I was trying to create a transformation module for Hydrogen plant based on electrolyzation technology. Although it is obvious that the water is the feedstock (but not the fuel itself, yet chemically it is) and electricity is the auxiliary fuel. But since LEAP requires feedstock fuel, i don't think Hydro would be the feedstock fuel.
Additionally, i have tried a few approached but could not get the hydrogen plant capacity being calculated. It ultimately goes to import.

Parameters I have used for hydrogen plant are process efficiency, maximum availability, capital cost, endogenous capacity, dispatchable.

So, in summary

If the process is electrolysis then I think the feedstock would be electricity. Of course, hydrogen can also be made by reforming natural gas or methane in a different process.

Charlie