[HN Gopher] The largest dam-removal in US history
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The largest dam-removal in US history
Author : pseudolus
Score : 77 points
Date : 2021-01-01 03:29 UTC (19 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| AdamJacobMuller wrote:
| I think it's an unfortunate omission from this article, but, with
| every question like this you have to consider things on balance.
|
| Everything you do to generate power will have some impact and
| conversely some benefit.
|
| They talk a lot about the impact here, but, not at all about the
| benefit.
|
| All of the dams on the Klamath River produce a combined power of
| only 169MW (and this isn't even removing all of them, I think its
| actually removing not even 40MW of power generating capacity.
|
| Again, you have to consider everything on balance. This is an
| absolutely pitiful amount of energy. For example, three gorges
| produces 22,500 MW of power.
|
| Common designs for self-contained PORTABLE nuclear reactors
| easily outclass the entire generating capacity of these dams.
|
| The balance of impact vs benefit on these is incredibly tilted
| against these projects continuing to exist.
|
| Also, Chinook is delicious and anything which means more lox is a
| win in my book.
| sjdbdjd wrote:
| You are comparing the power output of a damn that displaced
| some fish to one that displaced tens of millions?
|
| Doesn't seem very proportional
| AdamJacobMuller wrote:
| I wasn't trying to compare the two and make a judgement on if
| 3 gorges is worth it while these aren't, I'm merely saying
| that 3 gorges is so much more massive in scale.
| bmitc wrote:
| > Also, Chinook is delicious and anything which means more lox
| is a win in my book.
|
| The salmon isn't for you. It's for the orcas who are literally
| starving.
| seltzered_ wrote:
| Honestly this framing just makes me wonder about what the
| impacts of three gorges dam has then, or it's risks.
|
| It's more complicated than just finding balance vs. impact on
| dam power level, it's the other things introduced by human
| population that isn't aware or engaged with the local ecology.
|
| To ramble aloud, Recently tire dust was linked to salmon
| getting sick (
| https://www.nytimes.com/2020/12/03/climate/salmon-kill-washi...
| ), and in talking with people in the northwest home
| construction around urbanism/single family home suburbs over
| the past 30 years has hugely impacted the pacific northwest
| ecology.
| mschuster91 wrote:
| > Common designs for self-contained PORTABLE nuclear reactors
| easily outclass the entire generating capacity of these dams.
|
| None of these designs has been turned to production yet, and no
| one has solved the waste storage question.
| dredmorbius wrote:
| Nameplate capacity (power, in MW) isn't the only consideration
| in electrical generation, but total generation (energy, in
| MWh), dispatchability, cold-start capability, pollution, other
| impacts, maintenance, storage, accident risk, waste storage,
| and other factors.
|
| Even smaller hydro sites are valuable in that they represent
| very raapidly dispatchable load --- a dam's turbines can be put
| online or taken offline in seconds to minutes, where other
| sources (notably conventional and nuclear thermal power)
| require hours to days to make large cycling changes.
|
| Solar and wind rely on incident available energy, and are _not_
| deployable at operator discretion, though balancing over the
| grid or via storage, or dispachable _load_ , may be possible.
|
| Hydro banks power in the form of impounded water. And with
| relatively simple moddifications offers 90%+ efficient pumped
| hydro storage capabilities.
|
| The downsides are the large ecological impacts noted in the BBC
| article, sedimentation (a particularly large problem on the
| silt-heavy Colorado River), as well as some risk of structural
| failure, though the US record on this is generally quite good.
|
| With many thousands of dams, there've been a handful of major
| failures. Planning, alerts, and response generally eliminate of
| minimise deaths, though disruption from evacuations, or
| property damage can still be substantial. Long-term
| consequences spanning centuries, as with nuclear failures, are
| not a factor, even in utterly catastrophic failures, largely
| experienced outside the US.
|
| I'm not defending the Klamath hydro facilities, only noting
| factors.
|
| Your obsevation that there are both benefits _and_ negative
| impacts is true of any technology or technological
| intervention.
| rhodozelia wrote:
| The article made it sound like they would lose less than 8% of
| their 2200 MW renewable generation for a reduction of less than
| 176 MW. Maybe the article confused the total generation from
| the 8 plants with and the 4 being removed.
|
| They estimated 450 million to add fish ladders and rehabilitate
| the facilities for the next 100 years. If it was $450 million
| for 170 MW $2.6 million / MW is pretty cheap construction cost.
| I am surprised that it isn't an attractive investment
| AdamJacobMuller wrote:
| Correct, so, 176MW is the power generation for ALL dams on
| that river. They are only removing 4 of them of which I think
| only 2 produce power and I can't find exact figures on the MW
| output of each of them. 169 was an upper bound and seems VERY
| small.
|
| 450M was the cost of removal according to the article, not
| the cost of adding new fish ladders?
| rhodozelia wrote:
| >This is because to renew the operating licence for these
| dams, its ratepayers would have to foot an approximately
| $400m (PS308m) bill for upgrades to ensure compliance with
| legislation (including the installation of costly fish
| ladders at each dam that would enable migration).
|
| Upgrading the dams cost $400m.
|
| >Overall, little will be lost in terms of renewable energy
| generation: the dams represent less than 8% of PacfiCorp's
| 2,208 MW current renewable generation capacity,
|
| [1] indicates that you are correct and 7 dams produce 169
| MW. so indeed these dams produce a relatively small amount
| of electricity.
|
| 1: https://en.wikipedia.org/wiki/Klamath_River_Hydroelectri
| c_Pr...
| oefrha wrote:
| > three gorges produces 22,500 MW of power.
|
| Correction: 22,500MW is the installed capacity, i.e. what the
| generators are capable of. It only reaches about half capacity
| on average, going by the numbers listed in the Wikipedia
| article (101.6TWh in 2018 => average ~11,600MW).
| [deleted]
| stjohnswarts wrote:
| The problems is they aren't building any power to deal with the
| decrease and no one is building nuke plants that haven't been
| in the works for 15+ years. I all for this if they want their
| rivers back though, but we can act like there won't be
| consequences.
| csomar wrote:
| Solar production in the US is growing: https://en.wikipedia.o
| rg/wiki/Solar_power_in_the_United_Stat...
|
| No need for them to produce electricity, they can trade fish
| for electrons.
| Rebelgecko wrote:
| Unfortunately, the usefulness of solar is limited by our
| energy storage capabilities. Water is one of the best ways
| of fixing this (either to supplement solar, like running a
| hydro dam on a cloudy day, or as a direct storage system,
| where excess electricity is used to pump water uphill so
| that the potential energy can be harvested later)
| Retric wrote:
| Peaking power plants actually cost more per kWh than
| solar backed battery storage. However, until we install
| enough solar that's a pointless exercise as simply
| directly using solar energy is more efficient and there
| isn't a regular surplus to capture.
|
| The economics of this get really interesting. In a
| largely solar grid, 1 axis Solar tracking systems add
| production in the morning and evenings, thus offsetting
| the need for a lot of battery storage. However, we aren't
| currently using significant battery storage so that isn't
| worth it yet. Similarly shipping a surplus East / West
| time shifts it, but we don't currently have that surplus.
| csomar wrote:
| The way I see it, we haven't worked had on energy storage
| capabilities. We optimized for cellphones and Laptops,
| and these cover most of your day or more now. For homes,
| the market is still no that big, because batteries are
| expensive and electricity is widely available.
|
| As we move to solar, electricity will become very cheap
| in the day and very expensive at night. This will create
| the required capital to create storage solutions in
| houses and factories. Also you don't need a portable
| battery when installing it at home, so I think the cost
| could be reasonable.
| maxerickson wrote:
| Lots of dams are flood control projects that also produce
| electricity.
| redis_mlc wrote:
| The Chinese Three Gorges Dam is an electricity project (that
| benefits one family), and doesn't do flood control (it's 100'
| too short. The reason is that if it was the correct height,
| it could flood a major city upstream.) :)
| AdamJacobMuller wrote:
| True, that's another possible item in the benefit column,
| but, it also creates risk of a catastrophic failures like
| Michigan and almost-orville.
| paledot wrote:
| Indeed. This is why hydro shouldn't be considered green energy.
| (That, and the methane reduced when hundreds or thousands of
| hectares of living, breathing land are flooded and decompose in
| an anoxic environment.)
| 908B64B197 wrote:
| > This is why hydro shouldn't be considered green energy.
|
| Minuscule emissions when it's built that are amortized over a
| 50 year lifespan qualifies as very green in my books. The
| idea that it's not green anymore is absolutely ridiculous.
|
| I sometime wonder if environmentalism greatest threat
| isn't... environmentalists themselves!
| AdamJacobMuller wrote:
| Does anyone consider hydro as green anymore? Nuclear has far
| less impact.
| stjohnswarts wrote:
| Very few people consider nuclear power as "green". It's
| better than almost all the alternatives but those arguments
| don't work with you average citizen any longer so nuclear
| power is plateaued for the forseeable future in Western
| nations.
| eigenvector wrote:
| Well said. To paraphrase Wade Davis, the question is not hydro
| or no hydro but where, how much and for whose benefit. Many
| dams produce very little electricity and can be removed with
| minimal impact to the cost or carbon intensity of our power
| supply.
|
| We should not conflate dams that are integral to the power
| system like Grand Coulee with those that are insignificant.
| [deleted]
| labster wrote:
| > On 17 November 2020, a new agreement was signed between
| PacifiCorp, the Yurok and other stakeholders to facilitate the
| dams' removals. Should federal regulators approve, the project
| will begin in 2022, with the demolitions slated for 2023.
|
| These damn removals take too dam long. The Matilija Dam has been
| waiting for over 20 years and has only been symbolically
| demolished. Everyone agreed it was a good idea to remove it in
| 1998, and it's still standing.
| ars wrote:
| According to Wikipedia the issue with the Matilija Dam is that
| there is so much sediment built up behind it that they can't
| figure out how to remove the dam without causing a disaster.
|
| There are various proposals, but it seems none are good enough.
| rhodozelia wrote:
| It is odd that dams don't incorporate a means for sediment to
| continue its path downstream. If there were a channel that
| ran the length of the reservoir that was narrow enough it
| would Keep the velocity of the water high enough that the
| sediment wouldn't settle out. It could then be run through
| the turbines, admittedly causing more wear, or allowed to
| settle behind the dam in an area with a sluice gate that
| could be used to flush sediment out. Probably much easier
| said than done so the problem has just been universally
| ignored.
| eigenvector wrote:
| From a hydrotechnical perspective, it's a feature not a
| bug. You do not want sediment going through your turbines.
| Suspended sediment is a major maintenance issue for run of
| river hydro plants.
| rhodozelia wrote:
| Would you rather have to overhaul a turbine every year or
| have no fish?
| rhodozelia wrote:
| I acknowledged that sediment suspended in water moving
| through the plant causes wear and suggested designing
| such that it would be deposited in front of a sluice gate
| to allow it to be flushed without going through the water
| conveyance plant and the turbine.
|
| I think the sediment building up behind the dam is a bug
| and not a feature 1) the reservoir fills up with sediment
| reducing the volume of water that can be stored and the
| amount of stored energy 2) according to the article,
| depriving the downstream reaches of the river of sediment
| is detrimental to the ecosystem. 3) for run of river
| plants as you have indicated the sediment builds up
| behind the intake structure and once that volume, which
| is often quite small for run of river plants, is full it
| has no choice but to go down the penstock and through the
| turbine anyway, and depending on the abrasiveness of the
| sediment and velocity of the water it can be extremely
| effective at removing metal.
|
| Clearly it is better for sediment to continue moving
| downstream past any dams or intake structures. Maybe some
| kind of dredge system / conveyor system would be another
| option.
| stevesearer wrote:
| For those interested here is an image of the sediment taken
| in July 2020.
|
| https://www.instagram.com/p/CCeyR3hFWJh/
| Doctor_Fegg wrote:
| Another aspect of dam removal (though not on the Klamath River)
| is that dams with locks facilitate level pounds and boat
| navigation.
|
| Several locks in the US have been removed or closed in recent
| years, making navigation impractical. It seems strange from a UK
| viewpoint: here, many formerly derelict canals and rivers have
| been restored to navigation over the last 60 years, and work
| continues.
|
| Right now, for example, fish passes are being installed at the
| locks on the River Severn - the idea of removing the locks
| entirely would be unthinkable. (Though, in a sign of how
| attitudes have shifted, the once-popular notion of building more
| locks to extend navigation further upstream has died a death.)
| reportingsjr wrote:
| After about five years of researching UK wildlife/natural areas
| I have come to the conclusion that the UK should be considered
| one of the worst examples of how to manage nature.
|
| It is amazing how much Brits insist on destroying their nature
| rather than working with it, truly a sad thing.
|
| Just look at the total destruction of basically all of the
| chalk streams, the insane struggle to reintroduce beavers
| (beavers! Not even that crazy of an animal to bring back),
| badger culls, grouse moor monocultures for hunting, nearly
| complete destruction of any native woodland, the list goes on
| and on and on.
|
| The UK really needs to take a step back and look at what
| they've done to their nature.
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