RR saying their electricity is "low cost" is marketing fluff. They talk of a "commoditised product", which is a weird way to refer to something they have made zero of. They speak in the present tense, about a future that only exists as fantasy. Nobody has delivered a cost-efficient SMR yet. They seem to envision standalone SMR (instead of, say, putting 5 of them on the same site for scale), which makes the economics worse.

SMRs are a bit of a boondoggle in $$$/kw. They fall into the bad part of the cost curve. The only way we'll get the promised cost efficiencies is after building a bunch of them, and the only way to get there is billions and billions in government subsidies. Even then, I don't think SMRs will ever be cheaper than solar.

I'm not sure where SMRs make sense. There's a lot of work left to do before we'll know the answer to that question. Rolls Royce seems full of it, but the whole game in SMRs right now is telling lies in return for government subsidies. We'll see what truth they can make from that.