Re: Decommissioning?
Demand is not fixed in time.
Also, every megawatt of electricity produced from the sun is a megawatt and a half of gas not burnt - it isn't cheap or unlimited and that will steadily bite more under assumptions independent of warming - and CO2 not yet added to the air.
Saving spare solar etc capacity - as it develops - by electrolysis and burning the result in those gas combjned cycle turbines may be worth doing to avoid wasting sunshine or piping gases to homes. Once it is spare, it is cheap.