As I understand it renewables and batteries have their own environmental impacts that can't be ignored. When comparing nuclear with renewables the impacts start to show nuclear as at least a good contender as the future power source. But large scale fusion might drastically lower energy costs. That could enable things like carbon capture.

"Can't be ignored" meaning what precisely? This is a phrase that sounds like pure FUD, and despite spending a lot of time trying to quantify where this supposed environmental damage comes from, I haven't been able to find anything of substance.

Similarly, I don't think there's much reason to believe that fission nor fusion will be able to compete with renewables on cost. Even if fusion is a completely free source of heat, you still need to convert heat to electricity with a steam turbine and it won't be long before renewables are cheaper than a steam turbine and cooling infrastructure on a free heat source.

People have this strange faith in fission and fusion as being cheap, at some point in the future, but nobody can ever explain why it will be cheap. What is the mechanism that could drive this along?

Solar is the current cheap electricity that will drive carbon capture. There are even startups that have plans for using atmospheric carbon capture to generate synthetic fuels, that plan to be profitable with the current cost curves of solar and the rest of the industrial process.

The world is a very different place than 20 years ago when it comes to technology, and I think it's time to re-evaluate the potential promise of fusion as an energy source. I don't think it has much promise for terrestrial power, but as always, I would love to have my skepticism conquered.

Can't be ignored means we have not found a non destructive means of energy production yet. Waste from current renewables will build up. We still need to be on the look out for better technologies for the future. That is not to say they are not a huge leap forward but it does have to be considered.

I don't understand this. What problem do you foresee happening?

You may as well say that we can't build any more houses, or make more clothes, because of the waste. If the rate becomes a problem, in some way, we will recycle the necessary parts. But unlike, say, coal ash, the waste is easy to handle, and easy to repurpose if we find the need to.

> won't be long before renewables are cheaper than a steam turbine and cooling infrastructure on a free heat source.

That's an absolutely extraordinary claim. How could a wind turbine ever be cheaper than a traditional generator and turbine, since it consists of a generator + rotor + massive tower in a remote location with a very low utilisation rate?

You know you cannot just assume a trend will continue infinitely, especially if the conclusion is so non-sensical.

The steam turbine has to endure super heated steam, requiring very specific materials. Steam turbines also require boilers, cooling, etc. Wind turbines have the potential to require far less in terms of the input materials. And with solar, who knows how efficient we can get with that!

We have been optimizing steam turbines for more than a century, but are just barely getting started on optimization for wind and solar. So far, the rate of improvement hasn't start to slow at all, so I'm fairly confident that due to greater simplicity, wind and solar will end up being less costly than steam turbines. Predicting the future is tricky business, but in the 90s it would have been foolish to think that semiconductors wouldn't get better for more than just a few years. And we are in a very similar place with wind and solar techs now as we were with semiconductors in the the 90s.

Mist of this post is badly wrong, wind turbines are essentially a close cousin of steam turbine, and are massively more expensive per Mw of power. A single steam turbine can generate a GW and will weigh less than a wind turbine that generates a MW, a thousand time less!

We run steam turbines as high pressure because that gives us efficiency, not because we have to.

"he rate of improvement hasn't start to slow at all, so i am confident"

You have no evidence, so you are confident?

Also airdinamics are well understood, there are no miraculous effficiencies coming to wind turbines

You don't even address some of the core points: a GW of steam turbine is going to require massive cooling infrastructure that wind turbines do not require.

The learning rate will not stop overnight with wind turbines; there is more than enough research and industrial improvements that are in the works that we will start to see a slowing of the learning rate before it suddenly stops.

Also, airdynamics and not well understood as it relates to wind farms, and new research comes out all the time to improve efficiency of future designs.

For somebody who's claiming that the other person is not providing any evidence, you are operating without any links, only with certainty that I must be wrong about predictions that I admit are tricky to make.

The real issue with nuclear is not the waste, but the time it takes to build the reactors. We don't have enough time left before we irrevocably fuck up the climate. Solar and wind can be brought online much quicker.

Which fossil fuels are "less bad" for the climate? They're all very bad.

Obviously old coal powerplants are the worst, but there's more evidence every year that the allegedly "clean" natural gas is nowhere as clean as advertised once you account for fugitive methane emissions that in practice are largely untracked. And flooding the market with cheap fossil fuel like methane as a "transition fuel" – another marketing gimmick – will only delay the transition to renewables for obvious economic reasons.

I'm not optimistic about big shots like fusion, but small modular nuclear reactors for example could be operating relatively soon if only we had the desire to go in that direction.

> Obviously old coal powerplants are the worst, but there's more evidence every year that the allegedly "clean" natural gas is nowhere as clean as advertised once you account for fugitive methane emissions that in practice are largely untracked. And flooding the market with cheap fossil fuel like methane as a "transition fuel" – another marketing gimmick – will only delay the transition to renewables for obvious economic reasons.

None of this makes nuclear, and fusion in particular, necessary in order to avoid a "looming energy crisis"? That's what we're talking about. If we wanted to have better emission tracking and/or carbon capture for natural gas we could probably do it, I'd guess, and it's still not clear natural gas generation is required at all in the face of improving renewables and storage.

You know, what's not clear at all is that renewables will ever be cheaper than fossil fuels outside of a minority of markets. You're putting a lot of weight on that prediction but despite all the recent progress on costs, if that was going to happen anytime soon, climate change would largely solve itself. Wouldn't that be nice.

Small modular nuclear on the other hand could be economically feasible in places that don't have the money to pay extra for renewables but still want to drop their GHG emissions.

I'm not claiming that renewables have to completely replace fossil fuels (see my reference to carbon capture), or that they even need to be cheaper (fossil fuels could become artificially expensive by, eg, carbon taxes). I'm questioning the assertion that nuclear is essential, which is what was claimed by the comment I replied to.

Nuclear might be nice to have, might be better for various reasons, might be lots of things. But is it absolutely required "to solve the looming energy crisis of the 21st century while still maintaining the same standard of living for everyone"? That's my question.

>will only delay the transition to renewables for obvious economic reasons.

If you want more renewables then you need a more flexible grid. All that crappy coal baseload clogging the grid needs to disappear and make space for renewables. Gas plants are cheap to build but expensive to operate. They will be mostly used when there is a temporary shortfall of renewables. They are also necessary for power to gas if you actually want to reach 100% renewables.

The fundamental difference between nuclear and any other source is energy density. It boggles ones mind that your can replace burning 14 thousand tonns of coal _every day_ with something that needs to be refueled once a year.

Sure, but energy density (which is essentially hypothetical in the case of fusion, because we don't have fusion power) has got very little to do with the assertion that nuclear energy (and fusion in particular) is the only way to avert a looming energy crisis?

nuclear energy density is derived from e=mc2, so fusion/fission are in the same ballpark.

Current accepted way is to build solar/wind and redesign grid to deal with intermittency. Solar and wind are even more energy diluted than fossil fuel, they take 500 times more space, more land out of nature/alternative uses.

Nuclear has already demonstrated that it can decarbonise industrial economy up to 80%, see France. and they did it just in 10 years.

This is bascally the reason i think this is the way out of crisis

All for nuclear, but the amount of land used is higely exadurated. It is actually totally trivial if you run the numbers.

In reality >90% of worlds valuable land use is farming. Factories, cities, houses, etc. all hardly matter.

Well, one example. I live in Singapore, and for it to become energy independent, it would need a square kilometer for a nuclear plant. To achieve the same with solar, you need to pave the whole country with solar panels.

Besides, to make these solar panels you need to spend energy too. and EROI for advanced solar is about 20, where for nuclear it is 80+.

I think people should stop using nature when they can get the same/better results without using it/using several orders of magnitude less of it.

I view renewables as energy farming, and city-states like Singapoure, lixemburg, etc. Are not very suitable for either form of farming :) for most countries the calculus is very different. UK has been developing sea based wind turbines quite succesfully, thats something that could work for singapore.

I view nuclear as a bit of a lost cause to be honest, they take long time to build, cost a lot upfront, you need a lot of expertise around them, and they would require a miracle of PR. It does not appear likely that countries that do not have an established nuclear industry will suddenly become nuclear powered. Thats just the way things appear to be heading, and its a shame.

Besides, don't underestimate the infrastructure needed to refine fuel, manufacture fuel rods, deal with waste, etc. If you outsource all of that, you are not terribly energy independent.

I think the only hope for nuclear industry is small modular reactors, and that's only if a massive amount investment comes through.

What I meant is ofcourse de-carbonise economy, Singapore can't be energy independent in meaningful sense as it does not have fuel sources of any kind. And solar/wind do not count as there could totally be still nights.

I frankly dont understand how an energy source that can shift from 100% to 5% capacity on its own whim, independent of its user's needs could get so much attention and considered viable replacement for something predictable..

There was not a single economy decarbonized on solar\wind, even for those that tried really, really hard (see Germany). And we have example where it worked, in short 10 years.

There are countries still that can build nuclear on time and on budget - see South korea for example. Wonder why they don't get all the orders for urgent decarbonisation needs.

> There's plenty of oil, gas, and coal out there still.

I was under the impression we only had ~100 years worth of oil left, just that its not talked about because climate is more pressing and normal ecconomic pressures will fix the problem if we run out of supply. Is that wrong?

It's likely that we have more than that now thanks to newer methods of oil extraction like fracking. That said, hopefully within my lifetime the primary use of oil will be for plastics rather than power.

I think typically those predictions mean there's ~100 years of oil that's extractable with current prices and technologies, not that there won't be any oil left at all in 100 years.

> And so if we're talking about climate stuff... is nuclear really the only way? Renewables continue to get cheaper and scale up; grid storage with batteries and pumped hydro is already a thing, and plenty of other storage methods are in development, it seems unlikely not a single one of them will turn out to be useful?

Maybe one of them will work out. Do you want to bet the planet on that?

> Plus, carbon capture for fossil fuel electrical generation is possible, just expensive, and not all fossil fuels are equally bad for the climate, so possibly carbon capture + cleaner fossils could be part of the future, too?

Again, maybe.

Yes, there are a bunch of other things that might work out. But fusion is the possibility that's closest to proven. Surely it's worth trying? If it turns out we figure out a storage mechanism that's good enough to make solar viable (say), great. But let's not abandon one of our most promising approaches until we're sure.

To add to your list of currently available proven approaches, would an approach that decarbonized France's energy in just 10 years should also be considered?

It looks like proven track record of decarbonisation if there is one.

You're talking about fission? I think we should push it as far as it will go. At the same time I think there is some legitimacy to the waste and disaster concerns (even if mostly overblown) and so fusion offers enough potential advantages to still be worth pursuing.

I am all for pursuing fusion, for pushing borders of our knowledge.

At the same time, concerns are way overblown about fission. You know, it is regulated to 1/10000 amount of radioactive increase that is known to ever cause harm.

This is causes the designs to be order of magnitude more expensive then they could be. For example, for BWR, fukushima, there is no graphite inside, and reaction is going on only when water is present. There is no reason to have super expensive air-tight building around it.

Moreover, in fukushima case, the fact that it was airtight actually caused it to explode, as hydrogen formed inside it. Should there be ventilation, there would not be chance for it to explode and disperse material further than otherwise.

Secondly, unneeded evacuation actually caused ~1k deaths when they were removing patiends from life support equipment, for example.

As for the waste - it is again purely political problem, you can totally reprocess it, as they do in France and they end up with a few slabs of glass for 30 years of powering Paris. Even if you dont reprocess it first, it takes ridiculously little space, and never harmed anyone.

Compare coal - 14000 tons of coal daily. Just imagine that, and compare this to the fact that it is possible to store _all_ nuclear waste right _on site_, ready for politicians to come to their senses. :)

To look at it this way, most dangerous nuclear plant is the one that does not get built, as it will be for significant part will be replaced with something burining dinosurs.

> To look at it this way, most dangerous nuclear plant is the one that does not get built, as it will be for significant part will be replaced with something burining dinosurs.

Entirely true. But unfortunately there are a lot of nuclear plants not getting built at the moment. Tragic as it is, developing working fusion is probably an easier way to change that than political persuasion.

I guess we can agree to disagree here. What will probably happen is that Russia and China continue to build up nuclear, and export it to whoever will take it.

even the most active proponents of solar/wind will continue to lag way behind in decarbonisation, as the bigger percentage of renuables on the grid the more difficult it is to manage.

at some point optics of the situation will catch up, and political persuasion will happen this way.. in my opinion it will happen much faster than cheap fusion

Methanization is currently expected to be the critical storage component for CO2 neutral energy systems. A major driver of storage need in many places is not renewable fluctuations but seasonal fluctuations: You need more heating in winter/AC in summer. So make Methane and store the gas. Technologically this is all solved.

New opportunities to leak methane and we've seen it's often cheaper to ignore leaks, given the cost of it is incurred by the planet.

If you put the methanation plants next to the gas power plants you don't need leaky gas infrastructure. And methane leaks still seem easier to deal with than nuclear waste.

It seems to me that it’s a question of long term energy needs, i.e. when civilization goes to the next level and wants to send laser-propelled light-sail equipped probes to other planets with 10% speed of light.

Ok, but that's not the question here :) The question is whether the idea that nuclear (and fusion in particular) is the only way to have climate-friendly energy generation and "avert a looming crisis" is outdated, and maybe no longer stands up when today's technology is taken into account :)