In a major reversal, the world bank is backing mega dams (2024)
47 comments
·July 21, 2025Rover222
landl0rd
Hard agree on pumped hydro and other forms of grid-scale storage, but can you understand concerns around batteries? There are environmental ones on the mining/metals side, but producing and disposing of them in a clean manner is often hard. Getting them from anywhere save mostly china is hard (if you want large, dense, affordable, and grid-scale options) and depending on somebody who's nobody's geopolitical friend is probably a bad idea.
Ditto for the panels themselves.
bryanlarsen
> but can you understand concerns around batteries?
No I can't. Just recycle the batteries, and you've solved both concerns in one go. Lead acid batteries have a >99% recycling rate, the economics for recycling EV & grid storage batteries are even better.
aDyslecticCrow
"Just Recycle the batteries" is a massive understatement of the effort involved. The economics of Recycling ev batteries is autrocious. (They're glued into the frame of the car (differently for each model), needing manual dissasembly to not risk fire)
It took 20 years of standardisation and effort to raise lead acid batteries to 99%, and they're as simple as batteries get. Large scale recycle of litium batteries (including the cobalt and nickel) requires changes in how batteries are made to be (either or both) less energy dense and more expensive.
Pumped hydro is the best bet for gridscale. And i'm hoping sodium batteries roll out for EVs within the near future.
gonzo41
Sand batteries provide a very nice scalable solution IMO. https://polarnightenergy.com/sand-battery/
bryanlarsen
Hydro is a great complement for solar, you can decrease flow when the sun is shining, and increase it when it isn't.
aDyslecticCrow
Very situational on where it can be used, and requires some very careful cost calculations.
Ignoring the local effects of their construction, a damb breach is one of the worst man-made disasters possible. Mantinence and error margin must be very very carefully accounted for. There is a reason the world bank stopped funding them, and it wasnt purely enviromental. (Some badly managed projects led to expensive and dangerous situations)
So when relevant it's most powerful energy source avalible. But the list of preconditions and caveats is massive.
Nition
Yep, and if you can pump water back into the lake with excess solar power when the sun in shining, you now have a giant storage battery as well.
Ancalagon
Please can we just get back to building nuclear
Kon5ole
The solar panels installed in China during the past 2 years produce as much electricity as all of their nuclear plants combined.
Finland spent 18 years and 11 bn euros to get 1.6 GW of nuclear, the US spent 7bn in subsidies and got some 20 GW of solar in 2022 alone.
Countries going for nuclear will wait decades to get the same power that solar can add in weeks.
Nuclear basically makes no sense at all in 2025.
(For nighttime use dirt-cheap batteries and natural gas now, even cheaper batteries and generated hydrogen gas later).
geysersam
But what to do in Finland during the winter months? I'm massively pro solar, and I'm sceptical of nuclear, but this seems like a problem to me. Batteries work well on shorter time scales but not over the entire year.
olddustytrail
Finland's electricity production is already 95% non fossil fuel, so you don't need to worry about them.
umvi
> The solar panels installed in China during the past 2 years produce as much electricity as all of their nuclear plants combined.
Because it doesn't have very many nuclear power plants relative to its size? France has the same number of nuclear reactors as China despite being a much smaller country.
I'd argue 50-60 nuclear power plants having the same energy output as millions (billions?) of solar panels is a win for nuclear - it's much higher energy density, much smaller environmental footprint, much smaller infrastructure investment, etc.
debesyla
I would add that also a lot of solar power is funded by small capital (homeowners). There is no real way for small capital holders to fund and gain profits from nuclear energy, and installing wind or water turbines are not realistic at 99% of homes.
aDyslecticCrow
Great comparison to use the most delayed neuclear power plant constrution in human history to extrapolate an argument. Really fairly done.
Japan builds them in 3 years. USA took about the same during the heights of its use.
cyberax
And at night, nuclear power plants produce infinitely more power than solar. Same during winter months.
Solar simply can't work alone for northern countries without insane amount of batteries. We're talking about having a MONTH of supply in reserve for Germany. It's probably even worse for Finland.
marcosdumay
Make nuclear cost-competitive and people will start building it.
notepad0x90
I thought it was cost-competitive with something on the scale of mega-dams and takes about as long to finish too. Except unlike dams, you don't disrupt river flow and cause water-rights disputes (and potentially wars).
janice1999
> Except unlike dams, you don't disrupt river flow and cause water-rights disputes (and potentially wars).
The water requirements of nuclear power stations cooling systems can cause significant issues. The discharge of heated water back into rivers and the sea is also a major problem.
marcosdumay
The unit economics of dams get more and more competitive when their size increase.
So, hell no, nuclear is not competitive with mega-dams. It's not even competitive with small dams.
colechristensen
Nuclear is cost competitive if you have a reliable cadence of building plants and if folks get out of the way of location permits and waste storage and people can actually make decisions about them without endless debates and lawsuits. The problem is one-off designs and the decades long gap between project inception and when investment returns start coming in. As opposed to solar where I could order a few panels and accessories online and start producing energy within a week. Obviously larger solar projects take more planning but if you've got a roof, a credit card, and an electrician on hand you can start producing electricity or expand your production in a very short time achieving break even in a few years.
zahlman
It was cost-competitive before it faced ridiculously unfair regulations due to being so easy to fear-monger about.
daymanstep
There is a finite amount of hydro in the world. They will run out of viable dam locations pretty quickly at this rate.
Animats
All the good sites were used by 1940.
The ideal big dam is Hoover Dam. Large, deep canyon in a desert. Narrow, deep canyon dam site. Hard rock geology. No major towns or agricultural areas in the area to be flooded above the dam. That's the best case.
Most later dams are at worse sites.
eunoia
For the curious:
Cadillac Desert is a great history of American dam building and the Bureau of Reclamation
tomrod
In which continent?
bryanlarsen
$80B is buying 40MW of hydro. What would that get you for nuclear? 4MW?
qwe----3
Looks like at least 30GW
https://www.reuters.com/sustainability/boards-policy-regulat...
jasonwatkinspdx
If we use Vogtle as a cost benchmark you'd get roughly 5 GW (note you typo'd units to MW).
erentz
Given these projects will be overseas we shouldn’t use the extreme outlier of Vogtle in the US as the benchmark.
ginko
It’s 40GW of hydro
V__
Nuclear just isn't economically viable. Maybe fusion someday.
qwe----3
Tell that to China
bobthepanda
China has been building them at a relatively lukewarm pace compared to its solar and wind expansion
> China installed 1GW of nuclear last year, compared to 300GW of solar and wind, Mr Buckley said.
https://www.abc.net.au/news/science/2024-07-16/chinas-renewa...
forrestthewoods
> isn't economically viable
That is not an intrinsic truth. We have chosen to make it economically unviable.
Most things get cheaper to build with time. Nuclear is an outlier where it used to be affordable and now it isn’t. That’s insane.
permo-w
why is it different like that?
bryanlarsen
Nuclear has never been particularly affordable. It's always been more expensive than coal or gas, even in France in the 70s-80s and China in the 2010s.
Here's how much it cost to build nuclear in France during its golden age: https://ifp.org/nuclear-power-plant-construction-costs. Adjust for inflation and draw your own conclusion.
China's nuclear costs are more opaque, but are estimated at $3B per GW. Again, not competitive.
aaron695
[dead]
We have cheap fusion. A giant reactor in the sky. Solar should be massively scaled, along with battery capacity and pumped storage. China is crushing in this.