and years of environmental studies and they would never result in a dead fish any more often that the river would have naturally by itself. If any habitat is destroyed they have to create new habitat such as spawning channels. They probably spend 10%-20% of the entire budget on environmental. These run of river plants don’t flood more than 1000m^2 area, use a weir instead of a dam, leave water in all sections of the river channel, and don’t cause unnatural changes in the river level at a rate greater than 1” per hour which is a very conservative rate compared to what the rivers of this size and nature naturally do by themselves when it rains or melts. I know you said Dams and not weirs and not run of river plants, and big dams have their issues, but not on the same scale as the oil industry.
- bjelkeman-again 6y ago
  I have studies hydropower effects at my university programme, and a vocational aquaculture program, and as you say, there are definitely ways to lower the impact. In Sweden, all the major rivers except for two have large scale dams installed. Most of that was built between 1900 and 1950 and not much after 1970. Not much consideration for biodiversity or environmental impact was taken into account. At some point hydropower supplied 95% of Swedish electricity. Important during the country’s industrialisation. There is a nice reference list, including many English language reports at the end of this report from the Swedish Agency of Marine and Water Management. [1] I think they summarise it nicely by saying “Hydropower is one of the biggest impacts on the ecological status of a river. At the same time it is one of our most important energy sources.” [in Sweden] Sources: [1] https://www.havochvatten.se/hav/uppdrag--kontakt/publikationer/publikationer/2013-10-15-vattenkraftens-paverkan-pa-akvatiska-ekosystem.html https://www.havochvatten.se/hav/uppdrag--kontakt/publikation... https://sv.m.wikipedia.org/wiki/Vattenkraft_i_Sverige https://sv.m.wikipedia.org/wiki/Vattenkraft_i_Sverige
- helldritch 6y ago
  I'm curious how well this applies to the short-term effects of filling the Grand Ethiopian Renaissance Dam? [1] As I understand it a lot of the downstream ecological effects rely entirely on the fill rate the Ethiopians choose (3 years, 5 years, 10 years, 15 years, etc). A fast fill rate (5 years or less) could have significant short to medium term effects on the arable land downstream in Sudan and especially Egypt. The dam is oversized for its power output (to ensure it can meet peak output demands during the wet seasons) and will operate as a fish trap, cutting the number of fish able to head downstream (and ultimately to the sea / mouth of the Nile) by a significant amount. [1] https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Dam https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Da...
  - generatorguy 6y ago
    Large dams are a different ball game than the small run of river plants I have worked on and the ones discussed in the article. Even at large dams it is possible to build fish ladders to allow migration. When we were filling our head ponds (reservoir) we weren’t allowed to impound more than 10% of the total flow in the river.
James_Henry 6y ago
I understand the link posted here is specifically about dams on the Hudson. I question in general whether one can really say that all dams are such net negatives for ecosystems. Would we not be able to get hydroelectricity from a beaver style dam? and are those dams not generally seen as helpful to promote certain often very beneficial ecosystems? Also, in some sense, wind and solar power aren't fully "green" energy because they require giant turbines and solar cells that require a lot of polluting to make, maintain, and eventually dispose of. We still, of course, seem to consider them to be green and beneficial, I assume because someone has done the calculus to see that the costs of their pollution is less than the benefit of their use. I'm willing to bet that many dams are similar.
- Arnt 6y ago
  We can get electricity from any kind of dam except one that blocks all water forever. We get electricity when water flows through, see? The best kind of dam from the point of view of the power utility is one that allows the water flow to scale freely from zero to overwhelming to match electricity demand, and never allows water to bypass the turbines. But that's an extreme, not the only kind that makes financial sense. If you both reduce the time flexibility and also allow some water to bypass the turbines, you can usually get most of the power at a small environmental cost... usually, not always.
- tvaughan 6y ago
  This https://www.outsideonline.com/2413366/steelhead-fish-return-elwha-river-washington-dam-removal https://www.outsideonline.com/2413366/steelhead-fish-return-... was posted yesterday about dam removals in the Pacific Northwest, and the subsequent return of steelhead trout to the rivers.
adrianN 6y ago
There is no fully "green" power, but almost everything is better than climate change.
- Cthulhu_ 6y ago
  I think "green" is not the right moniker here; "renewable" covers it better I think. With (with my limited knowledge, naive opinion) solar panels and wind farms having less of an impact than hydro dams.
  - rocqua 6y ago
    Judging only on 'renewable' the ecological impact of a hydro-electric dam doesn't matter. The energy extracted here is renewable. Because rain will keep falling and thus the reservoir will keep being filled. The fact that it damages an ecosystem does not count there. Moreover, the fact that dams damage an ecosystem have very little bearing on the global-warming effects of dams. Whilst I do not want to say that ecological damage is not important, I think it is an issue that 'green' and 'ecological' have dual meanings. The current main usage being "Does not cause greenhouse gasses" with a less used original meaning of "Is good for the environment". This causes a lot of friction between people who use the same words but care differently about environmental impact beyond global warming. It used to be that caring about the environment was a fringe movement in so far as getting political change. Global warming has gotten 'being green' on the political agenda. But it sometimes feels like some of the more extremist green ideas have snuck into the greater public discourse under the guise of being 'green'.
Retric 6y ago
Many dams are going to exist due to flooding, irrigation, etc. Extracting hydropower once you have already decided to build a dam is as close to fully green as it gets. That said, there are many low head dams built exclusively to extract power, and many of those are no longer serving a useful purpose.
philshem 6y ago
The standard term is “renewable”, and yes, there are environmental concerns for any type of human-engineered energy production. For run-of-river hydro power, one mitigation is fish ladders: https://en.wikipedia.org/wiki/Fish_ladder https://en.wikipedia.org/wiki/Fish_ladder
BurningFrog 6y ago
I wish people would distinguishing destroying eco systems from changing them. A dam changes the eco system, but nature forms a new balance around the new geographical feature that is not inherently worse, just different.
epx 6y ago
Sometimes there are positive unintended effects. Near my city, there are a number of small hydro plants and dams, built before a grand national syncrhonized system was ready. While the dams were built inside very preserved forests, so there was initial damage, the surrounding area (tens or hundreds of sq. km) were put under protection to guarantee the water supply, so no reforestation, no agriculture, etc. Now even the surrounding areas are in better shape today than in the 1960s when the dams were built. Of course it helps the individual size of each plant is small (tens of MW, tops).

by acd 6y ago

generatorguy 6y ago

I’ve worked on about 30 different run of river hydro electric projects over the last 15 years. Yes there is some environmental impact but the ones I have worked on have had a team of biologists and years of environmental studies and they would never result in a dead fish any more often that the river would have naturally by itself. If any habitat is destroyed they have to create new habitat such as spawning channels. They probably spend 10%-20% of the entire budget on environmental. These run of river plants don’t flood more than 1000m^2 area, use a weir instead of a dam, leave water in all sections of the river channel, and don’t cause unnatural changes in the river level at a rate greater than 1” per hour which is a very conservative rate compared to what the rivers of this size and nature naturally do by themselves when it rains or melts. I know you said Dams and not weirs and not run of river plants, and big dams have their issues, but not on the same scale as the oil industry.

bjelkeman-again 6y ago
I have studies hydropower effects at my university programme, and a vocational aquaculture program, and as you say, there are definitely ways to lower the impact. In Sweden, all the major rivers except for two have large scale dams installed. Most of that was built between 1900 and 1950 and not much after 1970. Not much consideration for biodiversity or environmental impact was taken into account. At some point hydropower supplied 95% of Swedish electricity. Important during the country’s industrialisation. There is a nice reference list, including many English language reports at the end of this report from the Swedish Agency of Marine and Water Management. [1] I think they summarise it nicely by saying “Hydropower is one of the biggest impacts on the ecological status of a river. At the same time it is one of our most important energy sources.” [in Sweden] Sources: [1] https://www.havochvatten.se/hav/uppdrag--kontakt/publikationer/publikationer/2013-10-15-vattenkraftens-paverkan-pa-akvatiska-ekosystem.html https://www.havochvatten.se/hav/uppdrag--kontakt/publikation... https://sv.m.wikipedia.org/wiki/Vattenkraft_i_Sverige https://sv.m.wikipedia.org/wiki/Vattenkraft_i_Sverige
helldritch 6y ago
I'm curious how well this applies to the short-term effects of filling the Grand Ethiopian Renaissance Dam? [1] As I understand it a lot of the downstream ecological effects rely entirely on the fill rate the Ethiopians choose (3 years, 5 years, 10 years, 15 years, etc). A fast fill rate (5 years or less) could have significant short to medium term effects on the arable land downstream in Sudan and especially Egypt. The dam is oversized for its power output (to ensure it can meet peak output demands during the wet seasons) and will operate as a fish trap, cutting the number of fish able to head downstream (and ultimately to the sea / mouth of the Nile) by a significant amount. [1] https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Dam https://en.wikipedia.org/wiki/Grand_Ethiopian_Renaissance_Da...
- generatorguy 6y ago
  Large dams are a different ball game than the small run of river plants I have worked on and the ones discussed in the article. Even at large dams it is possible to build fish ladders to allow migration. When we were filling our head ponds (reservoir) we weren’t allowed to impound more than 10% of the total flow in the river.

James_Henry 6y ago

I understand the link posted here is specifically about dams on the Hudson. I question in general whether one can really say that all dams are such net negatives for ecosystems. Would we not be able to get hydroelectricity from a beaver style dam? and are those dams not generally seen as helpful to promote certain often very beneficial ecosystems? Also, in some sense, wind and solar power aren't fully "green" energy because they require giant turbines and solar cells that require a lot of polluting to make, maintain, and eventually dispose of. We still, of course, seem to consider them to be green and beneficial, I assume because someone has done the calculus to see that the costs of their pollution is less than the benefit of their use. I'm willing to bet that many dams are similar.

Arnt 6y ago
We can get electricity from any kind of dam except one that blocks all water forever. We get electricity when water flows through, see? The best kind of dam from the point of view of the power utility is one that allows the water flow to scale freely from zero to overwhelming to match electricity demand, and never allows water to bypass the turbines. But that's an extreme, not the only kind that makes financial sense. If you both reduce the time flexibility and also allow some water to bypass the turbines, you can usually get most of the power at a small environmental cost... usually, not always.
tvaughan 6y ago
This https://www.outsideonline.com/2413366/steelhead-fish-return-elwha-river-washington-dam-removal https://www.outsideonline.com/2413366/steelhead-fish-return-... was posted yesterday about dam removals in the Pacific Northwest, and the subsequent return of steelhead trout to the rivers.

adrianN 6y ago

There is no fully "green" power, but almost everything is better than climate change.

Cthulhu_ 6y ago
I think "green" is not the right moniker here; "renewable" covers it better I think. With (with my limited knowledge, naive opinion) solar panels and wind farms having less of an impact than hydro dams.
- rocqua 6y ago
  Judging only on 'renewable' the ecological impact of a hydro-electric dam doesn't matter. The energy extracted here is renewable. Because rain will keep falling and thus the reservoir will keep being filled. The fact that it damages an ecosystem does not count there. Moreover, the fact that dams damage an ecosystem have very little bearing on the global-warming effects of dams. Whilst I do not want to say that ecological damage is not important, I think it is an issue that 'green' and 'ecological' have dual meanings. The current main usage being "Does not cause greenhouse gasses" with a less used original meaning of "Is good for the environment". This causes a lot of friction between people who use the same words but care differently about environmental impact beyond global warming. It used to be that caring about the environment was a fringe movement in so far as getting political change. Global warming has gotten 'being green' on the political agenda. But it sometimes feels like some of the more extremist green ideas have snuck into the greater public discourse under the guise of being 'green'.

Retric 6y ago

Many dams are going to exist due to flooding, irrigation, etc. Extracting hydropower once you have already decided to build a dam is as close to fully green as it gets. That said, there are many low head dams built exclusively to extract power, and many of those are no longer serving a useful purpose.

philshem 6y ago

The standard term is “renewable”, and yes, there are environmental concerns for any type of human-engineered energy production. For run-of-river hydro power, one mitigation is fish ladders: https://en.wikipedia.org/wiki/Fish_ladder https://en.wikipedia.org/wiki/Fish_ladder

BurningFrog 6y ago

I wish people would distinguishing destroying eco systems from changing them. A dam changes the eco system, but nature forms a new balance around the new geographical feature that is not inherently worse, just different.

epx 6y ago

Sometimes there are positive unintended effects. Near my city, there are a number of small hydro plants and dams, built before a grand national syncrhonized system was ready. While the dams were built inside very preserved forests, so there was initial damage, the surrounding area (tens or hundreds of sq. km) were put under protection to guarantee the water supply, so no reforestation, no agriculture, etc. Now even the surrounding areas are in better shape today than in the 1960s when the dams were built. Of course it helps the individual size of each plant is small (tens of MW, tops).