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Comment by alex_young | Hacker News Reader

I really don’t understand the attraction of hydrogen as a fuel source.

Currently it’s a byproduct of fossil fuels, and while you can produce it via electrolysis, it doesn’t seem like a super high efficiency conversion chain if you already have electricity.

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The attraction of hydrogen is precisely that, as a fuel source, specifically because it's produced by fossil fuel companies cracking fossil fuels, and it lets them largely maintain their business models. It was also pushed heavily by car manufacturers as a stall to get around clean air mandates while avoiding developing electric vehicles (with their inherent threats to after-sales service revenues). Now individual, corporate and national egos are on the line and sunk costs are so huge that many players are politically incapable of backing out.

As an energy storage medium it's terrible. It's inefficient to produce, relatively inefficient to use, very difficult to store, and inconvenient to transport. There's no reason to prefer it over lithium batteries except that it perpetuates the refinery -> distributor -> truck -> fuel station-> consumer model.

Our climate is on the ropes -- if 'blue' hydrogen (ie, fossil hydrogen with carbon capture) is a convenient stopgap, I say we go for it. Sure, it's not renewable, but it also would be carbon-neutral (assuming the carbon is 100% captured). We shouldn't let ideological issues get in the way. So what if fossil fuel companies benefit from it instead of battery companies?

If we were to implement a carbon tax instead of picking winners, 'blue' hydrogen would come out ahead of 'green' hydrogen for at least the next decade, but hydrogen fuel cell vehicles would probably still loose out to batteries for most automotive applications.

If there were nothing else on the horizon it'd be better than nothing, for sure. And a cap-and-trade carbon tax would work wonders especially if the proceeds were used for market stimulus or something. It's just that we now have practical battery tech so we can jump straight to a battery storage + distributed solar infrastructure for everything and skip wasting an incredible amount of resources rebuilding a giant chunk of our existing infrastructure for only marginal gain.

If the only purpose of the H2 economy, from the perspective of its investors, is to greenwash the fossil fuel industry, then that explains the apparent lack of interest around photocatalytic H2 production. I expected a direct solar hydrogen production industry to start taking off years ago, but lately, from what I can see, it seems to have just languished in obscurity.

Here's an open-access study from 2014 on various metal oxide nanoparticle catalysts for a solar hydrogen evolution reaction:

https://link.springer.com/article/10.1007/s10562-014-1397-z

And a more recent one where TiO2, one of the cheapest safest nanoparticles, is used as the catalyst:

https://www.sciencedirect.com/science/article/pii/S187853521...

Indeed. You'd have to legislate that hydrogen for vehicles could not be produced by steam reforming and add lots of regulation around tracking the origin of all hydrogen that reaches the vehicle. Otherwise people will just use the cheapest source of hydrogen, and presuming the demand for other fossil fuels is going down at the same time, that's going to be exclusively very cheap methane feed stock.

Or we could just tax carbon. sigh

Hydrogen is very cheap to store. Renewable electricity is free once the panels/turbines are built. There will be long periods with zero price energy and other times with limited energy. Making hydrogen to use for the energy into the dark/unwindy weeks may make more sense than more excess solar/wind.

Batteries are not well suited for medium and heavy duty trucking (or trains or long distance marine) because the weight of the batteries is too great. These are areas where hydrogen can be better than batteries.

Specifically rail lines are candidates for electrification, and batteries need only be large enough to cover non-electrified sections and outages. In terms of overall freight movement, more can certainly go over electrified rail. Last mile bulk delivery by road (truck), whether BEV or biodiesel ICE would still represent an overall significantly lower carbon footprint. The FCEV hydrogen lobby mistakenly assumes long-distance trucking is a non-disruptable and necessary part of freight delivery.

Rail line electrification is really expensive. For rarely used lines it makes little economic sense.

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