content: It's about energy storage and energy density, and how much it costs to optimize those things. The article says they're planning to use solar energy to generate the hydrogen. Solar energy is abundant and as far as I know, hydrogen cells lose their stored energy way slower than conventional storage methods like batteries, capacitors, etc. This means the abundant solar energy can be stored with much less loss for use later. That's the real end goal, I think: solar energy is abundant and "never"ending.... But intermittent. Day/night cycle, weather, etc. Plus, even when it's around, the output is constant. To truly leverage solar as humanity's future energy supply, we need to be able to call on it on OUR schedule, and increase available output as demand fluctuates. Good energy storage solves these for solar. See also, Elon Musk's Tesla Powerwall.