The problems begin with its production. Hydrogen doesn’t exist on Earth in its pure form. It needs to be produced, using electricity. Today, roughly 95% of hydrogen is produced using fossil fuels in an emissions-intensive process, with each kilogram of hydrogen resulting in 10 kilograms of carbon being emitted. There is a great deal of interest in producing it using sustainable electricity, but the requirement for intensive energy to produce pure hydrogen remains – and there are two additional problems – storing and transporting it.
Pure hydrogen is highly volatile and must be stored safely, but storing it is challenging. As a gas, it requires cryogenic storage and extreme pressure storage vessels to keep the hydrogen intact. As a liquid, it boils off at normal temperatures. For example, a hypothetical car with full liquid hydrogen tanks sitting in your garage on Friday, would have empty tanks on Monday morning because of normal temperature boil off.
Transporting hydrogen, which is highly volatile, is equally challenging. Because it is the smallest molecule, hydrogen works its way between the crystalline structure of metals, making them brittle, resulting in cracking and failure. There is no distribution infrastructure in place now that could handle hydrogen. We can imagine it, but in actuality, the hydrogen economy is many years away and may never be practical.