Regarding the Hydrogen solution, the limitation of an annual consumption is not possible. The challenge lies in the right-sizing of the bottle capacity in order to do a trade-off of storage cost vs dispatch cost (vs electrolizer).

I am not sure I see the problem.  In a system that generates its own hydrogen by electrolysis, sizing the hydrogen tank is relatively complicated task since the optimal size depends on the pattern of production (via electrolysis) and the pattern of consumption (in the fuel cell).  In a system that relies on an external source of hydrogen, the sizing of the hydrogen tank becomes a relatively simple matter depending only on the rate of consumption.

For example, if HOMER reports that the system requires 100 kg of hydrogen per year, then you know that you require 100 kg of storage capacity if you plan to replenish it once per year, or 25 kg of capacity if you plan to replenish it quarterly, and so on.  Seasonal patterns add some complexity, but not much; HOMER's graph of fuel cell output per month would indicate the relative consumption in each month.

The foregoing assumes that the price of the hydrogen in $/kg does not depend on the size of the purchased hydrogen tanks.  If it did, then you might want to do a linked sensitivity analysis on the annual hydrogen fuel consumption limit and the hydrogen fuel cost.  (The Help system contains an explanation of linked sensitivity analyses.)  Then you would look at the sensitivity results to find the sensitivity case that leads to the lowest life cycle cost.