>people start talking about supercritical co2 turbines
>supposedly they can be much, much smaller than existing steam turbines

The first problem is they run at over 700ºC, way past what is enough to soften aluminum, so they need to use some sort of stainless steel alloy, which tends to be crazy expensive to machine, but...

How the hell do they seal the bearings so that the supercritical CO2 won't leak through the bearings that hold the gearbox/generator coupling? I can't think of a single material that would work.

Is this going to be... vaporware?