My question about fusion isn't about thermodynamic efficiency, but about economics. Our waste heat solutions produced electricity at about 2x the LCOE of a natural gas turbine. Since it was carbon-free electricity, by selling the carbon credits we could get close to the ROI of a natural gas plant. A NG plant might have a 20 year IRR of 14-16% - we could get to 11 or 12. But that was enough to kill the project.

And we have other technologies that produce carbon free electricity at a price close but not quite at NG turbines - renewables + storage, for example, or geothermal. But those aren't considered economic to build right now, despite being here and ready and understood.

I might be wrong, but I can't imagine a nuclear fusion plant getting within spitting distance of a NG plant for capital cost. And if it's even twice as much money -- which seems wildly optimistic -- maybe nobody will build them. Or maybe they will, because there are other factors at play besides carbon free electricity and cost! That's what I'm asking - what are those other factors?