Tom Anderson wrote:

Ultimately, it all comes down to where you're going to get the energy
from; hydrogen is a fundamentally synthetic fuel, so you need to supply
electricity, hydrocarbons or light (if you're a photosynthesist) to make
it [1]. IMHO, the only practical carbon-neutral approach would be to use
nuclear electricity; i doubt that photosynthesis or renewable power plants
would be able to supply enough power.

They probably would, but only at certain times. The nice thing about
using electricity to produce hydrogen is that you can do it at the time
the electricity's cheapest. One of the main criticisms of wind power is
that it usually produces electricity at the wrong time. Hydrogen
generation when there's a surplus could be part of the answer.