[standeven]

I've worked with hydrogen (H2) quite a bit recently. Embrittlement and leakage are easy to work around, but here are the pain points I've seen:

1. H2 is still expensive. Most fuel cells require very pure H2 (five nines; 99.999%), or else it can damage the internal membrane. This pure H2 is not very affordable outside of a limited number of fuelling stations.

2. The rules around H2 use and transportation are still fuzzy. Despite being around for so long, regulations are still lacking or unclear.

3. H2 is light weight but takes up a lot of volume, limiting the usefulness of small-scale applications. Compressing it to liquid takes a lot of energy.

4. Fire/explosion risks, as you mentioned.

5. Fuel cells are expensive. If you look at financial statements for most fuel cell companies, they are selling them at a loss, meaning most fuel cells sold today are subsidized by government grants and investors.

6. The oil/gas industry is still pushing "grey" and "blue" hydrogen, which uses natural gas and emits carbon to produce H2.

I think H2 will play an important role, especially in decarbonizing steel making and large transportation applications, but people need to be aware of the limitations and longer timelines required for widespread adoption of green H2.

[ViewTrick1002]

I love the hydrogen ladder to visualize this concept. To decarbonize fertilizer hydrogen is unavoidable, for personal transports it has been uncompetitive the past decade.

https://www.linkedin.com/pulse/clean-hydrogen-ladder-v40-mic...

[dragontamer]

> 3. H2 is light weight but takes up a lot of volume, limiting the usefulness of small-scale applications. Compressing it to liquid takes a lot of energy.

My understanding is that H2 is seeming to standardize upon 300-bar (aka: 4500ish PSI).

There's liquid and a few other more difficult storage (700-bar / 10,000 PSI for example). But 300-bar is where a lot H2 stuff is standardizing today.

Its not quite as dense as in liquid form, but it starts to be usable at 300-bar. Of course, the thicker and heavier steel needed to hold H2 at this pressure makes it unsuitable for say... drones. But its more than usable for H2 Forklifts and other smaller vehicles.