“Until the rubber meets the road on an international hydrogen supply chain, a healthy degree of skepticism appears to be warranted.”
Bologna. Not going to indulge the naysayers anymore -- done that long enough. Pedal to the metal and full speed ahead.

I still believe using sunlight to produce formic acid from plastic, transport the formic acid which is liquid under normal condition and use the formic in fuel cells to produce electricity and rehydrogenate the carbon dioxide to make more formic acid is more energy efficient.

I worked in the 'hydrogen future' industry nearly 20 years ago, the challenges are still the same. Regardless of how you make it, hydrogen is impossible to compress without using a LOT of energy. The only practical use for hydrogen, is energy storage in huge tanks at the same p.s.i. as it comes out of whatever type of electrolizer (like the ones that use the process in this article) it's created with. Yet, somehow, nobody has hooked one up to the windmills that are expensive and impracticable.

This is interesting, but existing electrolysis process claim around 80% conversion efficiency to hydrogen, so although a small efficiency improvement, the main saving will be lower cost catalysts. The use of compressed hydrogen in the future keeps coming up, but significant losses in compressing the hydrogen and the cost and safety implications of handling compressed hydrogen are likely to make it unrealistic as a transport fuel. For most applications it may be more realistic to look at renewable fuel distribution via synthetic fuels manufactured from renewable hydrogen or through direct renewable processes.

I would agree that windmills in the ocean could create H2 possibly the cheapest day & night while also storing it plus the Oxygen in tanks below the water. There it may possibly be aided by the deepwater pressure where leaks would also show up quick as bubbles for repair. It then could be piped ashore or loaded onto cargo ships to distant user sites.

Splitting hydrogen should be compared with producing gasoline. How much energy does it take to drill, pull the crude oil from the ground and truck it to the refiner. How much energy does it take for the refiner to separate and refine the gasoline product. The energy required to truck the gasoline to the storage yard, to have trucks filled and to deliver it to the stations. The pumps that get the gas from the underground tank to the consumers fuel tank.

It seems that some people unable to understand the total deal breaker problem w/ ALL hydrogen vehicles!
It is NOT about cheap/easy production or storage of hydrogen!
It is about massive explosive danger of hydrogen gas tanks everywhere!!!
In the real world, there are traffic accidents & leakages & ruptures of gas tanks!
& if those gas tanks are full of hydrogen then the result would NOT be fires; it would be endless massive explosions everywhere in the world!!!

I have wondered what hydrogen does in the upper atmosphere. If you have a billion hydrogen users spill a tiny amount everyday during refills, or little accidents? I've never heard any conjecture on the subject.

Unless someone has repealed the laws of physics, it still takes more energy to create hydrogen through electrolysis than you get back when you use it, either by burning or in a fuel cell. There are also losses due to compression, storage, transport, and decompression. In a few use cases, it might be worth it to deal with all these losses. But for most personal transport (cars and light trucks), you get far better efficiency, with much less mechanical complexity, by just using a battery. Charging times can take longer, but bear in mind that commercial hydrogen fueling stations are expensive, not as quick to fill as gasoline, often unreliable, and very scarce. OTOH electricity is everywhere.

I have worked with hydrogen equipment for 30 years. It is the perfect fuel for the perfect situation. However, it is explosive in air anywhere from 10-90%. It embrittles metals. It can diffuse through containers. IT IS NOT A SUITABLE FUEL FOR VEHICLES. One leak at the wrong time would be far more hazardous than any fossil fuel. Even hydride storage has unacceptable risks. I am even more puzzled by those who want to turn electricity into hydrogen and then back again. There are safer ways to store electricity. What is theoretically possible and what is practical are two very different things.