[adorno]

The two most common methods for producing hydrogen are steam-methane reforming and electrolysis (splitting water with electricity.

My question is really about energy.

It requires energy to get the fusion going. It requires energy to produce the hydrogen that would be used in the fusion.

Thus, we have energy expended in the production of the hydrogen and more energy to get the fusion 'sparked'.

So, what would be the net gain in energy from the fusion, after the production of the hydrogen and the fusion of that hydrogen?

[TexasGator]

"after the production of the hydrogen"

Negligible amount. E=MC²

Much less mass is converted in the chemical reaction.