[jillesvangurp]

Actually storing and transporting hydrogen are technical challenges. It takes up a lot of space and hydrogen molecules are so small they leak through a lot of materials. Not impossible but you need a lot of expensive infrastructure to handle it.

Most hydrogen produced today is consumed very close to where it is produced. Also energy storage and fuel type use cases rank very low on Michael Liebreich's hydrogen ladder. That's a nice tool that ranks different uses of hydrogen by their economic feasibility and overhead. Chemically binding it to something else to store it works of course. Ammonia (NH3) is common for this; and in fact the biggest use case for hydrogen. People have speculated about using that as a fuel. It's much easier to store and transport. And of course these chemical transformations also have an energy cost.

[pfdietz]

Actually, storage and transportation are positives for hydrogen. It's easier to transport and store hydrogen than it is to transport and store electricity. Hydrogen can be stored underground in caverns very cheaply (this is a demonstrated technology already in use for buffering hydrogen produced from fossil fuels), compared to the cost of equipment for storing electrical energy. Hydrogen is a viable for seasonal storage of renewable energy, unlike batteries.

The negative for hydrogen is poor round trip efficiency of electricity -> hydrogen -> electricity. But for sufficiently long storage times the lower cost of storage capacity vs. batteries overwhelms that, and hydrogen becomes cheaper for grid storage.