Cheap, green hydrogen would be a breakthrough in clean energy

https://youtu.be/MSZgoFyuHC8

You should clarify what an acronym means before using it tens of times.

If ever there was a process forgiving of intermittently available energy, it is chemical synthesis. The same money spent on wind and solar would produce a lot more ammonia.

Conversion losses don't matter much when marginal cost of generation is near zero, as we get with renewables, but very much not, with nukes. You just build out more panels.

- "Anhydrous ammonia is lighter than air and will therefore rise (will not settle in low-lying areas); however, vapors from liquefied gas are initially heavier than air and may spread along the ground."

https://wwwn.cdc.gov/TSP/MMG/MMGDetails.aspx?mmgid=7&toxid=2

Ammonia fuel cells have a comparable weight proposition to hydrogen at small sizes because the tank is so much lighter. I think that has legs (or wheels?). For stationary storage, the ammonia-CO2 adduct is a solid, which is nice.

That being said there is a lot of research both to generate ammonia from green energy, and the work to harvest ammonia for use as a fuel cell would benefit as a secondary emergent technology.

[1] https://iupac.org/what-we-do/top-ten/ [2] https://www.degruyter.com/document/doi/10.1515/ci-2021-0404/... [3] https://www.nature.com/articles/s41929-019-0414-4

Hydrogen (H) can be split from water (H2O) with a by-product of Oxygen (O). Hydrogen is hard to handle logistically (as discussed elsewhere in the thread), and the real idea in "Power to X" is to include Hydrogen in another molecule with better logistics. Main contenders are Ethanol (C2H5OH, alcohol), Methane (CH4, ~natural gas), and Ammonia (NH3).

Ethanol and Methane are by far the nicest products: already used as energy carriers, easy to handle, relatively non-toxic, but they have one problem: They require Carbon (C) to manufacture in addition to Hydrogen. Even with increased atmospheric CO2 levels, CO2 concentration in the atmosphere is only on the order of 400 ppm and extraction is expensive.

Ammonia (NH3) is synthesized directly from Hydrogen and Nitrogen (N) which is makes up 70% of the atmosphere. The Haber-Bosch process used for this synthesis is a cornerpiece of industrial chemistry.

I always find this false hydrogen versus batteries narrative bizarre.

Hydrogen fuel cell vehicles are EVs. It isn't an exclusive choice between hydrogen or batteries. Choose both hydrogen and batteries, both FCEVs and BEVs.

In any case, if you want your EV to be manufactured with green steel then you want hydrogen to be used in the production of that steel:

https://www.energy.gov/sites/prod/files/2017/05/f34/fcto_may...

https://arstechnica.com/science/2022/06/the-race-to-produce-...

No, or at least not by everyone. Hydrogen is seen as a replacement for natural gas. For example: https://reneweconomy.com.au/australia-japan-consortium-explo... There is no fancy fuel cell converting it to electricity in this plan. They are just going t burn it for heat, just as they do for natural gas.

Now there are a few problems, such as cost. Producing hydrogen costs around 4 times what it costs to produce natural gas. Or at least it did before the Ukraine broke out. Right now, if anyone was making renewable hydrogen, they would ge getting a tidy profit.

Another is storage. You can't economically liquefy it, it literally passes through metal walls and damages them on the way through. Converting to Ammonia is well understood, but getting hydrogen back was a problem. Until: https://www.csiro.au/en/research/environmental-impacts/fuels...

It might work. 100's of millions are being invested into finding out if it does.

This is not an insignificant advantage, to be fair. However, I agree that using electrolytic hydrogen as a Fischer-Tropsch or Sabatier feedstock is the way to go.

You've noted that temporal storage is a value prop of hydrogen. I'd like to add on that this is a real value prop driving real $B-scale spend at utilities in eg Los Angeles [1]. Depending on the researcher, hydrogen usually looks like the cheapest form of seasonal energy storage (vs eg iron oxide or flow batteries, excluding pumped hydro in ideal sites).

Hydrogen can move electricity around cheaply in space, and is arguably cheaper than HVDC for long distances [2].

If hydrogen can move electricity in time and space, that is kind of the holy grail for wind and solar. As you may know, there are endless square miles of CA/AZ desert and OK panhandle we we can produce power at insanely cheap prices, but we do not, because there is no cheap way to move power around in time and space. (And, because America can't permit those HVDC lines. We're much better at permitting pipelines.) If you believe in consensus cost curves for solar/electrolysis, you probably think that hydrogen will get cost-competitive with natgas @ $8/mmBTU in the next decade or so, then keep dropping. That's basically yesterday in utility years!

I'd also list "reliability" as a unique value prop, which is a key goal for grid operators with mandated zero-carbon timelines. This is a one of the things driving Los Angeles utility's acquisitions and cost/risk modeling. (There are other major factors: Utilities own lots of turbines and are building more, and can mostly start using hydrogen today alongside natural gas, and turbines fit their business model and operational expertise.) For these reasons and others, models of zero-carbon power systems are usually more expensive without hydrogen. That is, wind/solar/geothermal/hydro/nuclear/etc, plus 4-12h storage/batteries, tends to be more expensive than the same mix plus hydrogen. Example study at [3].

"24/7 clean energy" is another related concept, and is the holy grail for corporate energy buyers like Google. I haven't even brought up wind/solar interconnection yet, which is another problem which I see driving momentum for hydrogen, but that'll have to wait for another rant.

Thanks for reading!

[1] https://ww2.arb.ca.gov/sites/default/files/2020-07/ladwp_cn_... [2] https://www.sciencedirect.com/science/article/pii/S2211467X2... [3] https://www.nrel.gov/docs/fy21osti/79444-ES.pdf

Is that expected/known to be true even as the tech gets cheaper in 5-10 years? What's the level of confidence of this statement?

You can electrowin iron at about 80-90% efficiency.

I thought the same thing, but reading through the comments here makes me realize how many people seem to be completely unaware about the hydrogen discussion.

Is it? I always thought that it was always op-ex, because you need to burn two joules of energy, in order to produce one joule of hydrogen-potential energy.

Which, in a world where you can dig coal out of the ground for $30/tonne, is uneconomic.

For green energy, you'd need to literally store months' worth of energy somehow, and the cost of doing that via batteries is prohibitive too.

I guess the hope is that storing hydrogen, difficult and expensive that it is, could be made to be more like storing hydrocarbons, basically in a hole in the ground. Then you could produce it in the windy sunny months and use it in winter.

Maybe...

Four decades of climate change discussion and the single most important economic lesson to be taken from it, one that is absolutely basic free market economics, is still successfully suppressed and widely misunderstood, even in technical forums like this, full of people who think of themselves as libertarians. It's an impressively evil achievement for the fossil fuel producers.

I think that's an exaggeration, and neglects the possibility of overbuilding solar/wind. It may mean leaving your relatively low capital expenditure wind and solar farms 50% underutilized for half the day but the benefit here is that you can guarantee a 95% capacity factor year-round for the expensive electrolysis plant.

I'm looking at buying a base Model 3. Huge (57.5 kWh)chunk of battery that will be sitting there most of the week (wife and I both work from home).

Charging at 40c/kWh during the day (from abundant solar) and discharging at 85c/kWh (for evening peak) would yield about $23 daily - or $8,400 annually if the car was never driven.

https://www.sciencedirect.com/science/article/abs/pii/S03603...

1) If you take net zero as a hard goal, i.e. not one that is subject to economic tests except in relative terms then hydrogen as large scale energy storage only has to beat alternative technologies, regardless of how expensive it is.

Battery storage will absolutely dominate intra-day balancing and hydrogen will have no role to play there but the high cost per unit of energy stored of a battery doesn't work for inter-seasonal or for dealing with an unusually high demand year. (in a European context, a very cold winter for instance). No, future cost reductions will not solve that for the simple reason that the capital cost of a unit of battery capacity has to be recovered over its cycles. So a battery that cycles once a year incurs 365x the capital cost per cycle that one which cycles once a day does. In many renewable dominated power markets, current battery tech is competitive in the intra-day market. To be equally competitive in the seasonal market, you'd need two orders of magnitude cost reduction which doesn't seem possible on materials cost grounds alone. I don't see how iron-air and other battery chemistries stack up here either and to be honest, if we're going to compare long term energy storage technologies on a level playing field we have to compare like with like. We can't say "batteries" are getting much better and cheaper and are proven technology compared to hydrogen storage and then it turns out that the batteries in question are early stage VC projects.

When I look at the trajectory of grid scale battery storage vs hydrogen, I see a battery technology developing that will completely own the intra-day and probably the intra-week world but that has no chance of dealing with seasonal peaks.

Europe is prone to extended periods of cold, overcast, and windless weather which lasts for weeks and stretches from Ireland to the practically the Urals. That is the system stress condition and no system that cannot handle it can be said to be functional. The same might not be true everywhere, solar has less variation than wind and maybe California doesn't need seasonal storage, I don't know, but this is at least one area of the world which does and I suspect there are more.

Ideas which involve very long distance electricity transmission simply will not work for geopolitical reasons. If anyone fantasised about it before February of this year, they can now forget about it. No doubt electricity will be moved substantial distances but no government will allow the ability of its citizens to have winter heating / summer cooling to depend instantaneously on governments it cannot trust. Short distance integration of the kind we see in Western Europe, sure, but that doesn't really help because there's a lot of temperature, wind and insolation correlation between those countries anyway.

So hydrogen storage is lossy but the alternatives don't make the models stack up, except for a massive wave of nuclear new-build. I don't know which will be cheaper but these are both not cheap options. Proposed alternatives have to pass the test of dealing with this seasonal (and multi-year scale issue)

2) If you look at where power generation is going in high renewables markets, it is clear that we will soon have a situation where for many thousands of hours a year, we have deeply oversupplied instantaneous demand. That will be true even after intra-day load shifting, EV charging etc. This is in fact efficient since the cost of undersupply is asymmetric and vastly higher than the economic cost of oversupply. The system will be net long for most of the year and net short for a much smaller number of hours, during which period the value of dispatchable energy will be very high. More overbuilding shortens the net-short period but creates much more energy over-generated over the course of the year.

That means that your capital intensive electrolyser plant can run at full capacity the majority of the time, reduced capacity occasionally, and has to be off maybe 10% to 20% of the time. That is much easier to make work than 33%.

(I am assuming only modest electrolyser cost reductions)

The issues I have with a lot of analysis of hydrogen is that people do a quick order of magnitude comparison to either fossil gas or to batteries in the intra-day world and say, "why would you do this?" as a rhetorical question when they should be noting that fossil gas isn't a long term option, batteries aren't playing in the more than a day market at all (since there is currently no reason for such a thing to exist) and asking the question seriously rather than rhetorically.

People have been spoiled by the easy energy transition successes so far, moderately deep penetration of wind and solar into electricity and EVs and they expect that the whole energy transition will be delivered by technologies that compare favourably even without costing carbon emissions with the fossil fuels they displace and the reality is that we are not owed a set of technologies that are cheaper than fossil fuels.

For logistics reasons it will almost certainly have its place, but because by definition it takes a greater energy investment than just the hydrogen, it will economically come after hydrogen production has been scaled to solve the cases where it is not logistically constrained.

Or if your rocket runs on methane.

https://terraformindustries.com/ is just one example of companies going after this market. SpaceX is also getting into it.

(Efficiency isn't in the Carnot sense, and heat pumps move heat rather than generating heat... Semantics, but point stands.)

For example: I recall reading that it is more efficient (ie BTUs generated) to use natural gas peaker plants generating electricity to drive a heat pump than to run a furnace. (Except at very low temps where COP drops quickly.)

I thought batteries had some pretty toxic elements inside them? I don’t know much about using hydrogen as a power source so I’m interested to understand how it’s less green than batteries.

The target use case for hydrogen isn't the cases where you can use a battery. It's all the places where that doesn't work.

On the one hand, this is absurd: transmission lines are all over, are quite efficient, and work today. On the other hand, in some markets (cough California), the incumbent utility prices are rather divorced from actual costs. The ability to make hydrogen, move it on a truck, and turn it into electricity somewhere else, even at 40% overall efficiency, could be much less expensive than selling electricity to PG&E and buying it back elsewhere.

C) provide greater energy density allowing for heavy equipment, trucks, trains, and planes to use electric power.

Synthetic fuels have the enormous advantages that (1) tankage is super-cheap (negligible cost per kWh), (2) tankage is easily transported, (3) there is unlimited market for them, (4) you can burn them in existing combined-cycle turbines. These advantages easly overwhelm low round-trip efficiency, which is anyway relentlessly increasing.

We will be shipping hydrogen or ammonia from the tropics to Baltic states in winter. It is hard to imagine any viable green alternative, aside from reliance on fallible transmission lines.

Ramjet maybe? Or I forget if that is even hydrogen based at all.

Once LH2 aircraft enter any route, kerosene craft will suddenly be wholly unable to compete. But it needs abundant renewables, and synthesis equipment and underground tankage at airports.

Ammonia production, as I already mentioned in another reply, currently requires natural gas as as source of hydrogen.

Regardless of its use as a way of storing energy, it is already a very important industrial ingredient. Namely for fertilizer production.

As I see it, the only major problem with the current technology is that it might not be adaptable to new sources. New plants would have to be built.