The paper also assumes we'll make have feasible CO2 energy capture and hydrogen electrolysis and storage. It required time, effort, capital, and and multiple engineering breakthroughs. If your plan is contingent on technologies that aren't available... it's just a long winded way of saying you don't have a plan.

Actually, we just need improvements in fusion power and then we don't need solar, wind, or battery storage!

The paper assumes CO2 energy capture at $200/ton. That's "scale up existing technologies" pricing, not "engineering breakthrough" pricing.

It also assumes a vast hydrogen electric grid storage network - this is only theoretical, nobody has actually deployed a facility that converts electricity to hydrogen, and back to electricity. At best this is, "scale up heretofore unproven technologies", not "existing technologies".

In the same sense that commercial breeder reactors are theoretical (which is conservative, as you can't actually buy a breeder reactor). But nuclear advocates don't talk about those much, even though they'd be needed for a nuclear powered world.

But we don't need commerical breeder reactors. The USA just needs to build 4 PWRs for each reactor it presently has to generate electricity entirely from hydro and nuclear. This is vastly more feasible than provisioning terawatt hours of energy storage.

"Just scale up" is a good summary of how to decarbonize through nuclear power. We have decades of experience building nuclear plants. Not so with hydrogen based electricity storage. Plans for renewable grids call for the use of novel electricity storage systems because none of the existing storage mechanisms are feasible. Until we've built the storage mechanisms proposed, any plan involving it's use is effectively hand-waving a big part of its implementation.

Powering the world (all energy, not just the grid, and not just the grid in the US) with PWRs won't work, because we run out of cheap uranium too quickly. Breeding is needed for sustainable use of nuclear.

Incorrect, we have plenty of uranium both terrestrially and through seawater extraction: https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

Sure seawater extraction is more expensive. But procuring raw uranium is a tiny fraction of nuclear's cost. You'll see statistics saying nuclear fuel is a significant cost, but most of that expense is from enrichment not extracting raw uranium.

Seawater extraction is even less plausible than breeders. The polyamidoxime fibers that article discusses do not have sufficiently long service lives. Also, if the uranium were to be burned in PWRs, the effective power per ocean area of uranium collectors would be much less than the effective power/area from photovoltaics.

Uranium is a small fraction of nuclear's cost at current uranium prices. But eventually that runs out, and the price of uranium would increase dramatically. This has always been the motivation for breeders.

Again, the energy density of uranium is such that even if seawater extraction remains expensive, it has negligible impact on nuclear power costs: https://en.m.wikipedia.org/wiki/Economics_of_nuclear_power_p...

> The cost of raw uranium contributes about $0.0015/kWh

Even if this increases by an order of magnitude, this is not significantly impacting the cost of nuclear power. Heck, even two orders of magnitude still amounts to ~1% increase in net cost per KWh.

RE your edit after I commented:

> Uranium is a small fraction of nuclear's cost at current uranium prices. But eventually that runs out, and the price of uranium would increase dramatically. This has always been the motivation for breeders.

Again, the cost of raw uranium extraction amounts to $0.0015/kWh in nuclear generation. A 100x cost increase will not amount to even a quarter of a cent per KWh. This is the power of fissile energy density: it's so energy dense that the cost of extraction is largely decoupled from the net cost of nuclear power.

By comparison, how would the price of lithium ion batteries be affected if the price of lithium carbonate increases by 100x? Half of a battery's cost comes from the cost of cathode material: https://www.visualcapitalist.com/breaking-down-the-cost-of-a...

If $0.0015/kWh is the current fuel cost, a 100x increase would bring it up to $0.15/kWh. That's 15 cents per kilowatt hour, not a fraction of a cent. It would make nuclear power among the most expensive of electricity sources from fuel cost alone.

If lithium increased in price by 100x, we'd switch over to one of the many other options for energy storage. If uranium increases in price by 100x, burner reactors are screwed (well, even more screwed than they already are.)

"many other options" like what? You can't just say we'd use alternatives and then neglect to specify what those alternatives are. All storage options available to us fall short. Hydropower is geographically limited. Batteries are in too short supply, and are mostly being directed to other applications. Plans for a mostly intermittent grid invariably call for hydrogen, compressed air, giant flywheels, or something else to solve the storage problem. We have no practical experience building electric storage with these systems, so it's effectively a giant hand-wave.

A plan that's dependent on something like hydrogen electric storage is like a plan calling for widespread deep-drilled geothermal power: We have plenty of experience with drilling, and steam turbines. Iceland has plenty of geothermal power - but it sits right on a fault line. That's no guarantee we'll actually be able to build geographically-independent geothermal power. Would you view a plan that involves widespread installation of geothermal power as feasible?

There are many chemistries for batteries. We're even seeing some of them pushed to commercialization. Chemistries based on common elements like sodium or iron would evade concerns about material availability.

There are thermal storage technologies. An example is pumped thermal storage. This involves (1) adiabatically compressing argon, (2) transferring heat from the compressed argon to a hot store (say, molten "solar salt", a potassium/sodium nitrate salt mix) by a countercurrent heat exchanger, (3) expanding the cooled argon back to the initial pressure, (4) using that now cold argon to extract heat from a "cold store", say liquid hexane, cooling it to -100 C. To discharge, reverse this process. Round trip efficiencies similar to pumped hydro could be achieved. The high temperature side of this process is within the creep range of ordinary steel, so no exotic materials are required.

Resistively heated thermal stores would not be quite as efficient (maybe in the low 50s%) and involve higher temperature (~1200 C), but could work with existing gas turbines. Babcock and Wilcox are commercializing this now, using their very nifty direct contact sand/gas fluidized bed heat exchanger. The storage medium here would be ordinary sand, of which there is an unlimited supply.

This last approach also allows an external heat source, such as hydrogen combustion, to act as a backup heat source. So if your thermal stores run out, you can keep running them by burning hydrogen (or some other e-fuel). The marginal capital cost of this capability would be very low, just that of adding a fluidized bed hydrogen combustor to heat the sand.

Thermal storage has only been used for district heating. There is no commercial electric thermal storage project in existence. Babcock and Wilcox have not broken ground on a prototype thermal electric storage plant, let alone a commercial one. They signed an intellectual property agreement [1], this is not even remotely the same thing as commercialization.

Hydrogen electric storage has issues producing hydrogen without emitting fossil fuels: almost all hydrogen produced today is through steam reformation which emits carbon dioxide. Electrolysis has issues with corroding electrodes, in particular. We've known about electrolysis for decades (centuries?) but its disadvantages have not been solved. Likewise, how long have sodium and iron batteries been on the verge of commercialization? How long did lithium ion batteries take to reach the scale sufficient for EVs? Sources say that they're projection sodium ion batteries to be produced at 20 GWh per year by 2030 [2]. Even if that level of optimism pans out, this is nowhere near a scale sufficient for grid storage.

People still hope for lithium ion batteries to deliver, because it's the best (or least-bad) option and none of the competitors are set to unseat it. And remember, almost all of this battery production is going to EVs and electronics, only a fraction of it is going to grid storage.

1. https://www.babcock.com/home/about/corporate/news/babcock-wi...

2. https://cen.acs.org/business/inorganic-chemicals/Sodium-come...