technology

Untrained people handling hydrogen just sounds like a bad idea. And for most part the talk about hydrogen as fuel is just to keep combustion motors around for longer.

But yeah the hydrogen tech for vehicles very much feels like they just don’t like the idea of people plugging their cars in at home instead of going to their lil fill-up stations where they can get a cut of the pie.

Definitely. Basically all commercial hydrogen comes from a process called methane steam reforming (so-called "grey hydrogen"). You take high-temperature steam and use it to crack natural gas (mostly methane) into carbon and hydrogen, usually heated by way of just burning the natural gas since you already have a supply of it. A big problem is that the oxygen from the water and the carbon from the methane likes to get together into CO2, which is just vented into the atmosphere. Fossil fuel companies are deeply involved in hydrogen production and spewing out the most famous greenhouse gas as a side effect.

Sometimes they make a show of trying to capture the CO2. The marketing calls the hydrogen recovered this way "blue hydrogen", but it's very uncommon. "Green hydrogen" is from electrolysis which has no CO2 emissions, but nobody uses that industrially, it's just a PR gimmick to try to convince people that all hydrogen is clean. The power requirements are absolutely ridiculous for the amount of fuel you get from it.

Ironically, one of the few truly green portable fuels is synthetic methane using something called the Sabatier process. The short version is that you combine electricity, water, and CO2 over a catalyst. The output is oxygen and methane. If the CO2 comes from the atmosphere it's carbon-neutral. This is what most practical Mars exploration missions are planned to do. Mars is still close enough to the Sun for solar power to be practical. Combine solar power with subsurface ice (which is proven to be everywhere on Mars) and Mars' almost-entirely-CO2 atmosphere, and you can manufacture as much methane and oxygen as you want. The stored methane and oxygen could also work to power methane fuel cells in case of dust storms that would block solar power, and of course the oxygen would also be used for breathing.

NASA's Perseverance rover actually has an experiment on board, a small-scale Sabatier machine tech demo that worked perfectly. Human Mars exploration has a whole heap of technical challenges left to be solved but at least manufacturing fuel and oxygen isn't one of them.