Electricity is way cheaper at the poont of generation than for residential consumer. IIRC, solar now gets to about 3$ per Mwth, so purely energy cost would be

Electricity is way cheaper at the poont of generation than for residential consumer. IIRC, solar now gets to about 3$ per Mwth, so purely energy cost would be about 0.33$ per kg of propane if 100Mj of input energy per kg of propane stands for that electrolyser plus stated 13Mj for Co2 capture for 1 kg of propane. So, the cost is not negligible, but could be competetive even now, and solar is likely to get cheaper.