[zdragnar]

I think the argument is that cheaper renewables are only cheaper because they externalize the cost of storage to either expensive batteries or tech that doesn't exist yet.

Nuclear, otoh, provides constant output (barring maintenance windows) and has the full cost of the plant, from construction to decommissioning, built into it.

We've got nuclear submarines that run just fine- the prototypal tiny reactor. Had we built more and smaller nuclear power plants decades ago, we could have averted a lot of emissions and so on and so forth.

[pjc50]

I've heard that argument a lot but .. that's not how the electricity market is actually structured, at least in the UK.

Both wind farms and nuclear power plants end up with a "strike price", which is effectively a collar option around the spot price so that revenue is guaranteed. It can in some cases result in wind farms having to pay money back if the spot price goes up too much.

Separately there is the capacity auction https://www.emrsettlement.co.uk/schemes/capacity-market/ and a fast frequency response market (which batteries are starting to appear in).

> Had we built more and smaller nuclear power plants decades ago

The "learning rate" for reactors appears to be negative: over time, they get harder to build. Possibly as people discover more ways in which things could go wrong. Hinckley Point C is over time and budget.

[ZeroGravitas]

We build bigger nuclear reactors because they are cheaper than small ones. Similar to big wind turbines, there's fundamental physical properties of scale that make the electricity from big nuclear plants cheaper.

Small nuclear plants are (maybe) cheaper per "plant" but not cheaper per watt and likely never will be.

[adrianN]

Which part of gas turbines and electrolysis doesn’t exist yet?

[ballooney]

The electrical efficiency of breaking water to hydrogen, then combusting hydrogen through a turbine to generate electricity, compares extremely disfavourably to most other forms of storage - it takes about 50kWh of electricity to produce 1kg of Hydrogen, and if you propagate that back through a turbine and make some conservative assumptions about electrolyser costs and so on and so on, you're sort of approaching 5x the cost of others forms of renewable electricity to make electricity from stored hydrogen.

Of course, if we're building enough renewable capacity that electricity is basically free when it's sunny or windy, that changes the eceonomics and maybe we should all be making hydrogen in that sort of [bumpily]-abundant future.

However, storing hydrogen is also a pain - the density is crap even as a liquid and very technically challenging, and the density is mind-bogglingly crap as a gas - you'd want to find some vast geological underground reservoir in which to store it economically.

None of these are insurmountable, it's just not an especially attractive option as things stand.

[adrianN]

Total system cost is what matters, efficiency is only a small part of the equation. As far as I know a mixture of batteries and hydrogen in a renewable grid looks like the cheapest solution.

Storing hydrogen is trivially done in salt caverns. We already do it that way today.

[pjc50]

Don't worry, the NIMBYs will come for that just as well as nuclear. https://news.stv.tv/north/plan-for-uks-biggest-hydrogen-plan...