If you could hypothetically build a fusion plant that would generate several times more power than existing fission reactors at a similar construction cost, you would have so much power you wouldn't have to worry much about transmission losses. At which point you could put it in the middle of nowhere without those constraints and make it actually less expensive for several times more power.
Then for cities power gets cheaper, but for anything that can be built out in the middle of nowhere near the reactor, power gets a lot cheaper.
Unless fusion power is dramatically more efficient than other thermal plants, like 99.9%, your bigger plant will still need massive heat removal structures and systems, which means siting them near water. All the good spots are already taken.
Alternatively you can use truly massive air heat transfer structures, driving up your construction costs again.
I neglected to mention finance costs also. With an untried technology the rate of return demanded is going to be very high, further driving up project costs.
A major cost of the most utilized existing power plants (coal and natural gas) is fuel. If you build a natural gas plant which is twice as big so that you can put it out where the land is cheaper and eat the transmission losses, now you need twice as much natural gas.
Renewables don't need fuel but their construction cost is fully linear, you get no economies of scale. If you want twice as many solar panels then you need twice as much land. If you want to double the size of your fusion reactor, you build an eight story building instead of a four story building on the same piece of land.
> Unless fusion power is dramatically more efficient than other thermal plants, like 99.9%, your bigger plant will still need massive heat removal structures and systems, which means siting them near water. All the good spots are already taken.
An obvious solution is to build them out in the ocean. Then you have plenty of water and you're still not near anything.
And the good spots near population centers are already taken. Some lake a hundred miles from any city won't be.
> I neglected to mention finance costs also. With an untried technology the rate of return demanded is going to be very high, further driving up project costs.
That's only true for the first one. If it's hypothetically ten times more power for the same money, that'll get one built even at a high interest rate. Then once you have it running it's proven technology.
Coal is dead. The competition is PV, and to a lesser extent wind.
> Renewables don't need fuel but their construction cost is fully linear, you get no economies of scale. If you want twice as many solar panels then you need twice as much land.
Yes, and you use odd bits of land close to consumption sites, many of which will have simultaneous use for other purposes. Edit: the linearity is an advantage in that it enables mass production, and gets the benefit of the manufacturing learning curve. So your suggestion of overbuilding on cheap land a long way away from cities applies even more to PV.
> If you want to double the size of your fusion reactor, you build an eight story building instead of a four story building on the same piece of land.
Quadrupling your construction costs. Edit: mainly in the finance cost of the time taken.
Also, making your generators much bigger than current practise increases project risk and therfore cost.
> An obvious solution is to build them out in the ocean.
Quadrupling your construction costs again, and decreasing reliability, capacity factor and productive lifetime. Seawater is nasty stuff.
> And the good spots near population centers are already taken. Some big lake a hundred miles from any city won't be.
It will be used for productive farmland, though. Again, why aren't fission or CCGT plants being built in those places? How is fusion different?
> [High finance cost is] only true for the first one. If it's hypothetically ten times more power for the same money, that'll get one built even at a high interest rate. Then once you have it running it's proven technology.
It's about time to cashflow for utility finance types, and they also tend to want a longer track record than "it worked once". The linearity/modularity of wind and PV is an advantage in the time to cashflow aspect.
Edit: I haven't so far seen anything significant in your replies that doesn't also apply to fission. Utilty project financiers are hard-headed; they'll finance fission if it makes them enough money soon enough.
You are fiddling around the edges rather than demonstrating an order of magnitude cost reduction from PV.
Coal is dying but it's still ~20% of US generation. The natural gas share of US generation has gone up.
> Yes, and you use odd bits of land close to consumption sites, many of which will have simultaneous use for other purposes.
Until you run out of those and then your costs increase worse than linearly because you have to start using more expensive land.
> the linearity is an advantage in that it enables mass production, and gets the benefit of the manufacturing learning curve.
Anything you're going to use for a large fraction of the power grid is going to be mass produced.
> Quadrupling your construction costs.
This is the opposite of how economies of scale work. If you make something bigger, the variable costs scale linearly and the fixed costs stay the same but are amortized over more units.
> Also, making your generators much bigger than current practise increases project risk and therfore cost.
This is no different than needing twice as many turbines to generate twice as much power. It's a variable cost, offset by you getting twice as much power without increasing your fixed costs.
> Quadrupling your construction costs again, and decreasing reliability, capacity factor and productive lifetime.
You keep saying "quadrupling your construction costs" without evidence. We build oil platforms in the ocean on a regular basis. They cost some tens of millions of dollars. Existing fission reactors cost some billions of dollars. The difference from being on the ocean is evidently not the dominant cost. And then you don't have to pay for land.
> Seawater is nasty stuff.
Many existing reactors are situated on coastlines and cooled by seawater. It's not some kind of insurmountable problem.
> It will be used for productive farmland, though.
The price of "productive farmland" compared to the price of land near a city is multiple orders of magnitude less, and high density power generation doesn't need that much land.
> Again, why aren't fission or CCGT plants being built in those places? How is fusion different?
New fission reactors largely aren't being built at all because of regulatory suppression. CCGT plants can't afford to spend fuel generating power which is then lost to long distance transmission.
> It's about time to cashflow for utility finance types, and they also tend to want a longer track record than "it worked once".
If it worked once but is now generating ten times more power per unit of investment capital than any of the alternatives then investors would be lining up, and may not even be needed because the plant operator could use revenues from selling such a large amount of electricity to build more plants with.
Also note the construction timetables: 72 months vs 18 months for PV.
1. EIA 2020, Capital Cost and Performance Estimates for Utility Scale Power Generating Technologies: https://www.eia.gov/analysis/studies/powerplants/capitalcost...
That's not how construction works. Past some small scale, construction cost scales quadratically or worse with size. Building a 100m tall sky scraper is not 10 times as expensive as building a 10m tall 3-story house - it is at least a hundred times more. The only reason why it's sometimes worth it is in ultra-high land-cost areas, such as Manhattan. But you'll never see sky scrapers outside city centers, because construction costs scale horribly with size, even for simple structures. Building a fusion chamber twice the size of ITER would likely be a new 50 to 100 year research project.
> You keep saying "quadrupling your construction costs" without evidence. We build oil platforms in the ocean on a regular basis. They cost some tens of millions of dollars. Existing fission reactors cost some billions of dollars. The difference from being on the ocean is evidently not the dominant cost. And then you don't have to pay for land.
Is anyone building fission reactors, or any kind of huge concrete building out in the ocean at all? Extracting oil from the ocean is many times more expensive than extracting oil on land. I have no idea why you even imagine that it's possible at all to construct a nuclear power plant out in the ocean. There is certainly no precedent for anything even close to that.
First, the power output of a fusion reactor is limited by what the first wall can withstand. Therefore, the power goes as radius^2, where as the cost goes (at least) as radius^3.
Second, the larger a fusion reactor becomes, the more parts it has, and the more reliable each individual part has to be (since there will be no redundancy in many; an leak into the vacuum chamber shuts down the reactor, for example). Reliability is expensive, so each part becomes more expensive as it is required to be more reliable.
Renewables sources are extremely redundant, so they'd scale just fine even with unexceptional per-unit reliability.
Most of your cost difference is that a commercial building isn't just taller than a house, it's also wider. Instead of taking up a third of the lot, it uses the whole thing, and then has 30 times more interior space despite being only 10 times taller. They're also built to commercial building standards which are more expensive to meet.
The costs start getting non-linear when you get into extremely tall buildings that pose special engineering challenges, but nobody is talking about building a fusion reactor into a skyscraper.
> I have no idea why you even imagine that it's possible at all to construct a nuclear power plant out in the ocean. There is certainly no precedent for anything even close to that.
Nuclear submarines survive the ocean just fine.
Yes, they are and it is a huge political issue in nearby countries.
https://en.wikipedia.org/wiki/Russian_floating_nuclear_power...
I don't know how it works in the US, but this is notably not true in the UK and Europe. Gas plants are comparatively small and nestled in, but big coal (to a limited degree) and particularly fission plants are frequently in the middle of nowhere. They're somewhere near a village that can supply a workforce, but siting concerns for nukes were more based on making sure any criticality excitement could be shared with neighbours across whatever nearby border was handy than putting them anywhere near cities.
I don’t know how it costs in US, but in France, fully charging a Model 3 costs about ~5€ at night. That’s not 10x cheaper than gas but that’s a lot cheaper.
https://www.statista.com/statistics/418087/electricity-price...
This doesn't matter, though, because France doesn't need many nukes anymore, therefore doesn't subsidizes new plants anymore. One new plant is built in France, and it already is hellishly expensive: "As of 2020 the project is more than five times over budget and years behind schedule. Various safety problems have been raised, including weakness in the steel used in the reactor." https://en.wikipedia.org/wiki/Flamanville_Nuclear_Power_Plan...
Fission is not cheap if you build a new nuclear plant, not in the Western world. That's why almost no nuclear plants are being build. Making a safe plant is just really, really complicated.
Second, this specific argument can be used to see why fusion is a pipe dream. The primary competitor to fusion is fission. And the fuel costs of fission are pretty low, as you just said. So fusion will not be competitive unless you can built them around the same price as fission plants.
Someone else in this thread talked about S curves. Well, those kind of S curves happen for tech that gets produced in larger quantities, where it is economical to spend engineering resources making the production of the tech cheaper.
But maybe I’m too optimistic :)
But the majority of the reaction energy is carried away by high-speed neutrons, which are pure waste - they can't be captured by magnetic fields, they are heavy and penetrate almost any material, leaving holes behind that make the structure brittle, and when they do get absorbed, they make the atom that absorbed them unstable, turning the material radioactive.
So, at least as long as we use neutri-producing fusion (and any realistic fusion reactor has to) the actually usable energy is not that impressive compared to fission.
Direct conversion is theoretically about 60% thermally efficient, on par with combined cycle gas generators.
This is the non-theoretical part
> that cheaply.
This is the theoretical part. I think a lot of people are misinterpreting my comment. I have absolutely no idea if it can be done that cheaply. But I can say for a fact that the yield of energy is massive. The question is if it can be done cheaply. That's the bet. The question is if you want to take that bet. You have to make similar bets on tons of technologies. It usually takes 10-20 years after something is made till it starts to follow the S curve and become cheap. Even solar and wind followed this.
Fusion power plants still need land, buildings, generators, switchyards, wire, own power consumption, environmental impact reports, planning permits, regulations, inspections, and all the rest. And they need exotic materials and weird engineering in their construction.
Really: how does fusion get us to ~1% (correction: ~5%) of current power prices?
I've never seen a convincing explanation. Usually it's bare assertion. Infrequently it's handwavium/unobtanium.