One question leaps to my mind after reading this.
Why convert electrical energy from solar into hydrogen. Why not just use the electrical energy directly?
The only way that I can see hydrogen being a part of the future is if solar has supply limits. We talk as if we can infinitely build solar panels. This may not be the case.
It is still very uncertain what the supply of rare earth minerals that are necessary for solar looks like. We could find out that we burned through the worlds supply without getting anywhere close to our goals.
In that scenario I can see using the available solar capacity to generate hydrogen. Then building an energy framework on the hydrogen.
Otherwise, why bother.