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Comment by Gwypaas | Hacker News Reader

The fusion question simply boils down to:

How are you going to generate power with your fusion plant? Steam?

Coal and nuclear are uncompetitive simply from the cost of the steam side. Today you can just about give a steam plant free energy and it still makes a loss.

Solar or wind does not have this limitation. CCGT gas plants gets around it by having a turbine giving raw mechanical power and then utilizing the same awful steam side to get the last percentage points of efficiency at a much smaller required scale. Unless you can step around the steam turbine I am not so positive on fusions future outside of incredibly small niches.

Coal still gets built where gas infrastructure does not exist, but that's about it.

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We should have seriously invested in next generation turbines for high temperature systems.

A efficient small CO2 turbine powered by a small GenIV nuclear reactor would be absolutely incredible, in terms of economics, reliability, environment, efficiency, energy security and so on.

But sadly, neither high temperature reactors nor turbines have received the funding they should have over the last 50 years.

Even with a CCGT a high temperature nuclear plant could be really competitive specially if you want to have power when both wind and solar are at 5% utilization.

Helion and similar methods side-step the issue by using (mostly) aneutronic fusion.

https://www.youtube.com/watch?v=_bDXXWQxK38

https://en.wikipedia.org/wiki/Aneutronic_fusion

Also, discussing solar and wind without discussing the base load/storage problem skews the discussion towards solar/wind. Steam plants don’t face those challenges in the way those two do; storage is as much a challenge for solar as steam is for nuclear.

I would expand on your statement by saying that Helion is planning to generate electricity by directly extracting the kinetic energy of the particles created in the fusion reaction. And they need charged particles rather than neutrons.

(I watched the video and really it's as simple as charged particles moving in and creating a magnetic field inside loops of metal which in turn generates a current that can be used. (Just add several dozen years worth of post-doc maths to sort out the details)

Steam plants are ripe for a thermal battery that can take in excess electrical production and store it to fire up turbines on demand. It's an entirely different class of battery on the range of energy storage separate from direct electrical grid batteries. One example, the reversible rust batteries:

https://clearpath.org/our-take/a-reversible-rust-battery-tha...

Is this true when making an apples to apples comparison. That is to say: are wind and solar cheaper when having enough energy storage for intermittent supply on the daily, weekly, and yearly cycles?

Also, is the true cost of land being factored? The vast majority of "empty" land in the US is actively used for farming.

What you are looking for is "levelized cost of energy". And, yes, renewables are cheaper even when you count in storage or gas turbine backup. As storage gets built out, the gas turbines will be fired up less frequently.

Land is utterly a non-issue. Not only is there plenty of spare land, solar and wind can be sited on dual-use pasture and cropland, as well as floated on reservoirs.

I'm not talking about LCOE with a fossil fuel backup. I'm talking technologies that actually decarbonize the grid.

If land is not an issue then I challenge you to sequester 156,000 square miles (~1.7% of the total land in the US). This is a relatively optimistic estimate with no overhead given for overproduction or growth. This goes without speaking of the carbon footprint of the carbonized industry necessary to grow solar production by 50x.

https://www.nrel.gov/docs/fy13osti/56290.pdf

https://www.eia.gov/energyexplained/us-energy-facts/

More dogmatic thinking. "If it's not perfect for my Alaskan hut north of the Arctic circle then......"

If you care about land use and is not using it to simply sow discontent mandate solar above parking. The US is a complete wasteland when you consider land use. Or simply build it together with agricultural use. Wind is perfect for that, solar may lower some crops output while increasing others.

https://www.strongtowns.org/journal/2019/11/27/parking-domin...?

Next, start eating vegetarian.

https://ourworldindata.org/grapher/land-use-kcal-poore

> This goes without speaking of the carbon footprint of the carbonized industry necessary to grow solar production by 50x.

Great that we're aiming to decarbonize the industry.

If we're talking about OP's claim that "fusion will never happen," then OP is wrong if fusion is outcompeted by renewables in southern California but viable in Canada.

Great that it's windier closer to the poles and windier during the winter.

Unless you're talking about north of the arctic circle, then sure. You can fill that niche of a couple of hundred thousand people living in the global north and not within striking distance of massive hydro reserves.

https://globalwindatlas.info/en

Or like this study a while back finding building SMRs in the Canadian north close to a laughable proposition given the power requirements, costs and tiny niche market.

https://www.sciencedirect.com/science/article/abs/pii/S03014...

Fusion would be trying to compete with imported fuel, just as fission fails to achieve today except where massively subsidized. In the nearish future, that fuel will be synthetic, likely ammonia, produced at solar farms in the tropics, or at wind farms nearer by.

Of course in places where transmission lines are practical, power will be imported that way instead.

No one will ever be able to maintain a cartel on the synthetic fuel supply.

I have already addressed these topics in the message you replied to. Which see.

Interestingly, China has been steadily improving in steam. US coal plants average around 33% efficiency, and the latest coal plants in China are close to 50%. The way electricity price controls work in China if a plant isn’t at 300g per kWh or better, the more you generate the more you lose.

Coal is fine with steam. Make it supercritical and do fancy stuff. You're simply piping water through furnace with extra steps. It is a material science questions.

For all traditional water reactors you are using the water to slow down the neutrons. Enter the Pressurized Water Reactor(PWR). Now the entire reactor is pressurized with all the complications that bring and through Carnot's Theorem you gain some efficiency.

This is nuclear's problem with trying to become more efficient.

isn't this just that China has newer plants than the US? in the US, no one is building new coal plants (for good reasons)

Also, I suppose another problem with steam is that you're heating up the planet directly. Perhaps someone with active thermodynamics knowledge can say how much of a deal that is.

We also get direct heating when we burn fossil fuels, but that's a tiny percentage of their greenhouse impact.

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