Where you want electricity for static applications, I would suggest that overall system efficiency is likely to be better with PV/advanced batteries than with PV/Hydrogen from either route. Costs are reducing, and there is a strong likelihood that future advanced batteries (high cycle efficiency, robust, last for decades) will use low cost readily available metals such as lead, sodium and zinc rather than lithium or other more expensive materials.

One thing in favor of the direct hydrogen conversion is that potentially the system will in effect be water cooled – avoiding the high temperature penalty currently paid by conventional PV.