Hydrogen is not a source of energy, it is a carrier. You have to create hydrogen gas from water (or as is done today, from fossil gas). This takes energy. This

Hydrogen is not a source of energy, it is a carrier. You have to create hydrogen gas from water (or as is done today, from fossil gas). This takes energy. This energy can just as well be used to power the thing directly. Which is significantly more efficient. https://pbs.twimg.com/media/D0MuwO9V4AEGbUo.jpg https://pbs.twimg.com/media/D0MuwO9V4AEGbUo.jpg Hydrogen is brought up as a potential storage method which may work, but it makes metals it touches brittle. It is not like storing fossil gas. There are ways to limit it, but it has costs. https://en.wikipedia.org/wiki/Hydrogen_embrittlement https://en.wikipedia.org/wiki/Hydrogen_embrittlement Hydrogen in cars also uses expensive metals, platinum in the fuel cell. https://www.sciencedirect.com/science/article/abs/pii/S0360319921037022 https://www.sciencedirect.com/science/article/abs/pii/S03603...