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Comment by alex_young | Hacker News Reader

"Thanks to the local process of obtaining hydrogen, using only excess wind power, this will be the first European ferry powered entirely by renewable energy. Both the production process for hydrogen and its use as fuel don’t emit any toxic by-products."

Intriguing, since hydrogen production is almost universally a byproduct of fossil fuel production. Not a ton of information here...

I did a little digging, and indeed this project is using electrolysis powered by wind / tidal energy projects on a small Scottish archipelago named Orkney. They produce 130% of the power they consume, so they turn the remainder into H. Smart.

Here's a really interesting article with lots of details: https://www.bbc.com/future/article/20190327-the-tiny-islands...

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Hydrogen seems like a really interesting potential solution to the renewable storage problem. I've done a bit of research in the past and seen that there are some early stage projects investigating this, but I'd be curious to hear from anyone who might know more.

It’s not really that advantageous for energy storage. The round trip energy efficiency is less than 50% so half of any stored energy is wasted.

Perhaps surprisingly, the round-trip efficiency of an energy storage medium becomes relatively unimportant when the top-line cost of production gets low enough. Other costs come to dominate.

The odds-on favorite for utility-scale battery storage is iron-air batteries. Nobody even mentions the round-trip efficiency of those, so it must be pretty awful. But they are darned cheap. We can expect solar, in particular, to be routinely massively over-provisioned, so that much of the time most of the output would otherwise be wasted if not used opportunistically to charge batteries or hydrolyze water to synthesize H2 or NH3.

Iron-air batteries are literally just fuel cells that involve iron instead of hydrogen. THe odds on favorite is hydrogen fuel cells and it probably can’t be anything else (short of some kind of nuclear solution).

You keep saying so, but what I am seeing is serious plans for iron, and synthesizing NH3 as portable fuel, but very little activity on H2. Is there actually any current work on industrial-scale H2 synthesis for storage, as opposed to for use in e.g. steel production or fuel?

It should be noted that using hydrogen for steel or fuel production lead almost directly leads to some kind of hydrogen storage. If you can make that much hydrogen, it just becomes a natural step to use it as a energy storage system.

Also, the scale of hydrogen storage facilities far exceeds anything else ever proposed: https://www.pv-magazine-australia.com/2021/10/23/weekend-rea...

It's clear that obsessing over the last step is unnecessary. As soon as you have the hydrogen available, there will be many obvious solutions available.

I don't doubt that, once hydrogen becomes heavily used as a fuel--exclusively for aviation, I expect--it will then also become useful, secondarily, as a storage medium for utility power. But the first condition is barely even in planning stages, if there. By the time hydrogen as bulk fuel does happen, other storage for utility power will be very mature, and hydrogen will need really compelling advantages to be able to compete in places where it is not already being stored as aviation fuel.

The cited article points out that utility-grade storage in salt caverns is still a wholly hypothetical possibility, and speculates on problems that might yet render it impractical.

It's advantage is that fact that it stores multiple orders of magnitude more energy than anything else, at a cost level that is orders of magnitude cheaper too. It's a matter of when, not if, hydrogen becomes the primary energy storage mechanism.

Storing hydrogen underground has existed for decades. It's already been accepted by people in the industry that this is a solved problem.

Yet, the article you cited yourself says the opposite: that it needs study to determine its practicality.

I don't doubt that whatever problems turn up will be solved, in time. Underground storage of liquified hydrogen, rather than gas under high pressure, seems like a great idea, since earth is such a good insulator, but they don't seem to be talking much about LH2.

The methods used to oxidize H2 seem to produce a great amount of waste heat. If you have uses for the heat, that may be not so bad. But producing power from stored H2 at GW rates would produce more heat than is easily used on the same schedule as the power is demanded. The heat could also be banked underground, maybe, but there remains the problem of delivering it where it is actually needed.

I don't think you are even trying to read what they are saying. All they're testing is how well the hydrogen will stay underground and how tight the seal is for all of the various formations. We already know it works.

The only GW-scale H2 storage I find is the project in Utah, which starting 2025 and for the foreseeable future will be used to augment CH4 combustion to drive turbines.

It's the only one with real notoriety right now. But there are many projects. For example: https://www.business-live.co.uk/economic-development/equinor...

These appear to be carbon-capture CH4 extraction projects.

And, as in Utah, they seem to be planning to burn the hydrogen mixed into CH4 to drive turbines. The storage appears to be pumping H2 into existing CH4 wells, although it is hard to tell. I am anyway still not seeing any big H2 fuel cell projects, never mind solar/wind -> H2 -> fuel cell.

All of this is part of a large program by the UK to switch to hydrogen: https://www.gov.uk/government/publications/uk-hydrogen-strat...

What you're doing is just concern trolling, and suggesting that just because a program won't instantly get to zero emissions it is somehow not real. Meanwhile, electric cars are still being charged up mostly by fossil fuels, a fact that cannot change on the large scale without green hydrogen. Somehow, this fact is never brought up in every anti-hydrogen attack.

A gas turbine can get you up to 60% efficiency BTW. While fuel cells are arguably the better idea in the long run, it is not a huge problem to use gas turbines for now.

There are no "anti-hydrogen attacks", aside from Hindenberg scaremongering.

Instead, there are legitimate comparisons of hydrogen and other possible storage media. Harassing people for discussing such comparisons, and posting dubious assertions about hydrogen's maturity as a storage medium, does hydrogen and you no favors.

People have made the comparison and concluded that hydrogen is the answer. This is why there is now tens of billions of dollars in investment in hydrogen related technology. The naysayers are already proven wrong and now its turning into outright denial of current events.

I Googled around for this some time ago and found quite a few grid-storage projects in the US and Europe (both public and private), but I don’t have links handy at the moment. They all seem to be pretty early-days IIRC. But yes, mostly you have to sift through a lot of results related to transportation fuel cells.

If that energy would otherwise be wasted (because of an excess of supply in the market) then perhaps the efficiency doesn't matter so much.

It always struck me that 50% efficiency is better than 0%.

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