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Comment by londons_explore | Hacker News Reader

The actual science:

> Here we report a catalytic system composed of 1-ethyl-3-methylimidazolium-functionalized Mo3P nanoparticles coated with an anion-exchange ionomer that produces propane from CO2 with a current density of −395 mA cm−2 and a Faradaic efficiency of 91% at −0.8 V versus reversible hydrogen electrode over 100 h in an electrolyser.

This is almost too good to be true... they demonstrate commercially viable reaction rates, efficiencies and timescales.

They have presumably applied for a patent for it, so in 20 years when the patent expires this will become the standard thing to do with recovered CO2 I'd guess.

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> in 20 years when the patent expires...

Well, only if the patent-holder makes no effort to maximize the return on its investment in those 20 years. But if the technology is really that effective and the patent-holder is even a little bit economically rational, then presumably the patent holder will be the one pushing hardest to make this the standard thing to do with recovered CO2 well before the patent expires.

Not that patents are all roses and puppy dogs. But this is too big a part of the picture to just ignore.

The patent-holder has licensed the technology to company with a large sunk cost in handling petroleum from the ground. I suppose SHV Energy could decide to put up a solar farm driving CO2 -> C3H8 catalysis, but where's the money in it for them? I would like to be happily surprised, but my guess is it's some form of green-washing.

That’s backwards is it not?

A fossil fuels company has deep incentive to minimize the harm of fossil fuels. A solar company has incentives to make fossil fuels as bad as they can.

Even if you generally perceive fossil fuels guys as bad guys.

Regardless. Any company has incentives to do this if someone (government) will pay for it. It doesn’t really harm any profits.

> A fossil fuels company has deep incentive to minimize the harm of fossil fuels.

They have a deep incentive to capture the regulatory framework that might hold them accountable for that harm, which they have accomplished.

Yes, the sentiment is so completely ignorant of what they have actually done during the last four decades that I'm now on like the third or fourth take...

Right, and the ones who are best able to figure out regulations are, of course, the businesses themselves!!

Look how well that's worked out for the financial sector. Nothing but good faith actors there. Immaculate.

I’m not saying fossil fuels companies should be in charge of regulating fossil fuels companies.

I’m saying that fossil fuels companies are incentivized to sell useful co2 converters because this enables them to sell more fossil fuels.

> A fossil fuels company has deep incentive to minimize the harm of fossil fuels

You... you're aware that the actual, historically realized, attitude of fossil fuel companies has been to deny any harm exists, right? Deny it to the tune of 200 million dollars as recently of 2019, and for good reason! That spending bought them lots of political inaction since the science was settled in like 1990, you know: the days where keeping staying below 1.0 degrees warming was a realistic goal.

what is historical fact compared to what my imagination tells me should have happened?

I am aware of that, yes. This doesn’t change the calculus of today.

CO2 conversion tech is a path to selling more fossil fuels.

Why spend on tech that might not be a sure thing when bribery has been working for decades?

Because that’s a gross oversimplification of things that sounds punchy but isn’t particularly realistic.

Okay explain for us the realistic mechanism by which CO2 conversion technology allows oil companies to not only sell more fossil fuels than they do now, but most importantly does so with a greater ROI than the open bribery that our institutions not only allow for but actually require to function.

Because it sounds to me, speaking of "punchy but not particularly realistic" that you have some idea in your head of how our politics and economics work, that is contrary to even a cursory examination of material reality, and is laughably naive. And I earnestly want to hear it, because I could use a laugh today.

> Because it sounds to me, speaking of "punchy but not particularly realistic" that you have some idea in your head of how our politics and economics work, that is contrary to even a cursory examination of material reality, and is laughably naive. And I earnestly want to hear it, because I could use a laugh today.

Could you please not.

You are presenting a false dichotomy. It’s not “bribe vs. use this tech”. It’s also not really about bribing at all. Fossil fuels are important. That sucks, but we do need them in the short term.

If this tech works, and the government is willing to pay for it to some extent, it’s probably a lot cheaper to build caseload gas plants and peak daytime load renewables than it is to try and build excessive green power and batteries to tide the night over.

Or just, you know, worst case run this profitable service independently of externalities

Or you could just sell more fossil fuels.

Why? Why not just sell more fossil fuels?

No they've decided to go the route of tobacco companies, deny everything and party while the sun is shining. By the time the lawyers show up they're counting on being dead or too old to stand trial.

Carbon credits. Tesla was only viable in the early years all due to carbon credit purchases.

> They have presumably applied for a patent for it

They have one in this space: "Methods and devices using tri-transition metal phosphides for efficient electrocatalytic reactions" at https://patents.google.com/patent/US20220154354A1/en with abstract:

] Methods and devices for generating hydrogen gas with an electrocatalytic energy conversion cell by introducing a tri-transition metal phosphide catalyst at or on an electrode of the electrocatalytic energy conversion cell. The electrocatalytic energy conversion cell includes a first electrode including a tri-transition metal phosphide catalyst, such as MO3P, a second electrode of an anodic material, an electrolyte disposed between the first electrode and the second electrode, and an electric potential source connected to both electrodes. Oxidation and reduction reactions, such as hydrogen evolution reactions, occur at the first electrode.

(Google Patents says "M03P", the PDF says "MO3P" in the abstract, but the text clearly has "Mo3P".)

Even if this isn't exactly the technology discussed - Supplementary Figure 20 shows how ImF-Mo3P catalyst improves on "pristine Mo3P nanoparticles" - the authors have several other related patents, so I have no doubt a patent was filed for this technology as well.

Recovered CO2 if it's recovered from the atmosphere. Essentially all concentrated CO2 today is recovered from fossil fuel consumption, and while turning that into propane and then burning the propane (in a ship or home furnace, e.g.) would get double duty out of the carbon, it would still release it into the atmosphere. So, the real question is the combined efficiency of carbon capture from the atmosphere + catalytics propane production followed by propane combustion. It may pencil out for processes that require combustion heat, or where the portability of propane vs electricity are a huge win. Maybe as a storage medium for electricity production between renewables. All depends on numbers.

If you capture the CO2 produced when burning the propane, you can get more than double duty. If you used this process to store energy into propane when electricity is cheap, and then produce electricity by burning propane when electricity is expensive, you could potentially have a system with close to 0 CO2 emission. Compared to batteries, storing propane and CO2 even for months looks very cheap.

Organic reactions have a very low efficiency. Most of them only less than a 50%. Batteries have a better efficiency in the conversion.

At some point, cheap trumps efficient.

Propane is easy to store, easy to transport, propane storage tanks are cheaper than batteries, require no high-tech manufacturing or rare earth elements, and I'd guess the energy storage density is higher.

Many (most) existing cars could be converted to run on propane and the engines will last longer and emissions will be lower as it's a cleaner-burning fuel.

Some newer battery cell chemistries are using very very little rare earth elements

A propane tank is basically just the hollow shell of a battery, made of even cheaper mild steel since weight is far less of a concern. There's no contest in this department.

Not that I'm in favor of combustion engines persisting.

I’m not saying your arguments don’t hold. Just that the calculations may be closer than stated

Humanity uses around 25 000 TWh of electric energy yearly.

With batteries storing that is technically possible but it would take the whole world decades to build the required infrastructure.

With propane or other similar hydrocarbons it's around 2 million tonnes. 4 million if you account for 50% efficiency of turbines (we have better ones BTW).

4 million tonnes of gas seems like a lot, but currently USA has about 5850 bcf (1.6*10^14 liters) of underground gas storage ready, at 1.8 kg per m3 you could store about 300 million tonnes of propane. Enough to power the electricity grid of the whole world for 75 years.

So it's a choice between spending billions and turning our whole industrial output to it for years - or just using a fraction of what's already there in a slightly different way :)

Another point is - once you have one kind of hydrocarbons - you can burn them in adapted ICEs or transform into other hydrocarbons to be able to use existing cars. Suddenly you can continue to use the whole infrastructure we built in the last 100 years as if nothing happened with net 0 carbon footprint.

It's the only thing that makes sense, really.

I think that you slipped some decimal places.

Propane has a thermal energy content of 13778 watt-hours per kilogram [1]. That's (25000 * 10^12) / 13778 = 1,814,486,863,115 kilograms, or 1.8 billion tons. 3.6 billion tons of propane if you recover electricity at 50% efficiency. That would make the 300 million ton underground storage equivalent to one month of global electricity demand. That's still a lot of storage, of course.

[1] https://en.wikipedia.org/wiki/Energy_density#In_chemical_rea...

Thanks, should have double checked. I always mess up long and short scale when combining from different sources.

Yeah, it's going to be a long time before we can get completely away from hydrocarbon fuel. There's nothing that comes close for energy density for something that is practical to use. (Hydrogen beats it considerably but comes with a million headaches. There's a reason SpaceX doesn't use hydrolox engines despite their considerable performance advantage!)

Thus we should be looking for efficient ways of turning clean energy into hydrocarbon fuel.

Ah, a perpetual motion machine.

This assumes that co2 recapture and propane synthesis require less energy than is produced by burning propane.

This is maybe a workload for excess solar, making renewable propane with electric that would otherwise be wasted

I think the suggestion is that it's a battery with low long term storage costs, not that it's 100% efficient round trip.

Sure, and that is an option if you're using propane as storage for renewable electricity, or for large scale industrial uses like cement production. You won't get to full recycle, but you can get close. It's not an option for propane as transportation or heating fuel, however.

It’s kind of annoying that this is always brought up as a gotcha. Direct air CO2 capture is not a massive contributor to the total energy usage. It’s still dominated by electrolysis itself. The numbers aren’t that hard to find, either. A kilogram of propane has a specific energy of 50MJ and emits 3kg of CO2. Assuming this electrolysis is 50% efficient, that requires 100MJ to make. CO2 direct air capture is about 4.3MJ/kgCO2, or about 13MJ/kgPropane compared to the 100MJ/kgpropane of electrolysis. So it’s still a pretty small fraction of the total energy costs.

EDIT: note that burning that propane in a cheap generator is only gonna net you 10MJ/kg of electricity, maybe 17MJ/kg in a large expensive generator. So the roundtrip efficiency is just 9-15% efficient. But it potentially saves you a LOT in storage costs if you’re only cycling this storage once or twice a year.

(Note that propane is a great way to store hydrocarbons as the pressure is low but it’s self pressurizing and thus it doesn’t get water ingress or have any of the storage difficulties of gasoline and diesel, which last only 3-6 months or 6-12 months respectively. It’s also very clean burning compared to those two.)

I wasn't looking for a "gotcha." Just saying that you need to consider all the input costs to know how this pencils out.

50% is almost exactly the paper's claimed efficiency for the lab cell, so it's a reasonable number.

Overall, I'm very enthusiastic electrocatalytic methods for producing hydrocarbons as a combustion fuel source for applications where direct electric technologies are not feasible. I'd much rather seen money and energy going into making something like this work, than all the effort on hydrogen. Propane, or any hydrocarbon in the 3C-8C range, is a way better fuel for any fossil fuel replacement energy system than hydrogen.

The remaining issue is the durability of the catalyst.

They demonstrate 100 hours. That's plenty for commercial viability - replacing the catalyst every 4 days is very doable. And it's likely that the catalyst lasts far longer but the experiment only went on 4 days.

Especially if it can be regenerated, then it's really a non-issue.

>The remaining issue is the durability of the catalyst.

And its cost.

Or more generally, where the catalyst sits in the supply chain (how easy it is to produce at scale, can it be recycled, is it expensive, what is the waste management for it, etc...)

1-ethyl-3-methylimidazolium-functionalized Mo3P nanoparticles don't sound very off-the-shelf...

The question is can we make it cheaply enough at the required scale. Lots of things area off the shelf today that were not in the past. Other things used to be common and are not made anymore.

Chemistry can sound complex, but the compound mentioned is relatively simple for an organic chemist. Metal nanoparticles are fairly routine. Since this is a catalyst, not that much would be needed (relative to the likely difficulty of making it). Probably a rounding error in terms of the expense of the entire system.

How much CO2 is generated to make one is the other question.

Can you please explain these numbers of layman terms?

Let's say my car burns equivalent of 100kWh worth of LPG, how many kWh of propane i can recover from the exhaust gas and how many kWh of electricity i need to provide for that?

You wouldn't recover the propane at the exhaust of the car. Instead, you'd have a fixed hydro/solar/wind renewable energy installation, spending ~25 kWh on an atmospheric capture program, or less if you can get it from more concentrated flue gasses coming off an industrial furnace/ammonia plant/cement plant, and then ~200 kWh to convert that CO2 by this process into 100 kWh worth of LPG.

It's not viable (in terms of energy availability, packaging, or economies of scale) to run that sort of cryogenic high-pressure CO2 purification and storage system on the exhaust pipe of a vehicle. I could maybe imagine a solar installation with this attached being viable at, say, a remote farm with LPG-powered agricultural vehicles, or if I stretch my imagination to scifi timescales (and think about the number of remarkable compressors installed at scale in HVAC systems) to suburban homes with rooftop solar.

I don't think it's ever going to be viable at the suburban level. However, for off-grid use I can definitely see it making sense. Large scale batteries for photovoltaic use make off-grid solar quite expensive on kWh basis. This is considerably less efficient (although I think you could up the efficiency with a turbine generator) but costs scale on throughput, not on capacity.

You'd need to spend at least 110kWh to convert CO2 back to propane, maybe much more. No matter what you do, LPG -> CO2 -> LPG cycle has to be energy-negative.

Not sure people really want that much propane. But really, this kind of process is still being pursued for e-Fuels despite horrific economics

https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...

The economics are so awful because of a complex network of reactions, there are processes that build up larger hydrocarbons and break them down and you have to balance these just right to get liquid fuels and not paraffin wax or methane. Some kind of single-entity fuel has always seemed to make more sense to me: methane isn't that good of a destination because it's not that easy to handle or liquefy, propane is quite easy to handle in comparison.

Hopefully any patent will not be granted. That's not how you make progress. Understandable that competition would have a head start without incurring the substantial R&D costs, but we should rather strive to make R&D tax deductible, rather than maintaining harmful patent system. This way business that incurred substantial R&D expenditure could claw it back from the sold product. This also incentivises businesses actually using their R&D rather than shelving a patent and then going on fishing expeditions to see if someone come up with the idea independently and executed it only to slap them with a lawsuit.

Patents? Nope.

> They have presumably applied for a patent for it, so in 20 years when the patent expires this will become the standard thing to do with recovered CO2 I'd guess.

And how many years would it have taken if a patent wasn't an incentive?

It’s a public university, and government funded research. so fewer?

The history of everything from MIPS to BBN shows that a major piece of the puzzle is creating incentives for high caliber people to go into public university research, and then invest in commercializing the resulting technology. The government funding only provides the kickstart.

Or in less than 20 years when the patent is licensed. No point in sitting in it for 20 years.

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