Green hydrogen is made from electricity. The cost of green hydrogen is currently high, but it is dropping faster than pretty much any other energy storage technology. Hydrogen storage is an order of magnitude cheaper (or more) than any other tech. It is expensive because of the cost of electrolyzers/fuel-cells that convert between electricity and H2. These costs are dropping fast at efficiencies of 80%+ along with the cost of solar and wind. If you project the cost declines into the future the economics of producing hydrogen at remote solar wind farms, generating hydrogen, and transporting the H2 by tanker or pipeline are compelling.

Abu Dhabi already sells solar electricity for 1.35 cents/kWh. That price will drop by at 3-5x as solar reaches maturity. Natural gas plants sell power for ~6cents/kWh. Green hydrogen will have at least 5.5cents/kWh ($1.80/kg) of wiggle room to generate returns.

Many people consider batteries to be superior to hydrogen for all business cases. This isn't true for applications that need more than ~10 hours or so of capacity. Sub 10 hours is a huge market and encompasses almost all transportation, but there is a vast market for storage beyond 10 hours.

The Achilles heel of batteries is that the power of the battery and the energy stored by the battery are linked. An Li battery can easily discharge itself in one hour. If you want 10 hours of storage you need to buy a battery that could deliver 10x the power you're asking it to. This dramatically increases the cost and sheer tonnage of materials required to make the required system. Green hydrogen systems only require equipment that can deliver power at 1x the requirement with a storage tank that holds 10 hours of fuel. This means that there is always a crossover point where hydrogen becomes cheaper than batteries. My projection for the future is that this number will be around 10-20 hours.

This makes hydrogen the best choice for many applications and is the reason why lots of governments are into the idea. Transportation is only around ~20% of the energy we use, much of the rest might come from renewable hydrogen in the future.

> Turning electricity into hydrogen and then into motive power for a car is dramatically less efficient than using a battery

This is true —- but the total quantity of battery storage potential is utterly dwarfed by the storage potential for gas, in subsurface storage reservoirs and salt caverns. You can store days worth of energy in batteries; you can store a winter’s worth of energy in gas.

It’s not a matter of efficiency, it’s a matter of quantity. We do not, and will not, for decades, have the kind of battery storage required to support the grid.

> not obviously any better than importing LNG or oil

True, because transporting hydrogen is obviously much worse than transporting LNG or oil. Hydrogen is an impossibly huge pain in the ass, and should be avoided if at all possible, because

Hydrogen

leaks through the smallest gaps.

burns in concentrations ranging from 4 to 74 percent.

burns clear in daylight.

reduces the ductility of metals exposed to it (embrittlement).

has shit energy density to boot.

>This doesn’t make sense to me. Hydrogen is not an energy source

Hydrogen is often compared against batteries. Those aren't an energy source either. I haven't seen anyone seriously propose hydrogen based powerplants. I have seen plenty talk about hydrogen fuel cells as a potential alternative to BEVs and a potential way to get around the multiple short comings of lithium batteries. Fuel cells of course have their own problems. But we've yet to come up with an alternative to gas engines that are as long ranged, quick to fuel, reliable, cost effective, safe and performant while also being net zero or negative carbon.

>So the only way this seems like a win for Japan is if electricity were cheap, battery EVs were not economical, and the loss associated with electrically synthesized hydrogen didn’t matter.

I feel like you are handwaving the issues with BEVs while focusing on the issues with hydrogen. I'm not sure which at the end of the day will turn out to be better. But right now BEVs are incapable of becoming the defacto solution for the simple fact that the battery packs wear out and replacing them will total the car. You can't develop a working used market this way. And lower income individuals simply can never afford to use them. The fact that car markers are going out of their way to design platforms with batteries that are difficult to replace exacerbates the problem. But even if they were easily swapped, their high cost and the fact they are tied to the vehicle means a large chunk of the market can't afford them. And nobody is talking about this.

Japan's plan has been to import hydrogen. Probably from Australia.

Nuclear is unpopular since Fukushima, and Japan doesn't have great renewable resources. The country is extremely land constrained -- and although the "renewables require too much land" argument is silly on the American Great Plains, it does hinder Japan.

Additionally, the solar irradiance is mediocre, and their offshore wind would have to be truly floating wind turbines (which are more expensive) because the continental shelf drops away so quickly.

»Turning electricity into hydrogen and then into motive power for a car is dramatically less efficient than using a battery, and car commutes in Japan are on the short side, so huge batteries wouldn’t be as necessary.«

Which is why Japan is favoring high-temperature hydrolysis here using high-temperature nuclear reactors.

See: https://www.jaea.go.jp/04/o-arai/en/research/research_03.htm...