I'd definitely have to look into the actual chemistry of the process, but I don't find that claim terribly outlandish on principle. Most combustion plants end u

I'd definitely have to look into the actual chemistry of the process, but I don't find that claim terribly outlandish on principle. Most combustion plants end up having decent efficiency (as you mentioned) because of their access to heavy stationary insulation materials and co-generation/waste heat reclamation, but one way or another, they still end up running into the Carnot efficiency limit for heat engines. Since fuel cells operate electrochemically, they don't have that same limit, which means their theoretical efficiencies are often higher (and the ability to get somewhat near those efficiencies track as well). I'm not sure if they're comparing to full-size plants or not, but the differences between the two tend to be more pronounced as size and weight of generator decrease, since heavy insulation and waste re-use are more difficult, but fuel cells stay (somewhat) the same. I certainly agree with your observation about methane being an interesting path forward for storage technology for excess renewables, though.