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Comment by droffel | Hacker News Reader

I've been hearing the same line about nuclear plants taking decades to be built for decades, as if its a valid dismissal. As the saying goes, the best time to plant a tree was a decade ago, the second best time is now. We should be scaling up our nuclear capacity.

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Any effort spent building nuclear for the 2040s is effort that could build 5x as much solar and wind for 2025.

Plus transitioning to nuclear just builds another set of kochs and saudis.

Plus it makes your entire economy beholden to one of China, Russia, France, or the US.

Plus it just kicks the can down the road. If you consider direct thermal forcing. We are exactly where we were in the late 19th century with greenhouse gases. There is no option but to transition to a steady state economy, and starting a bunch of projects that only pay off if you use as much energy as possible from them (and even then, solar + storage will be a fraction of the cost by the time they open) isn't the way to get there.

Plus those same five countries won't even let half the world have nuclear power plants.

Plus the world's uranium reserves won't actually last very long if you carry on with exponential growth (doubly so without reprocessing and breeding).

Then there's all the usual risks people mention.

The solution is the same as it has ever been. Degrowth, stopping waste, and renewables.

Solar and wind are nice, but they don't solve the base load problem. They aren't consistent enough to operate as base load on a power grid. They are certainly convenient for maintaining peak load, but without solving the energy storage issue in parallel to the added capacity, we need alternatives.

Spreading out production units of a mix (wind, solar, hydro, geothermal...) is key. For the sole wind: https://www.imperial.ac.uk/news/180592/european-cooperation-...

Then comes storage, curtailment, and backup (always necessary: fossil-fuel plants always produce around 9% of electricity in fully-nuclearized France).

Moreover backup is now provided thanks to gas turbines, and we know to run them thanks to hydrogen (clean), which can be green hydrogen (cleanly produced thanks to renewable sources overproduction).

>Spreading out production units of a mix (wind, solar, hydro, geothermal...) is key.

Sure. Let me just build hydro dam where there's no hills and dig some geothermal where's no geothermal activity and we're all set!

Laser drilling is not far from being viable. With it you can put geothermal anywhere.

That has yet to be proved viable. It might be competitive, it might not, we'll have to see.

At any rate you could build nuclear faster than that will take to be ready for market in the best case.

There is no need for each location to deploy each and every type of production unit: each region has its own geography and preferences.

Those benefiting from huge potential for hydro, offshore wind or solar (deserts...) are at an advantage. Those benefiting from a low production time-profile correlation with most other ones also are blessed.

Those totally unable to deploy anything probably don't need huge amounts of energy or are rich to the point of already importing it (is there a counter-example?).

Solar and wind simply can not supply the energy needs in large sections of the EU.

If Europe can continue to buy cheap Russian gas and oil and use it as they have done in the past then 5x as much solar and wind for 2025 sounds great. That was the Great Plan of the green movement in Germany. In 2010, 2020, 2030, 2040, 2050 or a time after that green hydrogen will become cheaper than Russian gas and oil and then this plan will be completed.

If however Europe can't continue to burn gas and oil when demand exceeds supply because of the weather, then there is a major problem that is going to need fixing in a very expensive and time consuming way. If green hydrogen don't drop in price and no other storage solution can arrive to become cheap than gas and oil, then the climate change goals won't be achieved.

To add to the problem in northern Europe, the locations for hydropower is practically already at maxed utilization. They are also quite old and with large maintenance debts. They are also is causing extinction of several species, and fixing that would cost prohibitively much money, and the solutions will reduce outputs.

The thing is, 5x solar and wind sounds great but if I can specific the time and space for it, I would make a great profit of trading 5 units of energy for 1x at a different space and time. The price difference in northern Europe can be a factor of 10 or even higher between low and high. 5 kwh worth 3 cent each is worth much less than 1 kwh worth 40 cent.

Solar farms take six months. Wind farms 2-3 years. Pumped storage takes ~5 years and theres no shortage of locations: https://www.sciencealert.com/scientists-spot-530-000-potenti...

A non nuclear mix is also cheaper and isnt uninsurable without a catastrophe liability waiver.

The best time to build a nuclear plant is 40 years ago.

Pumped storage is cool but way more situational than you think

I have read several of those studies with an automated workflow to find suitable pumped hydro/wind/solar and they consistently miss local awareness. They often use deeply inaccurate land cover classification when the simple usage of open street map could have helped, and for hydro they underestimate the recent local opposition to destroy a village to build a dam.

There's a lot of low hanging fruit in the hydro landscape that people miss. I have a rivulet that runs near my house. It has weir dams at a few locations on it's path down our mountain, IT wouldn't be that hard to extract energy from the constant flowing water there to feed into the grid. There are turbines that exist to extract energy from a meter high head of water.

Everyone thinks about power like you need one big dam, or one big plant (coal or otherwise). There's a lot of small fast flowing streams that have potential to create extra energy.

I think hydro needs to be reimagined. IT always need to flood valleys to be in the mix.

I dunno, patching up every little creek and flow of water we can find sounds to me like hydro just can't generate enough energy.

That really depends on what percentage of water's potential energy is expended in small creeks and the like vs big rivers.

I actually have no idea how to estimate that. Anyone have a good estimate on that? Intuitively, I'm thinking that most of those rivers are fed by many small streams, so it would be approximately equal. I'm entirely unsure of that though so treat it as having huge error bars.

The problem becomes one of how spread out the energy is.

Sure the water in that creek might be falling hundreds of meters, or even kilometers, but without a dam the height differential at your generator is only going to he a few metres at best. Enough to power the lighting, fridge, and washing machine in the houses that the creeks happen to run by, but not much else.

With the advent of long lasting perovskites and (hopefully) some less polluting battery technologies you're not even better off cost-wise.

You might be able to do something with a long pipe parallel to the creek to get more head, but then you're going to spend a lot of your energy on wall friction unless it's very wide.

> Sure the water in that creek might be falling hundreds of meters, or even kilometers, but without a dam the height differential at your generator is only going to he a few metres at best. Enough to power the lighting, fridge, and washing machine in the houses that the creeks happen to run by, but not much else.

Could be, but that's a bunch of stuff you don't have to power with the existing system. Given how many creeks there are, that seems like it could really add up.

> With the advent of long lasting perovskites and (hopefully) some less polluting battery technologies you're not even better off cost-wise.

That's fair. I've learned in my life that I don't have a good intuition for what the costs of large infrastructure projects are.

It would also have a tremendously negative impact on the local environment. Even tiny dams cause big disruptions to the riparian ecosystem.

Surely theres is wildlife that depends on the speed of at least some of these bodies of water, right?

Yeah in this example, the water is never stopped. Not even the flow rate, It's just held back for a moment to create a convenient potential energy situation. This https://www.youtube.com/watch?v=Bhyi1DjGti8 Is something that could be built near a bus stop near my house and not negatively impact anyone outside of the initial construction.

Who is going to run all the little dams and turbines, though? And how would it ever be cost effective to do so? There is so much maintenance on small lakes that don’t even have a turbine (mainly dealing with silt, which accumulates steadily and is hugely expensive to remove).

Pumped storage is hard because you need a lot of space on a hill for a reservoir. Perhaps we can turn lake mead into a giant pumped storage project with a bunch of solar installed over it to limit evaporation. Then use wind, solar, or even nuclear to fill it (but that’s a lot of water that farmers might want for their fields, again, limiting evaporation is important).

A few example large solar plants in the US seems to have ~500MW capacity, ~30% capacity factor (so ~200MW effective capacity), and taken 2-5 years to build [1][2][3].

A nuclear plant will probably have multiple 1GW reactors, with very high capacity factors. I think your numbers are very optimistic.

1. https://en.m.wikipedia.org/wiki/Solar_Star

2. https://en.m.wikipedia.org/wiki/Desert_Sunlight_Solar_Farm

3. https://en.m.wikipedia.org/wiki/Topaz_Solar_Farm

Building a nuclear power plant today is assuming storage for solar and wind will not be figured out within 50 years, allowing you to sell electricity at todays price for at least this time. You can see why no one wants to take that bet. It's over, it was already over 10 years ago, stop trying to fit every crisis around a "nuclear was unfairly maligned" obsession.

See you in 10 years, when we are still arguing about nuclear taking 10 more years and still dependent on fossil fuels.

The best time to plant a radioactive tree in your yard is never.

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