Electrolyzer efficiently converts CO2 into renewable propane fuel | Hacker News Reader

Electrolyzer efficiently converts CO2 into renewable propane fuel

scienceswitch.com

335 pointsconse_lad329 comments

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.

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.

> 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.

> 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.

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.

> 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.

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.

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.

There’s no clear indication whether that would require some CO2 or a concentrated atmosphere of CO2 without O2. Extracting CO2 from the atmosphere at 0.4% is expensive.

If this is meant to use concentrated CO2 coming out from a furnace, would that need to be local, piped in over a long distance, or using bottles? Are there use cases where we must burn propane because we can’t replace that process with electricity?

"Must" is debatable, but I've got a propane patio heater of a fairly common model here (NL) that tops out at 13000 watts.

If it were electric it would require a 13k/220 = 60 amp connection, triple the domestic wiring standard here.

You’d need a lot less power if you use infrared lights…

Still: better grid connection or home batteries are much less complicated to install than a whole new CO2 conversion set-up, plus we are going to need those if people are going to drive electric cars. The cost (energy or money) of capturing CO2 in the atmosphere into concentrate for that catalytic process.

You have a lot of industrial processes that produce highly concentrated CO2 - for example, cement production which is responsible for about 8% of worldwide CO2 emissions.

I’m not convinced that the overall cycle is sustainable: cement >> concentrated CO2 >> electrolysis >> propane >> burn into the atmosphere still leaves that 8% of CO2 in the air.

It replaces equivalent 8% of CO2 from fossil fuels that would be burned otherwise.

Cement is absorbing some of that CO2 back when it's curing. Some of CO2 is emitted by processing (crushing and heating), that part could be eliminated by renewable fuels, some is inherent in making cement (releasing CO2 from limestone) but most of that part is absorbed back during curing. There are also carbon-negative alternatives in works[0]. That propane from cement could be used for synthesis of other materials instead of oil (not used yet because it's not needed only because we have cheaper oil) instead of being burned.

[0] https://www.theguardian.com/environment/2008/dec/31/cement-c...

We will need all the electrification we can get for electric cars and heat pumps. offloading some of that to other energy sources, using pre-existing infrastructure, would be amazing!

Patio heaters: for when the planet isn't warming fast enough and you want to pump heat directly into the atmosphere.

That's good.

But also a bit misleading. Pumping heat into the atmosphere isn't really at the heart of climate change - adding insulation to the atmosphere is. It probably isn't great to pump heat into it either, but the mechanisms for radiative loss of that extra heat are (were) pretty good, and it would take a gigantic amount of heat (more than we've produced by burning fossil fuels) to shift the energy level in the atmosphere by much over longer time frames. However, effectively adding another blanket to the atmosphere is far more impactful. Last credible estimate I saw was the atmosphere now contains about an extra 8 peta-watts compared to pre-industrial times, and almost all of that comes from a reduction in "radiative forcing" (loss of heat to space, essentially) rather than additional heat generation.

Yes, the amount of heat added to the atmosphere by human activities is negligible compared to what we receive every day from the sun.

It's the heat that is retained that is the problem.

This is true, but it's also explaining a joke. The real point is that patio heaters are necessarily very inefficient because they're operating in an uninsulated space that's open to the elements - almost all the heat will be immediately lost to the atmosphere. Heat lamps are better, but really patio heaters are used by people trying to cosplay an outdoor culture at a latitude or season that doesn't support it, and they should put some warmer clothes on or go inside.

Your final observation might be true of parts of the USA. But go to Berlin in winter, or anywhere in northern Europe really, where "it's cold" and "being outside" are not considered oppositional. Take a winter walk down a Berlin street with outdoor restaurant seating, and see people sitting under blankets, with warm coats on, and hats ... enjoying dinner ... and patio heaters.

They are not cosplaying at anything. It's just how it is.

Patio heaters (at least the gas-powered kind) are prohibited in most German cities. Berlin has only temporarily allowed during Covid, as far as I know.

> It's just how it is.

It's a fairly new trend, and as mentioned above, one that's probably already over. Germany has had outdoor Christmas markets for much longer than patio heaters have existed.

I lived in Berlin in 2008/2009. They must have been banned since then, because they were very common at that time.

And yes, the christmas market version of being outside is obviously much older, but in my experience (also, Heidelberg in 1986) was less sitting around and more moving around outside (or in heated tents).

Patio heaters should be illegal.

> Are there use cases where we must burn propane because we can’t replace that process with electricity?

Yes. Ships, for one - no way you can power an oceangoing large ship with batteries for the entire trip, but doable with LPG (which is essentially a propane/butane mix). Assuming that further technology (chemical or biotech) gets developed to combine it to form larger hydrocarbons, it can also be used as a precursor for airflight synthfuel.

One ship could always go nuclear, or use wind.

Russia tried that for nuclear, it wasnt a success.

Though that was because it was badly mismanaged and the technology wasn't there yet.

Wind doesn't work with container ships, the sails are in the way of the cargo cranes at port. Might be an interesting idea for passenger ships though, but even there... there are ports which have a height limit (e.g. Hamburg) because ships need to pass below bridges.

Nuclear in civilian hands is an absolute no-go for proliferation / terrorism concerns.

Someone should tell theses guys about wind power.

https://www.cnn.com/2023/08/22/travel/wind-powered-cargo-shi...

Yep, and those smartly can fold down! Also used for storms I assume.

Those only provide about 30% of the ships power.

Well there are cranes at the port, make the sails detachable and dismount them to load.

2 proposed solutions for wind are

1. Kites attached by cable (deployed, high altitude for consistent winds)

2. Magnus effect cylindrical turbines that rise out of the ship.

Civilian nuclear-powered cargo ships have actually been tried in the past, a large issue was that a lot of ports refused them entry if I remember correctly.

There's also the minor issue that they are, like most forms of nuclear power, hellishly expensive.

Several have been built and people have generally gone "huh, thats cool but it's way too expensive".

Thats the main reason why theres currently only 1 in the whole world.

They are expensive because they don't externalize their environmental costs upon the rest of the world.

The environmental costs of renewables (other than biomass) are minor.

There could be nuclear “tanker” ships that recharge electric battery ships on their routes.

Nice picts and walkthrough [0] of the NS Savannah, "the world's first, and only, nuclear-powered cruise ship. The Savannah is the only nuclear-powered merchant ship the U.S. ever built, and the only nuclear vessel in the world designed with passengers in mind."

[0] https://www.npr.org/2023/06/23/1182973358/step-aboard-the-nu...

I don't that that's the major issue. At least, the Wikipedia entry for the NS Savannah only mentions being excluded from Australia, New Zealand and Japan.

https://en.wikipedia.org/wiki/Nuclear_marine_propulsion#Civi... comments the major issue is the costs of specialized infrastructure, and points out how research about a modern design concluded "further maturity of nuclear technology and the development and harmonisation of the regulatory framework would be necessary before the concept would be viable."

A fuel-powered ship can ramp output up and down as needed, since the per-power costs of the powerplant aren't that high.

Nuclear power plants are much more expensive, and require a much higher (and more expensive) level of labor. These fixed costs are not reduced when full power is not needed.

Yup, this is the headache with nuclear--your marginal costs of generating power are very small (and I wouldn't be surprised to learn they're negative as big machines prefer to run at constant settings--it wouldn't shock me one bit if throttling it up and down causes more maintenance cost than fuel savings) and thus it's only sensible in environments where 100% throttle is useful, or in environments where cost isn't an important driving factor (military vessels) or fueling is problematic (IIRC Russia had a nuclear-powered icebreaker.)

Put your reactors on land, when the grid has too much power you direct it to something like this (or the hydrogen generator that showed up here a few days ago) and convert it to chemical energy.

Liquid hydrogen or ammonia are both very much feasible and carbon-free.

Both Yanmar and Kawasaki are developing large marine four-stroke piston engines for hydrogen, with 2025 as launch date.

Ammonia-fuelled piston engines are easy, their only problem is idling due to the poor combustion properties of ammonia, which you can solve in the pragmatic way by using a little hydrocarbons during idle - combined with power from shore during docking, that still gets you >95% emission reductions.

Hydrogen has the problem with thick-walled heavy fuel tanks - problematic for both cars and planes.

Ammonia to my knowledge has a problem of both potential toxicity (both if gas escapes in refuelling and NOx emissions after burning) and needing enriched pure oxygen rather than running with atmospheric air.

Propane or other hydrocarbons look superior to both of these to me.

Hydrogen has problems, but at the end of the day it's viable and are the best option for planes/ships if we don't find anything better. On ships fairly easily, on planes with a fair bit of re-engineering. Local pollution aside, renewable hydrocarbons would be a better option, if they're viable at all.

Green hydrogen is still horrifically expensive, wind powered cargo ships are currently more valuable though not actually viable without a massive carbon tax. Batteries can provide enough power for ships electrical systems. There’s some niche fully battery powered boats which work fine for trips up to a few hundred miles.

A full EV transition would also free up quite a lot of biofuels. Not enough on its own, but still significant.

Green hydrogen is expensive, yes, but less expensive than synthfuel. I'm not thrilled at the prospect of a green hydrogen future, but it's our best option for replacing fossil fuels currently, and so is what we should adopt if we can't come up with a better solution in the next 10-20 years.

To my knowledge wind-powered cargo ships can only supplement cargo ships and can't fully substitute for a proper fuel source, but I would absolutely love to be proven wrong.

The bulk of biofuels are a dead end (although some types of biofuels are valuable in recycling waste products), because modern agriculture basically just turns oil into food; BEV tractors basically don't work due to the range and charging-times needed on an already very heavy vehicle.

BEV tractors work fine with hot swapping batteries. It’s not perfect in every single way, but there are significant benefits to offset the downsides. EX: “Monarch also offers a battery swap cart to keep the tractor running and uses 90% fewer moving parts than a comparable diesel unit. ” https://www.agweb.com/news/machinery/new-machinery/future-el...

I don’t think green hydrogen or synthetic fuel is a realistic option yet. As to a fully wind powered boats, the last fully wind powered cargo boat used commercially lasted until the 1960’s it lost but not by some huge margin. So yes fossil fuels win, but they don’t win by such a huge margin that a fuel costing 4x as much also wins.

Hybrid battery/solar + wind boats are still a common thing for houseboats and pleasure craft in part because of the cost advantages. At even a 2x cost bump over bunker fuel I suspect bulk shipping would start to go a similar route. Militaries and billionaire super yachts might go with hydrogen or synthetic fuel’s it just a question of how quickly their prices fall.

I don't think you fully grasp the sheer inability of batteries to power a cargo ship. It is something like 50x too low energy density to work. Even with wind power, it is still far from being able to pull this off. Not to mention cost: The batteries will be many times more expensive than the ship itself. The whole idea is totally DOA.

It is going to be some kind of chemical fuel, it is just a question of what and when. The alternative is just people not doing their physics homework and being totally wrong.

The batteries power electronics for navigation, communications, and ship’s systems like moving the tiller. That’s a tiny fraction of the energy needed for large cargo ship propulsion.

Wind is what provides power and scales incredibly far, we already have individual floating 16MW wind turbines. The very largest ships are approaching 60MW, but rarely operate at full power instead “slow steaming” to conserve fuel. https://en.wikipedia.org/wiki/Slow_steaming

The cost of the ship alone is irrelevant if you’re trying to sell fuel at 4x the price almost nobody is going to be willing to pay when they’re not even willing to pay full price at todays fuel prices instead choosing to travel slower than sailing ships while still paying for fuel.

PS: As to battery weight, ships scale really well around weight which is why we have ships moving 200,000+ tractor trailers worth of cargo. There’s fully battery powered ships traveling hundreds of miles for local delivery to remote areas. Which actually means going from Asia to Europe or Africa with some battery swapping is viable. Higher upfront costs and extra stops, but drastically reduced fuel consumption.

You're not putting anything like a 16MW wind turbine on a cargo ship. That thing is practically larger than the ship itself. Nor do wind turbines generate 16MW continuously. This is all just handwaving the fundamental problems away.

You're going to need chemical fuels to solve this problem. You really have to get to grips with basic physics here. Global warming can't be solved by science deniers.

PS: How are you going to battery swap on a ship? Nevermind the cost of such a thing. This is just another absurd idea stacked top of an already absurd idea.

Cargo ships swap 40’ containers at ports, many of those have electrical hookups for internal cooling. So, doing the same thing with bigger batteries and thicker cables is hardly a massive feat of engineering. You don’t even need charging infrastructure in port, toss them on a trick or train and charge em wherever is cheap.

I am not suggesting a wind turbine is an ideal fit for a cargo ship just mentioning how much power we’re already extracting on floating devices that move with the ocean.

Ultra slow steaming is 40% of max power for a 46MW cargo ship that’s 24MW so we’re in the ballpark what comes next is hardcore engineering by companies who understand the industry and they say the math is really close to working at current fuel prices. It’s you who wants people to swap to ultra expensive fuels and I’m just point out that “bunker fuel” > wind but wind > ultra expensive fuels.

And how do those cargo containers get charged? Or how can they be connected together so easily? Or how much cargo space will get taken up them? Nevermind the cost of all of that.

Again, the wind turbines you are suggest are far too big for a ship. It is totally impossible. You are not going to get more than a tiny percentage of power from wind from this. At best, you are just going to have literal sails that take off some of the power demand from the engine. The ship will still have to be powered predominately by chemical fuels.

Look, you're flat out denying the physics of this problem. You cannot solve this problem with science denier. You are doing the same thing that climate change deniers are doing.

If you want a green solution they get charged from a solar or wind farm sitting near the port. Solar farms are already being built with large battery systems to better fit the demand curve, adding extra PV and batteries to the mix is a win/win for the electric grid. Edit: Nuclear power is also viable if land is in limited supply in the area, generally more expensive than solar but still way cheaper than fossil fuels.

“Flat out denying the physics of this problem” you’re arguing that sailing ships don’t work.

Maersk the largest shipbuilder in the world already got flettner rotors to provide useful levels of propulsion, ADD a kite system and you’re traveling faster than commercial shipping doing slow steaming. As I’ve said repeatedly they don’t quite work at current fuel prices, but you want to increase fuel prices.. Read up on: https://en.wikipedia.org/wiki/MS_Onego_Deusto for why kite’s didn’t take off it was all about the economics not the underlying physics.

PS: Without paying for fuel the economics changes enough we probably aren’t going to see 200,000+ TEU ships and routes would optimize for winds. But that’s not an inherent problem it’s just a tradeoff, perhaps we invest in larger port’s that just an expense not a deal killer.

> If you want a green solution they get charged from a solar or wind farm sitting near the port.

This is just you handwaving the problem away. You will need a very reliable supply of energy for this. It actual makes more sense to convert that green energy to something like hydrogen for powering ships. If done at scale, cost will be not much more than the cost of the wind and solar energy itself. Which is potentially very low. And nevermind the fact that you have nowhere near the capacity of batteries to power your ships.

> “Flat out denying the physics of this problem” you’re arguing that sailing ships don’t work.

The largest sailship ever has a displacement tonnage of around 5,000 tons. Modern cargo ships are closer to 250,000 tons. Sailships don't work at the scale you're imagining them. It is basically going back to the 19th century in terms of shipping capacity.

> Maersk the largest shipbuilder in the world already got flettner rotors to provide useful levels of propulsion, ADD a kite system and you’re traveling faster than commercial shipping doing slow steaming.

Skysail just reduces fuel consumption somewhat. It also seem to have disappeared as a serious idea about a decade ago: https://www.ship-technology.com/features/feature-skysails-br...

> You will need a very reliable supply of energy for this.

Solar is extremely reliable as long as you have an oversupply when all you want to to charge batteries. At sub 2c/kWh it’s highly variable but build in 50% extra and you’re only at 3c/kWh and now very consistent across a full week. Obviously, there’s varying tradeoffs so if the cheapest solution is to stick them on a boat and charge em in another country that’s what would end up happening. There’s also obviously tradeoffs between moving shipping containers vs moving electricity but again that’s an optimization problem not some inherent limitation.

Skysail isn’t viable at current fuel prices, the technology works just fine. Current sail designs are of limited value along current routes, but those routes are also optimized for fossil fuels.

Club Med 2 built on 1992 was 15,000 tons and a quite traditional design for aesthetics, again Skysail can significantly boost propulsion. Thousands of economically viable modern cargo ships are 50,000 ton panamax ships and plenty are well below that, those 250,000 ton monsters are an economic optimization between a handful of major ports not some inherent requirement.

The total crew size is largely independent of cargo size, but even relatively small ships are moving 100’s of TEU per worker. At that point it’s only a question of what’s the most efficient design economically not what’s the largest ship.

Uh no. You are looking at a 20% load factor with solar, plus massive seasonal variations. It is completely non-doable with batteries.

Seriously, you seem like someone who is obsessed with doing it with batteries, not a person even remotely interested in finding a working solution.

Meanwhile, the alternative, just making hydrogen with the same renewable energy source and powering your ships with it, is sitting right there as an obvious answer. If you already admit to the existence of $0.02/kWh electricity, then the rest of the cost equation is also going to be low here. You've already solved the economics of the issue. The rest is scaling up, and this time there is no need for sails or downsizing ships.

Do you forget what we were trying to do? The explicit goal is charging batteries in 40’ containers and clearly PV isn’t working at night so what matters is consistency during the daytime. A flat panel on a rotating circle has a maximum theoretical capacity of diameter/circumference = 1/pi or 31.847…% on earth it’s more complicated due to axial tilt etc, but what matters is how consistent the output per day not the number of minutes per day we’re getting power.

Real world capacity factor Capacity factor 27.9% (average 2017-2019) https://en.wikipedia.org/wiki/Copper_Mountain_Solar_Facility that’s surprisingly close to the theoretical maximum for the location and design. Some break 30% but again it’s not about maximizing output just how much it cost to guarantee we can fill X TEU worth of shipping containers per ~week. Thus it don’t matter if there a 18 hour period one day when they aren’t being charged as long as you can charge enough on average.

> Meanwhile, the alternative, just making hydrogen

Sure let’s pay vastly more per gallon that’s an easy selling point. Hydrogen has maximum limits imposed by physics that severely limit end to end efficiency. It’s a dangerous bitch to store, transport etc. Low density, damages metals it comes in contact with etc, even rocketry got away from the stuff even though it has significant advantages for them.

Nobody is using the stuff because it’s got huge problems.

Have you forgotten what your goal is? It is to get ships to zero emissions. Not force a physically nonsensical idea onto the shipping world.

You've already admitted that solar is just $0.02/kWh. You can do the rest of the math and realize that hydrogen will also be very cheap. You're entirely thinking in cliches now. It is "battery = cheap, hydrogen = expensive" despite your own argument contradicting that claim.

In reality, people will just some kind of chemical fuels. If not hydrogen directly, then something derived from it like ammonia or synfuels. It is already happening in fact, and your obsession simply won't happen.

I call green hydrogen expensive because that’s what it actually costs today. There’s a reason we only get 4% of hydrogen from electrolysis, it costs more than using fossil fuels.

Look at hydrogen fuel station pricing sometimes even using fossil fuels and compare costs vs bunker fuel. There’s projections it could possibly get close to US gas prices in 20 years, but that includes road taxes, high refining costs, transportation, etc and are therefore much higher than bunker fuel actually used by boats. So the optimistic projections are doubling a ship’s fuel costs and current prices are much higher than that.

As to your “nonsensical idea” complaint, companies actually saving companies money today using it. This isn’t some hypothetical, actual ships on the ocean are using large scale batteries to save on fuel costs. Further, the absolute largest car carrier in the world is smaller than the largest sailing vessel ever built, they load and unload from the front so sticking sails on top wouldn’t be a problem. Fossil fuels are cheap, but hydrogen isn’t viable today which is why ships aren’t using it and it’s not projected to be viable for decades. Anyone who tried using hydrogen would simply be eaten alive by the competition.

You could've said the same thing about anything before it hits mass production. Wind and solar were expensive too at one point. It is not much of an argument.

The thing about hydrogen is that is made from an extremely plentiful resource: water + green energy. That puts the cost floor at below that of bunker fuel. In fact, the cost floor is pretty close to zero. So you are basically repeating the generic "renewable resources can never be cheap" argument. But it has been discredited.

Nobody uses anything like a battery powered ship for long distance travel. You are making up imaginary scenarios.

Clean energy isn’t free nor is the actual infrastructure required. Round trip efficiency for hydrogen is currently ~18% excluding horrifically expensive fuel cells which are completely off the table for these ships. On top of this you got to pay for the infrastructure to actually make the hydrogen + infrastructure to store the stuff + the increased costs of building ships to handle it.

Even optimistic estimates put Hydrogen well above bunker fuel.

> Nobody is using anything like a battery powered ship for long distance travel.

Cargo ships with hot swapping batteries are already in use. At that point it’s Europe to Asia is an infrastructure problem not a research problem. People hope to eventually solve Hydrogen’s issues with production and storage but have made minimal progress over the last 20 years. Just because we want technology to work doesn’t mean it’s actually possible to build it.

Hell just look at how much people have hyped up Nuclear as a source of cheap electricity as long as we invest in more R&D. Except even with huge investments in new designs etc there’s been zero actual progress in lowering costs.

Clean energy is regularly free or even negatively priced. It is at the very least, extremely cheap. It's funny how PV panels at 20% efficiency never stopped it from catching on. Making the same accusation against hydrogen is just repeating this already debunked argument.

The whole infrastructure for hydrogen will just repurpose or modify natural gas infrastructure. It is not expensive. It will be vastly cheaper than trying to do it entirely with batteries. And without any resource constraints, it is guaranteed to eventually be cheaper than bunker fuel. Again, you are repeating anti-wind and anti-solar argument the past. If those technologies plunged to nearly nothing in cost, why would the next renewable technology that relies on an extremely plentiful substance be any different?

Finally, you're entering into the "I'm just making this shit up" phase of your argument. People have already made ships to run on hydrogen. Something similar has happened with a variety of other green fuels like methanol, ammonia, etc. None of this is even that challenging of a problem. The only thing that is proving to be hard is trying to power everything with a battery. It is totally nuts for ships, and that's even before realizing how much it costs.

FYI, nuclear has been killed off due to legislation, many due to fears over radioactive waste. But hydrogen and other chemical fuels have no such concerns. It will scale the same as wind and solar did.

> People have already made ships to run on hydrogen.

Only at a significant loss. You can go out and buy a hydrogen powered car today and pay more for the car, have worse range, pay more for energy to move that car, and have to deal with limited infrastructure. People are operating battery powered boats at a profit, that’s a monumental difference.

Limiting yourself to “free” for electricity means spending more money on equipment. Actually making industrial scale hydrogen requires expensive electrolysis equipment and having that sit idle 95% of the time is expensive independent of electricity costs. Similarly aiming for seasonal storage requires investment in storage so it’s there when you want it. This isn’t free and no you can’t just reuse natural gas systems, even just detecting small leaks requires different equipment, the demand is higher, hydrogen embrittlement is a serious problem, and the energy density is different.

You can consistently get ~3c/kWh for close to 8 hours a day via building your solar farm, but that means your electrolysis equipment is still idle 66% of the time and your still paying 3c/0.18 = 16.7c/kWh just for electricity ignoring other costs to get 1kWh of useful energy at the end.

This is why Hydrogen is currently expensive, until something fundamentally changes with the underlying economics due to new technology it’s going to stay expensive.

Nuclear has both economic and risk issue. Legislation impacted individual countries but a handful are built each year. It’s not even just disasters, several nuclear projects have gone wildly over budget scaring both small countries and free market investors. The risks are high even ignoring accidents and the rewards don’t match those risks.

Westinghouse top executives were convicted of fraud for over covering up project failures in two canceled South Carolina nuclear reactors: https://www.reuters.com/legal/government/ex-westinghouse-exe...

That’s part of a long list of failed US reactors and an even longer list globally some of which where even worse: https://en.wikipedia.org/wiki/Category:Cancelled_nuclear_pow...

That said, I acknowledge politics has played a role it’s simply not the most important one. Japan was happy with nuclear until an unexpected 500 dollar bill, other countries look at that and get concerned.

Because prototype vehicles are not supposed to be profit centers. The fact that now you are shifting to cars shows how uninterested you were in this topic to begin with.

Please stop making shit up. We already have seen people reuse or at least test natural gas infrastructure with hydrogen. There are no showstopper problems. It is a fully solvable problem and is going to happen.

You literally are making up your own fictional scenario to rationalize how you can disconnect $0.02/kWh electricity from cheap hydrogen. This is pure incoherent rubbish.

Ultimately, you are creating an alternative reality to rationalize your delusion that batteries can power anything while nothing else can. No fucking idea why are you ranting about nuclear safety either. It is one of the safest energy sources out there.

Cars are meaningful because they clearly demonstrate current Hydrogen pricing and technical issues.

Economics isn’t rubbish. Yes you can get X kWh at below Yc/kWh every month, *as long as you are willing to let equipment sit mostly idle. My point about 3c/kWh is simply the point where you can both operate equipment 1/3 of the time in most locations thus minimizing transmission issues, and you aren’t limited by the surplus of the local electricity grid. It’s simply a point of comparison. Sure, you can get

It’s also meaningful when including transportation and all other overhead bunker fuel gives you ~15c/kWh after you burn it, though this varies a lot. https://agtransport.usda.gov/Fuel/Daily-Bunker-Fuel-Prices/y...

Include overhead and green hydrogen generation is currently dramatically more expensive and it needs drastic efficiency gains to be viable. That’s simply the truth.

Your only input is your super cheap electricity and water. Your own logic dictates that hydrogen must be cheap. Scaling up is the only thing that has to happen.

You should stop doing logical backflips and making nonsensical comparisons.

> Because prototype vehicles are not supposed to be profit centers.

Hydrogen systems still being classified as prototypes after decades of research should tell you something. Nobody is making hydrogen boats because they’re simply inferior in just about every conceivable way. Cars got heavily subsidized, billions in R&D over decades, and are a failure. Hydrogen boats aren’t even vaguely worth trying to bring to market.

Economics uncovers bullshit, you can’t hand wave away the cost of infrastructure, someone needs to pay to create and maintain it. Solar can hit 2c/kWh for a few hours per day in a few areas of the globe, but now you’re both idling infrastructure and stuck with long distance transportation of Hydrogen and or electricity which has their own associated costs. Just do X sounds great, but doing X always has associated costs.

For comparison, including transportation and all other overhead bunker fuel gives you ~15c/kWh after you burn it, though this varies a lot. It’s horrifyingly polluting, but dirt cheap.

Scale alone isn’t going to fix green hydrogen it requires a fundamental breakthrough.

And BEVs are well over a hundred years old. You are so fucking dishonest, it's seriously painful talking to you. You didn't even register the part where I said hydrogen boats already exist. You aren't even trying to have a conversation about green shipping. It's all just about more BEV marketing from you. Everything you say can be a lie to further this goal.

Seriously, who do you work for? I can't imagine you not having an agenda here.

If the efficiency of propane production (from atmospheric CO2) can be made even close to that for hydrogen from hydrolysis, then the systems benefits of propane over compressed and/or liquid hydrogen will blow liquid hydrogen out of the water. Hydrogen is an awful fuel. It's only real advantage is the potential for being carbon neutral, and the fact that it doesn't create noxious air pollution when used in a fuel cell. It's claimed advantage of energy density is at best a wash in most applications - higher density by mass, but much lower by volume. But everything to do with hydrogen as a fuel system is hard, complicated, and expensive, compared to the alternatives.

What's your point? I literally said "renewable hydrocarbons will be a better alternative".

I'm saying that hydrogen is a bad option, but if e.g. this renewable propane turns out to cost $1000/litre then hydrogen wins by default. It wouldn't be that surprising, current synthfuel is expensive AF. And this new headline hasn't been commercialized yet, so it might not be viable after all.

The benefit of hydrogen fuel is that, while it works poorly, it does work and is already in use today, in e.g. forklifts. It was in use decades ago, in fact. It's boring and low-risk, if we can't find anything good.

Storing propane is much easier than storing hydrogen. It liquifes at reasonable pressure so it can be stored as a liquid in uninsulated, relatively lightweight tanks (the tank under your BBQ grill is an example).

Hydrogen leaks out of almost everything, embrittles steel, is hard to store as a liquid and needs very high pressures to store a meaningful amount as a gas.

Renewable propane would be great, better than hydrogen fuel, but it doesn't exist yet. It might never pan out.

If the carbo is being extracted from the atmosphere, does it really matter it gets rereleased? It would still be net-zero.

Might be better of extracting the carbon and just storing it, rather than releasing it again.

Net-zero is nice, but extraction and storage is net-negative.

By the time any of this hits a reasonable scale we'll be past a reasonable CO2 level in the atmosphere. The best thing to do may well be to use it as plastic feedstock and just chuck it into landfill.

> Are there use cases where we must burn propane because we can’t replace that process with electricity?

That's not relevant in the short term. There are so many things using propane right now and it's a lot easier send them "renewable propane" than to entirely retrofit them to be electric.

Not if it’s a lot more expensive.

You can run ICE cars on LPG (propane + butane, would probably work on pure propane as well), with minor (<1000$) modification in the fuel injection system and fitting a proper tank.

This could make millions of older cars cleaner, also in the developing world. LPG is already cleaner, would benefit the developing world, and ICE engines can be produced without needing exotic materials, can be recycled 100% by smelting, are a proven, well known, durable technology, unlike lithium batteries (which are also proven, but recycling and exotic materials are problematic), and are and will be a popular technology in the developing world for a long time.

Also it would allow for cheaper and cleaner cars in the developed world, where not everybody can afford the electric dream many here are living.

It would also be somewhat suitable for long haul and heavy machinery, but most likely in a hybrid drivertrain setup.

Also it would solve the big issue of the German home heating and industry: how to stove away the sun and wind from the summer to the winter, when in the windless dark days nowadays coal is burnt, as battery of hydro storage cannot be scaled beyond a few days capacity at extremes.

There is already built, or cheap technology to gas powered solutions, no need to transition to new technology hastily. This would give runway to the green transition, as it could be net zero carbon footprint solution with less disturbance to the existing solutions.

This. There's no way the global car fleet is switching over to electric any time soon. Globally there are around 1.2 billion cars, with 65 million or so sold each year, which puts us at 15-20 years for the fleet to be replaced if every single car sold from today were electric.

Like it or not, internal combustion cars have many advantages, a big one being that they can run on different fuels. Converting to green LPG or (my pick) methanol will have to happen if we're serious about reducing transport emissions, because it's the only immediate non-cost-prohibitive option.

What about cooling? As engines get smaller they quite often will dump in extra fuel under load to ensure the cylinder doesn't melt.

E85 does that even better, as the cost of being less dense. But it cools so much better you can run higher boost.

What about LPG?

And if we want LPG to be something we still have to deal with legislation, like in many countries you can't park in an underground garage with LPG.

> will dump in extra fuel under load to ensure the cylinder doesn't melt

They dump extra fuel to prevent knock. It's hard to melt cylinders.

> can't park in an underground garage with LPG

And yet people park. I haven't heard about an accident in the last 5 years. Maybe it could be managed by an extra detector?

LPG engines could be excellent generators (back ups or range extenders for cars and trucks). The emit less particulate matter and NOx.

I'm not a mechanical engineer, but for one I have driven my father's LPG-converted car, and the cylinder didn't melt so far, so I think this is already more-or-less under control. Many car vendors in the EU (especially south and east) offered LPG-petrol bi-fuel powered cars out of the box. (I know of Dacia and Fiat for sure, and according to my brother LPG converted hybrid Priuses are popular in Poland for insanely cheap operations by cab drivers for example).

For engines getting smaller: the LPG operation of petrol engines provides lower power output (and lower torque), so an uptick in LPG powered (dual fuel?) cars would probably mandate slightly different engines sensible (bigger ones), the market would surely adapt to it.

E85 would also be fine if it wouldn't be manufactured from intensively farmed monocultural agricultural products, which make it totally non-sustainable and non-renewable factoring in the sustainability problems of industrial agriculture (soil erosion, carbon depletion of soil, death of soil microbiome, groundwater depletion, etc)

The parking ban for LPG in closed garages is a real problem, I have faced it myself. Though it is justifiable, but then it would also be justified for the BEVs as there were cases already where (heat from) a battery fire compromised the structural integrity parking complexes, so it is a manageable risk probably, and probably mostly legislative.

> in many countries you can't park in an underground garage with LPG

I'm not sure why parking with LPG is a problem but parking with 10-20 gallons of gasoline is not?

LPG is a gas, and it is heavier than air.

In case of a leak there is a risk in case of a not-ventilated enough underground garage it is possible that the gas accumulates in the lower parts before it can be sensed/sniffed, and a mix of just 2.1% with air is already at risk of explosion if a spark is generated.

Security norms changed in the EU around 2001, the norm is the ECE/ONU 67-01 (though different countries may have implemented differently in the local Law) and LPG powered cars conforming to that standard are allowed (generally) to be parked in underground garages BUT only on the first underground floor and only if the garage is conforming to some (earlier) ventilation standards.

AFAIK cases of explosions/fires related to LPG car tanks are extremely rare (thanks also to the added safety measures mandated by ECE/ONU 67-01), whilst fires/explosions originated by domestic LPG use, while not common, are more common than what they should be (the tanks in themselves are generally safe, but the - often underground - pipings often are not).

Gasoline vapors are also heavier than air, and its lower explosive limit is only 1.4%. If my parked car leaks 10 gallons of gasoline is that really any different? Or are LPG tanks more prone to leaking? I would think not, because they are probably heavier steel not the 18 gauge sheet metal (or plastic) of an automobile gas tank. But if the rule is there, I guess it must be. Hard for me to see the rationale though.

Yeah, but that solution means your gallon of gas, or its propane equivalent, costs 45$.

Electricity is way cheaper at the poont of generation than for residential consumer.

IIRC, solar now gets to about 3$ per Mwth, so purely energy cost would be about 0.33$ per kg of propane if 100Mj of input energy per kg of propane stands for that electrolyser plus stated 13Mj for Co2 capture for 1 kg of propane. So, the cost is not negligible, but could be competetive even now, and solar is likely to get cheaper.

How are you arriving at this number?

No matter how expensive it is, on a short enough timescale it is always going to be cheaper to use "renewable" propane over retrofitting to be electric.

> There are so many things using propane right now and it's a lot easier send them "renewable propane" than to entirely retrofit them to be electric.

I see statements like this every now and then, and I really wonder where that comes from, because that is not at all obvious, and most likely in most cases wrong.

If you imagine that "renewable propane" is something that you can just get, then it may appear easier to use your existing devices. But it's not. It's something that is not produced at any meaningful scale anywhere. There are no industrial processes to do so yet. You're talking about creating a whole new industry using technologies that don't exist yet, and by the way, a new industry that needs massive amounts of renewable energy. A lot more of that renewable energy compared to direct electrification. Nothing about that is easy.

What? This is a thread about a new technology that is a proposed commercializable "renewable propane" generator.

This whole conversation is a hypothetical. Restricting the discussion to only existing technology makes no sense.

I haven't said you can't discuss them, I was pushing back against the idea that this is easy.

They didn’t say that it was easier, but that it was easier than changing everything to run from electricity, which is true.

> It's something that is not produced at any meaningful scale anywhere. There are no industrial processes to do so yet.

As opposed to...replacing every single ICE with an all-electric equivalent. I think scaled up renewable propane would be a much cheaper cost overall than rebuilding every single vehicle in existence.

> I think scaled up renewable propane would be a much cheaper cost overall than rebuilding every single vehicle in existence.

I don't think you have any realistic idea about the energy costs of synthetic hydrocarbons. We're talking about something in the range of 5x the amount of energy you need. Think 5x the number of wind turbines and solar panels, and then reconsider if you still imagine that is a cheap solution.

> Are there use cases where we must burn propane because we can’t replace that process with electricity?

I think this might slot in everwhere we currently plan to use hydrogen, with the added benefit of larger storage.

Here in Europe we have massive natural gas storage facilities so we can buy gas during summer to use for heating in winter. We will need something similar but renewable. If we can fill that storage with green propane, that would be amazing. It would mean we can keep our heating infrastructure. And we have an amazing use for the solar over-production in summer.

Honestly tho, this sounds to good to be true.

> this sounds to good to be true.

This post seems to have gotten a lukewarm reception. People are maybe extra sceptical after the lk99 dud.

it’s probably still more efficient to burn the gas in power plants and use heat pumps for heating.

Also saves us from maintaining a residential gas network.

Maybe, but if everyone starts using heat pumps we have a problem in getting enough copper in the ground everywhere on time. So even if it's temporary (20 years or so) this is still a great solution.

The copper is mostly already in the ground. At least in the Netherlands it is.

Apparently decades ago some absolute madman genius decided that we should put down 5 copper cables to every house and building for 3-phase power, even though they only needed one phase for the coming decades.

You know. just in case.

> Maybe, but if everyone starts using heat pumps we have a problem in getting enough copper in the ground everywhere on time.

In New Zealand everyone uses heatpumps and there is no problem with everyone running them. Heatpumps don't use a huge amount of power even on cold days. If the grid can handle everyone cooking dinner at 6pm, it can handle heatpumps running throughout the day keeping the house warm.

Fast electric car charging on the other hand draws a lot of current.

At energy level a heat pump never made sense, it merits are with the fossil fuel transition.

Example, a gas furnace runs at 100% efficiency (103% I believe). Heat pump at 300%. Gas to electricity to home goes at 30%. End to end they both perform at 100%. So on efficiency perspective the gas furnace equals the heat pump - but at a much lower cost.

Retaining the gas network saves us from the massive investments needed in the electricity network.

This calculus changes if you consider that on most winter days, a big part of the electricity will come from wind instead of synthetic gas.

No, your point was on using propane gas to produce electricity for heating. If your consider/complicate the equation with other energy sources (coal, wind, ...) the outcome is more random.

Heat pumps do not make sense unless the energy transition into the equation (wind and solar indeed). But also then, there are major shortcomings with wind/solar currently not yet fixed. For example, my home produces appr. 12 MWh solar energy per year and the heat pumps use a similar amount. Nice balance, but too bad the is a gap of six months between the two.

A gas furnace isn't 100% either (103% is impossible, they lie about what 100% means), and gas to electric can go up to 60%. Heat pumps can also go over 300%, so it's definitely possible for a heat pump to beat a gas furnace.

About the gas furnaces, their efficiency exceeds 100% because of water vapour condensation. It happens both in the furnace and in the plastic exhaust pipe that exchanges heat with the outside air inflow. Gas comes in, liquid goes out and your law of thermodynamics is preserved. AFAIK the majority of housing is using this.

It would surprise me if gas turbines exceed 40% on average, and then the electricity still needs to be distributed. New turbines, probably particularly when using propane could do much better indeed.

My heat pumps all advertise a SCOP of around 5 for heating, and I guess the domestic hot water it would be 2.5 (don't have that, using solar for that myself). And there is a lot the installers can and will screw up, just read some user forums on this. And which consumer actually checks the real COP? So large numbers of heat pumps will perform far from optimal without somebody noticing. The 'screw up surface' of gas furnaces is much smaller. For example, ground heat sources rarely get replenished in summer (not mandatory for residential in my country).

Yes, heat pumps are more efficient. But they require lots more infrastructure.

Not only is that going to be expensive and thus impopular. It will also be a delayed transition, and use up an incredible amount of resources.

Not that we should do this instead of heat-pumps. We can do both. Heat-pumps in new houses and if possible when replacing old furnaces.

For all the existing stuff, this could be a great stop-gap.

I don’t disagree

> But they require lots more infrastructure

Trenched gas lines require extensive infrastructure; while each point of use also has electrical service. How is gas less infrastructure?

CO2 concentration in atmosphere is .04% not .4% But Yes is too low as a source for this process.

Estimates I found (in one article, I linked it somewhere else) put the energy usage of CO2 capture from ambient air at about 2800kwh per ton of CO2, someone else calculated one ton of CO2 would produce 376kg of propane. Which is about 5254 kwh. So it would be a significant hit to efficiency, changing it from about 90% to 60%. But that doesn't bring the efficiency to stupidly low levels.

So lets pump more CO2 into the atmosphere.

> .04%, not .4%

Give it time, we're working on it...

> Concentrations of CO2 in the atmosphere were as high as 4,000 ppm during the Cambrian period about 500 million years ago, and as low as 180 ppm during the Quaternary glaciation of the last two million years.

So a range of 0.018% to 0.4% over the last 500 million years. We’re currently at ~420ppm, and human impact is estimated to have been about +140ppm since the 1700s where we had been at 280ppm for the ~10,000 years prior.

If the planet ever hit 0.4% again it would be due to natural not anthropogenic reasons.

> Are there use cases where we must burn propane because we can’t replace that process with electricity?

"Must", no. But hundreds millions of cars and trucks on the road right now can be converted to propane. It's relatively easy and well understood and you keep your same motor and drivetrain.

Converting existing cars and trucks to electric is so intensive it's almost unthinkable ... cost, energy input, waste, etc.

That process relies on DAC, plus electrolysing H2 and that conversion processes, which means the propane would have to be at the equivalent of 15-45$ per gallon. What is less affordable?

The current iteration does. Research often brings costs down, though there is no guarantee.

It's a matter of time scales. If every car sold today were electric, it would still take 15-20 years for us to completely replace the fleet. Remember, there are a good 1.2 billion or so cars, and around 65-70 million are sold a year.

If the cost of this technology could be brought down within a decade, it would be a way of reducing emissions for the large chunk of the fleet that isn't electric, in a cost effective manner.

The other, more pragmatic, answer is that internal combustion engines aren't going anywhere. They have too many advantages over their competitors to ever fully go away, so we need cost effective ways of running them that are also carbon neutral or negative. Some of the links in this chain, like low cost electrolysis, are vital for other reasons (e.g. the food we grow uses fertilizer made from hydrogen split from fossil fuels. We need the fertilizer or the planet starves, and we need a source of hydrogen that doesn't also produce 11 tonnes of CO2 for every tonne of hydrogen produced).

It's funny to see people suddenly say this is doable, even though many posters in the past have claimed that it is totally impossible.

The problem ultimately is that CO₂ capture from the air is another expense that has to be paid, both in terms of cost and energy. Sure, if the entire process becomes so cheap and widely available that this no longer becomes issue, then we can certainly do it. But until then, it is a major stumbling block.

The other problem is that if all you want is something more "practical" than hydrogen, you will stop at methane. Same basic idea as this, but you only need the Sabatier process. And we already have many facilities capable of dealing with methane. So we do not necessarily need to go further. But if you insist on long carbon chains, why stop at C3? Keep going until you reach C8, or even C12-20, at which point you have the equivalent of gasoline or diesel. Basically, get to the point where you have a liquid at room temperature, and it will be even more practical than propane.

> The problem ultimately is that CO₂ capture from the air is another expense that has to be paid, both in terms of cost and energy. Sure, if the entire process becomes so cheap and widely available that this no longer becomes issue, then we can certainly do it. But until then, it is a major stumbling block.

That is, of course, very true. Per calculations upthread, the energy cost of DAC isn't that huge, but indeed it's for the time being a very immature technology that hasn't been demonstrated at scale.

> The other problem is that if all you want is something more "practical" than hydrogen, you will stop at methane. Same basic idea as this, but you only need the Sabatier process. And we already have many facilities capable of dealing with methane. So we do not necessarily need to go further.

In principle yes. I guess it's a question of cost. Is the cost of an H2 electrolyzer + the Sabatier reactors etc. lower than this propane electrylyzer? If this propane electrylyzer thing could be done cheaply, that could be the gamechanger. Not the fact that it's technically possible to manufacture synthetic hydrocarbons, we have multiple ways of doing that, though all of them tend to be both expensive in terms of capital cost and somewhat inefficient.

> But if you insist on long carbon chains, why stop at C3? Keep going until you reach C8, or even C12-20, at which point you have the equivalent of gasoline or diesel. Basically, get to the point where you have a liquid at room temperature, and it will be even more practical than propane.

Indeed, from a handling and transportation point of view, the longer hydrocarbons are pretty much optimal. But like above, it's a question of cost. Fischer-Tropsch installations tend to be very capital intensive, yield is an issue etc.

So if this propane electrolyzer turns out to be industrially feasible at a low enough cost, maybe it's overall more efficient to deal with pressurized storage systems.

> Per calculations upthread, the energy cost of DAC isn't that huge

All I’ve seen so far are speculations based on a small prototype in Iceland that is still very expensive and has access to free energy. I’ve had to add up the costs that you list myself (you are not giving any numbers), and it ends up being a prohibitively expensive gallon of fuel—an order of magnitude more expensive than it is now. How is that reasonable when most states would lose their head with a 10% increase?

My concern is that most of the time, the math goes: “Let’s assume electricity is free, and people somehow still want to drive an ICE.” and conclude with, “We just have to continue subsidizing a pathologically dangerous pollution by 90%.” hoping to capitalize on the heads of states fear of a revolution.

I can see why that looks tempting to people who refuse to admit that we must shift away from fossil fuels and latch on to plans to paint their industrial assets as renewable. Still, it ends up being an inefficient Rube-Goldberg machine, where adding solar panels on the roof of wherever you need energy works. I’m all for failing convincingly, but you must admit when it’s not working.

I’ve heard that mining equipment was too large and could never be electrified… Those converted the fastest (custom engines, high torque, regenerative power, far away from fuel supply but sunny/windy location) and with glee (lower maintenance when technicians have to fly in by helicopter). Prototype boats and airplanes can work “indefinitely” because solar panels can generate enough energy for them to work 24/7.

I’ve yet to hear about a single industrial process that needs carbon-chain fuel to work.

Whatever happened to a similar announcement from Stanford in 2019?[1]

[1] https://news.stanford.edu/2019/10/17/new-catalyst-helps-turn...

https://en.m.wikipedia.org/wiki/Abundance_of_elements_in_Ear...

Ruthenium and Iridium are known stable catalysts that are also among the most rare elements. Their structure used Ru. This new paper seems to propose only abundant materials. If it can be used at scale and proves to be stable that would be an important advancement.

I wonder can they use the same membrane/catalyst for the inverse process: oxidize propane with atmospheric oxygen, release water and CO2, and instead of heat directly produce electricity without too much energy wasted in the process?

If yes, the consequences for energy storage might be significant. The energy density of propane is 49.6 MJ/kg. Apparently, Li-Ion batteries are about 0.8 MJ/kg, more than 50x the difference.

If it is possible, this would make off-grid living nearly trivial (from my perspective in the US Southwest). Solar panels to generate electricity, this system to create propane or electricity, and a large off-the shelf propane tank for cloudy days (or weeks!).

> and a large off-the shelf propane tank for cloudy days (or weeks!)

Months. I have a residential sized propane tank for gas and backup power that only gets refilled once a year at most. Worst case scenario I can go off grid for two to three months in the summer on a generator (tested frequently) and this is a pretty standard size for exurban houses in California.

> I have a residential sized propane tank for gas

Could you elaborate on that? I imagine most people do not have any concept of that. Are you talking basketball, person, tiny car, SUV, or something else in terms of size? I'm imagining something between tiny car and SUV.

https://www.amerigas.com/about-propane/propane-tank-sizes I've most commonly seen the 120 gallon size at homes that use it for a water heater.

Propane fuel cells have been around for a while: https://www.wattfuelcell.com/portable-power/watt-imperium/

Do you know how much WATT Imperium costs? No information on their web site.

AFAIK both fuel cells like that, and the inverse carbon capture machines, are technically possible for decades now. The issue is high cost due to precious metals in the catalyst.

Apparently, these guys have solved the issue with much cheaper stuff for the catalyst, molybdenum phosphide.

Electrolyzer reactions tend to be reversible...

If they could do the reverse (water+propane to CO2+hydrogen+electricity) at the efficiency claimed (91%), they can replace all gas turbine generators (who typically have efficiencies of only 60% at best)

Reversed electrolyzer would be called a fuel cell then? What are their typical efficiencies?

Yep. Fuel cell efficiency varies widely, but the efficiency of the reverse process is a good guide - typically efficiency is fairly symmetrical.

Gas turbines scale much better than fuel cells, and can achieve great power density, are durable, can be produced without too much exotic materials needed, are a proven technology. If you can solve the storage of intermittent renewable production as conversion to propane, you already won!

At a current density of 395mA/cm² @0.8V, these already won on the power density and scalability front.

500 stacked 0.5mm layers of this would make 400 volts for an ev battery or stationary AC generator. It would have a power density of 6.3 kilowatts per litre, far exceeding both lithium batteries and gas turbines.

Did they? Are they capable to be scaled to 100 MW scales with MTBF of years already?

Propane fuel cells already exist, and are in use for remote power. The problem with using them for cars is that they operate at high temperature, so you spend a lot of battery warming the cell for steady state, but most trips are short so you would be there before it got to temp. Might make sense as a phev sort of thing where you punch in a trip and it decides to warm it up or not. You'd always leave enough battery to warm the cell while driving so you never get stuck.

High temperature isn't a problem for cars. It's simple enough to have a small fuel cell which can be heated up quickly, which in turn can provide the energy required to heat up a larger cell if needed. A small battery can drive you a few miles while that process is happening. The small fuel cell could then recharge the battery while parked if most journeys are only a couple of miles, avoiding the energy cost of heating the large cell except for extended journeys.

Not sure why no one has done it? Not carbon neutral I guess, but paired with this and solar power it would be. Batteries are already so good is probably part of it too. But adding about 25% travel time on long drives is annoying.

Up until this point I'd imagine there was no significant advantage to creating propane vehicles unless they could be made significantly more efficient than petrol or diesel (which I'm guessing is not known to be the case)

by comparison, this discovery could make it a green-vs-brown fuel debate, at which point it would be much more valuable to invest in for vehicles

Propane combustion vehicles are common, and I'd guess a fuel cell would extract roughly 30% extra energy from the same fuel. They typically have battery efficiencies.

This is massively more complex then you make it sound. And if it doesnt work at least as well as current ICE its not going be used. There is a reason this simply isnt done.

If you want to use that fuel, just burn it.

Several tesla superchargers near where I live have fuel cell setups, presumably to shave peak loads for the rare cases that the charging stations are all in use and all charging at peak rates.

I suspect they have batteries rather than fuel cells?

Tesla is known to colocate them for exactly the reasons you say - also to shift load to cheaper hours of the day and to get paid by the grid for balancing services.

I think the current ones don't use generators, but that one time they used a gas generator to charge Teslas, called it a "battery swap station", and got a bunch of money from California that was supposed to go to zero-emissions car projects. I doubt they'll ever live that down.

Live what down? California paid for a research and demonstration project. Tesla did that but decide for a whole number of reasons that it wasn't worth doing.

sorry for the late reply -- definitely fuel cell setups.

Orleans MA and Hyannis MA supercharger stations. The one in Hyannis is right next to the superchargers, the other is 2 minutes walk away.

I believe one or both have "bloom energy" branding.

I can't find a good picture on the internet.

I wonder if you can have the same plant act as both a propane producer at times of extra power available on the grid, but also generate electricity when there is a shortage. Then the power density and exotic materials are irrelevant as the plant already exists.

You'd use the plant mainly to make propane, just run it backwards when electricity prices were the highest.

Shouldn’t the chemical reaction be: 4 H2O + 3 CO2 <=> C3H8 + 5 O2

The reaction described in the paper doesn't have spare oxygen on either side, presumably because oxygen has a habit of destroying catalysts and being explosive when mixed with hydrocarbons. Instead hydrogen is required.

So you would need to have two separate electrolyzing processes, one that isolates H2 and one that runs this operation? How much energy would have to go into the first one?

I’m asking because a lot of the demand for hydrocarbon that I see mentioned is for processes that have more efficient, non-hydrocarbon equivalents.

(Not having access to the paper)

So are you saying the reaction is

10 H2 + 3 CO2 <=> C3H8 + 6 H2O

Of course, neither this nor the reaction mentioned in the parent comment matches up with the diagram in the linked article which says "water + CO2 => propane + water", which well, doesn't make sense..

actual paper: https://www.nature.com/articles/s41560-023-01314-8

The press in my corner of the world is going to have a field day with this, considering that over 13% of passenger cars around here are dual-fueled with petrol and LPG (so mostly propane) - they put it even in hybrids.

Hilariously enough even at this rate of adoption few underground garages allow entry for such vehicles.

I suppose it won't see adoption in cars anytime soon because looking at electricity prices it can't hope to be less expensive than fossil fuels.

Probably the best time to be a propane and propane accesories salesperson.

Good for Strickland Propane for sure

I tell ya hwuhat that right there is a CLEAN BURN.

FYI, there’s a startup doing CO2 → Methane conversion called Terraform Industries.

https://terraformindustries.com/

I asked the cofounder of his thoughts here:

https://twitter.com/ccorcos/status/1694021803654693342

We can add another company in the sector to the bunch:

https://www.prometheusfuels.com/news/dude-wheres-my-fuel

I am curious how do they compare

> 1-ethyl-3-methylimidazolium-functionalized Mo3P nanoparticles coated with an anion-exchange ionomer

How hard/expensive are all their materials to produce at scale?

Molybdenum is not as rare and expensive as platinum, so that’s certainly a win.

1-ethyl-3-methylimidazolium is a fairly simple molecule and already used in industry.

Stupid question, if we find a commercially viable way of converting CO2 into fuel is there a danger of "global cooling" because people will get too greedy with this?

Only if more fuel is created than is used, which would seem to be a waste of energy. On the whole, it should be a balanced loop and should net off.

Burning the propane will release the same amount of Co2 again... So I doubt it will change much

Theoretically it would be possible, but we would just release some carbon from other sources, there's a lot of it in various rocks if fossil fuels somehow expired (we still have a lot of those).

- CO2 isn't the only greenhouse gas.

- This process produces hydrocarbon fuel. It will be burned and the carbon will return to the atmosphere.

I suppose propane could become a chemical feedstock. Then the carbon could theoretically be tied up for a while.

Even if it winds up back in the atmosphere, it's displaced an equivalent amount of new CO2 going into the atmosphere.

Pulling enough CO2 to make a kilogram of propane and then burning that kilogram of propane for electricity is still better than burning a kilogram of freshly fracked propane.

One offsets consumption. One just adds consumption.

Only if your source of electric doesn't add CO2. If you burn coal to make propane you are worse off CO2 wise than using regular propane. We have a lot of wind and solar, but most places they are still a minor part of the electric mix (if this applies to you, it wouldn't be hard to get a lot more wind/solar in your grid).

No: the atmospheric CO2 is at the bottom of the energy hill. In order to turn it in to fuel you need to pump in all the energy originally extracted from the fuel, then some more.

After you've re-expended the entire 20th century's worth of fossil fuels energy equivalent in sucking CO2 out of the atmosphere, not burned it, and stored it in a country-sized propane tank, then maybe we're back to 19th-century temperatures.

The earth is not a zero sum game, we get energy from the sun. Photosynthesis reverses the process turning co2 into sugar and o2.

And? So?

That means co2 is not the bottom of the energy hill.

In the photosynthesis case the bottom of the energy hill is helium in the sun’s core.

Well and also the CO2 isn't acting as a fuel, it acts as a battery or resource.

Plants make sugar from CO2, and also burn that sugar back to CO2 (plants respire overnight - they're not pure CO2 consumption machines).

"Bottom of the energy hill" is a chemist's short hand way of saying that we can't practically extract energy from CO2 reacting with anything useful, meaning chemically this is at the bottom end of reactions that happen without energy input. To convert it into something reactive, you need to invest energy to split it up again into its constituent parts, which is what happens during photosynthesis.

"Bottom of the energy hill" is a useful term in a lab. However the earth is not a chemistry lab. We cannot ignore photosynthesis outside of a lab as it is a factor that exists.

> We cannot ignore photosynthesis outside of a lab as it is a factor that exists.

I apologize if this wasn't clear. It's an expression about energy potentials, and as such it's not just useful in a lab, it's an essential piece of information about the substance.

For example in the original context of this comment thread, a person asked whether there was a danger of people exhausting our atmospheric CO2 because they got too greedy with this technology - a question that can in fact not be answered meaningfully without talking about energy deltas. The fact that CO2 cannot be practically processed in a way that releases energy is the only pertinent information when talking about this.

That would be an easy problem to solve. We are very good at heating up the atmosphere.

More CO2 should also stimulate plant growth, CO2 is a bit of a limiting factor there.

Yes, and before humans the earth was on a cooling trend, though only measurable on a geological time scale (millions of years). A little plant matter gets converted to charcoal and then coal every years. Though biology mostly trys to get at that carbon first.

The application of this is not in energy production or - realistically - CO2 capture on a global scale. This takes huge amounts of energy to do and requires a sophisticated chemical synthesis in the background in order to replenish the catalyst.

Pretty much the only reason to do this would be because you're specifically interested in generating propane. For example, it could be very useful for ISRU on other planets, or to generate propane "for free" from a solar setup.

If your goal is energy production, you'd just use the output of solar panels directly without this costly step in the middle. If you want to store energy locally, electrolyzing water into H and O would be hugely more cost effective. But propane is a more dense fuel that would be useful for mobile applications such as ships and cars, and can also be used as a raw material in chemical synthesis.

Taking the carbon from the atmosphere will always be more expensive than from some carbon-rich rocks that form a huge fraction of the Earth's crust.

In fact, our most effective ways to take carbon out of the atmosphere today all involve a step of letting some mineral turn into one of this carbon-rich ones, and extracting it from there.

It'll always be more expensive to extract carbon from the atmosphere, but if it produces a valuable byproduct and the power to run the process is very cheap (excess solar) it might still pencil out.

I fail to see anything that doesn't apply equally to the rocks.

When you have surplus photovoltaic capacity — an increasingly common situation — you could turn it to electrolysis. You still have to pay for the equipment, but it sounds like it could be pretty cheap.

It would cut out the cost of mining, and possibly a lot of transportation costs, if you can use the products nearby.

Doing quick napkin math it looks like to process a ton of CO2 it will require 1.6kW of energy, burning that amount of propane generates at 50% power plan efficiency you get ~3kW of energy generation...

8CO2+24H2O+24e→3C3H8+16O2.

Moles of CO2=1000×1000/44.01≈22726moles.

Total moles of electrons= 24/8×22726≈68178moles.

Total charge=68178×96485≈6.58×10^9C.

E=Q×V=6.58×10^9×0.8≈5.27×10^9J.

E_actual=5.27×10^9/0.91≈5.79×10^9J.

E_actual=5.79×10^9/3.6×10^6≈1608kWh.

----------------------------------

Moles of propane= 3/8×22726≈8522moles.

Mass of propane=8522×44.1≈375,670g≈376kg.

Total energy content=376×50.35≈18,932MJ.

Usable energy= 10,791/3.6≈2,997kWh.

Burning the propane takes you back to CO2, which you then turn back into propane again and repeat? If your napkin maths is correct, and the process is net energy positive, doesn't this violate the principle of conservation of energy?

It must take at least as much energy to turn carbon dioxide into propane as you generate when you burn that propane to generate carbon dioxide.

Isn't the input electrical energy and the output of burning the propane heat? If you convert the heat back to electrical energy, you get much less than you input into the reaction.

> If your napkin maths is correct, and the process is net energy positive, doesn't this violate the principle of conservation of energy?

In theory, yes, but you need to take into account all the energy that goes into the process, which includes the catalyst, and also the actual capture of the CO2.

The way i read it, this is "just" a way of turning already captured CO2 into fuel again in an efficient way.

Still, it does seem a little bit too good that you can obtain 3 kWh of energy by spending 1.6 kWh, but i guess time will tell.

This is just an educated guess, but . . .

Burning propane produces CO2 AND water. I think the missing bit is the energy required to split the water into hydrogen and oxygen before the hydrogen is used as an input to produce the propane.

Heat pumps can create 3 - 5kWh of heat from 1kWh of electrical energy.

Correction: heat pumps pump heat from 1 place to another. As in: place where it gets pumped out of, gets colder.

Fundamentally different process from exothermal chemical reaction, or electric heating using resistive wire.

Heat pumps do not create heat, they simply move heat from one place to another, which is an entirely different beast.

Using a traditional resistive heater, you're roughly creating 1 kWh of heat by spending 1 kWh of electricity (there is some loss), but with a heat pump you're moving heat, which is also why heat pumps become much less efficient the colder the temperature as there is less heat to move, and many residential heat pumps include a regular resistive heating element as a backup.

There's a great explanatory video on how heat pumps work here : https://www.youtube.com/watch?v=7J52mDjZzto&pp=ygUgdGVjaG5vb...

Good point, thanks for the correction.

My napkin says you have 8C on the left and 9C on the right, so your stoichiometry is off. I haven’t tried to check any of the rest.

I’m guessing the major error is that the -0.8V is “versus reversible hydrogen electrode ”, so it’s a half-reaction and you need to fill in the correct other half reaction, and there is probably H2 involved. Then you would dig out some free energy values to see how efficient it is.

(I only read the abstract.)

Thx for the catch!

Fixed the math using chat gpt :P.

Reaction: 3CO2 + 12H2 -> C3H8 + 6O2

Number of moles of electrons (n): n = 3 * 4 = 12

Total charge (Q) in Coulombs: Q = (-395 * 1 * 100 * 3600 * 0.91 / 1000) * 12 * 96485

Voltage (V): V = -0.8

Total energy for given current density: E = Q * V

Moles of CO2 in 1 ton: n_CO2 = (1000 * 1000) / 44.01

Total charge for 1 ton of CO2: Q_total = (12 / 3) * n_CO2 * 96485

Adjusted charge considering Faradaic efficiency: Q_adjusted = Q_total * 0.91

Total energy for 1 ton of CO2: E_total = Q_adjusted * V

Convert to kWh: E_kWh = E_total * 2.778e-7 E_kWh ≈ 17707.4 kWh

https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085...

Gives a specific CO2 emission for propane of 13.8 kg carbon / kWh fuel, so your numbers are at least vaguely credible. But your reaction is devoid of CO2, so talking about tons of CO2 is still odd.

> 3CO2 + 12H2 -> C3H8 + 6O2

6 O on the left, 12 on the right.

24 H on the left, 8 on the right.

That is when using propane for electricity.

I think there is a lot more value in burning propane for heating houses. Especially in places (like Europe where I live) that are already build to use gas for heating.

Especially if you consider the massive gas-storage facilities that are common here. We have 12 billion cubic meters of gas-storage here in the Netherlands, on a yearly consumption of 40 billion. That means we could use 'green propane' to load-shift about 30% of our heating from winter to summer. That would be amazing.

And if you sneeze at propane it becomes liquid (-42C). Not sure how natural gas is stored though.

Heating use is indeed very obvious, and so is transportation use. Many countries have an elaborate distribution network for LPG and fitting a car to run on LPG is also very easy.

BTW, hot air balloons also run on propane.

> Not sure how natural gas is stored though.

Mostly stored underground, but it's also shipped and stored in a liquefied state at -162C. Propane is one of the components of natural gas, so I would think any facility that is able to store natural gas should be able to store propane easily.

According to this article: https://www.rechargenews.com/energy-transition/the-amount-of...

The cost of carbon capture straight from the air is about 10GJ per Tonne (they quote 8.8 and 14 from competing sources). Which is about 2800 kWh That would put a serious damper on the efficiency, but might make it viable even when 'easy' sources of CO2 (like the exhaust of fossil power plants) are no longer available.

Please don't refer to power as energy or use units of power when you really mean energy, it is bad enough when this happens in more traditional media.

It's a great idea for places like northern Canada where many technologies like solar don't work during a sunless winter. Wind is OK but it's complex to set up and maintain in such isolation. Diesel tends to be an easy solution but endless propane would be great if the regulator didn't freeze.

Propane also needs to be compressed from what I can see to about 200psi. Not a huge amount but it would take special equipment and power to run a pump.

Propane will turn to liquid before it reaches 200psi at normal temperatures. The exact pressure depends on temperature. This is basic chemistry, though probably a part you forgot about as it is simple and doesn't come up much '

From what I could find at 1 atmosphere propane is liquid but it has to be -42C. At 21C propane has to be at 850kPa (123 psi) to liquefy it.

Propane always struck me as a potential lower carbon aviation fuel since it easily liquifies under modest pressure, making the whole system lighter and more compact than natural gas or hydrogen.

Batteries would AFAIK need a 2-4X power/weight density improvement to do anything more than short haul electric flight. Short haul electric planes are possible today but not beyond a few hundred miles range.

So, we could take concentrated CO2 from a furnace, and instead of releasing it into the atmosphere directly, convert it to Methane, and then burn that incrementally?

Or could we possibly fit an exhaust-gas tank onto our engines that holds all the combustion products, and is collected and recycled at the gas station?

It's easy to capture at places that produce lots of CO2. Say fossil fuel electricity plants, and apparently also the production of Cement. Long term, these sources will hopefully dissapear. But short term, concentrated sources of CO2 are sadly still quite abundant.

It would be cool if, long term, the CO2 released by burning this in home furnaces for heating can mostly be re-captured.

>It's easy to capture at places that produce lots of CO2.

Not easy enough apparently, the US gov started subsidizing/taxcutting this because there was demand for CO2 in enhanced oil recovery but the price was too high.

This doesn't work. You need energy to convert CO2 back into propane. The CO2 is coming from fossil fuels, which you're still ultimately going to burn again to get energy back...putting the CO2 back into the atmosphere.

Only now you've thrown away some of the energy in losses doing the CO2 to propane conversion.

This would lower the efficiency of a fossil fuel powerplant, and this increase the CO2 emitted overall.

Only if you use energy from fossil fuels to do the conversion. Earth's energy isn't a zero sum game, we have plenty of decarbonized energy sources.

I meant to do the CO2 capture at gas furnaces in homes. Because the electric power available for heating is ofte limited, but might still be sufficient to gather CO2 from the exhaust of the furnace.

It'll cost energy, but it is a cheap source of CO2 for this electrolysis.

To convert CO2 back to propane you have to put in every bit of energy released when burning it and then some.

So again, it wouldn't work because as you note: the electric power available is less than the gas.

It would be great if natural gas is replaced with propane for households. Just imagine to fill up your ICE/LPG car at home, and to have a real wok burner without the need to change gas tanks.

For most home applications all your need is to replace the jets in the appliance - $.25 in parts. Stoves and dryers commonly come with both sets, and I've seen furnaces that can be converted. I've never seen a water heater than can be converted, though it is in theory possible.

The hard part is an entire neighborhood must be converted at once. You have all summer to convert the furnace, but things used all summer like stoves, or water heaters have to be done for the entire neighborhood in one day. This means a lot of logistics to get the right parts and labor in place to do the work. Though if people are willing to accept propane takes outside their house you can delay a bit, but it needs to be done before everyone needs heat.

You forgot heat pumps, that is what will be everyone switching to. It's more efficient to burn propane centrally in a power plant and use the electrical grid to power heat pumps than distribution/burning of propane locally.

While heat pumps are a great idea, where I live they don't work on the coldest days so you need some other backup. Burning propane on those cold days is more efficient than a central power plant.

Offtopic... does anybody have a good link to find papers that have been written after sci-hub stopped adding papers?

My desire to read papers like this outstrip my funds to do so.

C3H8 + 5O2 => 3CO2 + 4H20

reminder that propane burns into CO2 - this process doesn't actually unlock any new energy source, it merely just reverses a reaction that has already taken place (presumably with electricity or some other form of energy)

this isn't some kind of miracle infinite energy source to solve climate change woes, more like an interesting way to convert one usable form of energy (electricity) into another (a petrochemical)

But this is perfect. A complete reversion of the reaction, without any additional interesting inputs or intermediate stages.

You can imagine a closed-cycle, isolated "battety" that discharges into sparkling water, and charges back into fuel and oxygen.

This is exactly the miracle solution that can turn CO₂ back into fuel, which can be burned again in existing ICEs and gas turbines, then turned into fuel again, powered by solar electricity.

Collecting and concentrating the CO₂ is going to be a task in itself, but things like power plants or steelmaking furnaces offer high-concentration, pre-heated CO₂.

that would be cool, but wouldn't something simpler like electrolysis of water into hydrogen/oxygen work much better? I haven't the effort to do the math, but it would require less steps, less complexity, and less cutting edge catalysts with unknown lifetimes

No.

It's hugely inefficient, so it requires more solar power.

Hydrogen is hard to store and use; unlike propane, it penetrates through plastics and even metals. Hydrogen is a good rocket fuel if you need top performance and cost is no object.

Propane is very convenient, and can be reused across the existing LNG infrastructure.

Hydrogen is very difficult to use as a direct fuel source. This recent video gives a good overview of all the challenges a hydrogen engine has to overcome: https://youtu.be/DGL5g91KwLA

thanks

The value lies in the fact that we already have a lot of infrastructure (including storage) that uses propane.

By switching from fossil propane to this green propane we can indirectly 'electrify' entire swaths of energy consumption.

It's scary to me how good this is. Because if it works, we can effectively continue as normal. Which is not to be expected, and might cause us to slack off since the pressure is gone.

It would work well with wind and solar as energy storage, or even tidal or geothermal. Making it great for storing power from variable power systems. Propane is extremely easy to distribute.

What form of CO2 does this work with? I suspect highly concentrated, not the minuscule amounts in ambient air.

Too early. I'm still healing from the super-conductor that wasn't.

Or, the superconductor that is in US or maybe Chinese government labs.

Pk-99? All the scientists that know about material science were sceptical.

The material isn't that hard to make, the actual testing is the hard part.

But of course maybe there is a secret superconductor somewhere in some lab. Maybe there is also a invisble teapot circling the moon. We will never know.

I don't like those techs because they don't guarantee that they will offset fossil fuel extraction.

What's really needed it's culture change on growth and consumption.

The best technology is light technology.

If the price is competitive the market will guarantee it. Otherwise regulations can.

Why would you oppose technological solutions in favor of ideological ones? Unless of course you don't care about solving the problem...

Energy policy based on being "nice" will never have significant longevity.

We(as humanity) has done this several times in the past. If there is an alternative we could regulate our way out of not harming ourselves. It sure takes time but it has happened in the past. Cue. Asbestos, use of Lead pipes, use of CFCs, now ongoing reduction of single use plastics.

Except it already has. Car emissions regulations are a good example. Not just regulations on manufacturers either. Look at London's ultra low emissions zones quickly pushing folks to go electric.

Would be nice if instead of using car emissions as a boogeyman they focused on the cargo shipping industry who burn metric fuck tons of bunker oil instead of using alternative fuels. Instead you just get taxes in the guise of 'fixing the environment' by penalizing the working class who in reality contribute very little to co2 and nox emissions.

>What's really needed is culture change on growth and consumption.

It is not.

At no point in the history of human civilization has growth been static. It will not ever be. It will and should be exponential. Figure out how to make that happen or go join one of the religious groups that stop using new technology.

We want, need, and benefit from growth.

Our energy source just needs to change, and is changing. Plenty of earthbound solar and nuclear to satisfy our growth for a good while. There isn't enough fossil fuel around anyway if we wanted to keep growing with it.

By the time we need it we can produce plenty of energy in space. Think square miles of solar arrays in solar orbits fixing energy into whatever passes for a future battery while also colocating with asteroid smelting and refining facilities.

> There isn't enough fossil fuel around anyway if we wanted to keep growing with it

I in all seriousness love this angle and find it super refreshing, the puny amount of oil on this tiny planet isn't enough to satisfy human ambition. We should own the stars.

Very little oil among the stars, though... Very little sunlight or wind on route either.

Fair amount of hydrogen. Get fusion working and you don't need much.

ITER estimates they need 250 kilos of hydrogen per year for a 100MW plant, half deuterium half tritium. That's 125k/2 + 125k/3 = 103k moles of gas, so ~100k * N atoms of hydrogen. The interstellar medium density is given by the wiki as 10¹² molecules/m³, of which 70% is hydrogen. So, we need to absorb 100k moles * N / 10¹² = 6*10^16 cubic meters of ISM to get enough hydrogen for a 100MW plant on board the ship for one year.

And this assumes that the hydrogen is available in exactly 50/50 deuterium/tritium combinations, which seems extremely improbable given that tritium has a very short half life (a few years at most).

I very much doubt that refueling from the ISM is plausible.*

100MW is either a large ship or a fast ship.

100MW is more than the energy consumption of 50,000 homes. To collect 6*10^16 cubic meters/year at an average speed of 100km/h (walking pace in outer space), you'd need a "net" of less than 10km x 10km, which is completely plausible for a ship that large.

If you have a small ship using the reactor for thrust, at 1% of the speed of light the width of the "net" is much smaller.

And tritium is used in existing designs but we're still in the infancy of the technology. Stars fuse deuterium with neutron-free hydrogen (protons), and make the deuterium themselves.

> There isn't enough fossil fuel around anyway if we wanted to keep growing with it

There is plenty of coal left and you can make oil out of it, so we could burn fossil fuels for centuries to come if we don't mind the side effects .. otherwise agree.

>At no point in the history of human civilization has growth been static.

From the 1200s to 1600s England went through a period of zero or extremely low growth.

Mostly due to the plague killing some massive fraction of the population in the 1300s?

> At no point in the history of human civilization has growth been static.

Generally: correct. So far.

> It will not ever be.

Yes, it will. This will be forced by 2 factors:

a) The Earth we live on is essentially a closed system. Yes @ some point we might be able to mine asteroids, use extraterrestrial energy sources, move people off-planet etc. But this depends on technology to make this feasible. Until such technology appears, we're stuck on this rock. And thus, have to make do with what this rock provides. Which is a lot, but finite.

b) The laws of physics (those related to energy, in particular).

The "eternal growth" is a classical economist's view. Which (sadly) is very pervasive.

Historically, population growth, raw materials consumption, energy use, and technological progress have been tightly coupled.

But this coupling will be loosened.

Technology will probably keep progressing ..somehow.

Energy use might increase if eg. we can get nuclear fusion to work. Even that is not 100% a given, btw (apart from the timescale). How energy is generated will be very different 30..50y from now.

But raw material consumption can NOT keep increasing. There is finite amounts of [insert material here] on this planet. Never mind agri stuff like phosphor, pollution, or the amount of CO2 we can release 'safely'. And it's not feasible to recover 100% of any reserve.

Same with population. Earth is already too crowded. Would you want continued growth until entire Earth surface is covered with humans? Stacked 50 humans high?

No? Then population growth will stop. Not to mention that population growth eats any gains made elsewhere (10% more raw materials, 10% more energy, 10% more food, followed by 10% more people = back to square 1 despite the gains).

Historically this wasn't a problem because those limits weren't hit (well... they were, locally, which caused past civilizations to collapse). But we are hitting those limits now - globally.

It's this decoupling of growth factors that's a hard pill for people to swallow. Especially economists & politicians.

But don't worry! The laws of physics are very reliable.

> @ some point we might be able to mine asteroids

Essentially, we can do this now. There is no real technological barrier and several organizations are actively developing solutions. We're at over a billion dollars invested. Go read a report on the status of things [1]. This isn't far off science fiction but something practical folks are throwing money after.

1. https://www.mordorintelligence.com/industry-reports/space-mi...

> At no point in the history of human civilization has growth been static.

This is a bold and hard to believe claim. Weren't the Dark Ages in fact a reversal? Can you provide a source for your claim?

> At no point in the history of human civilization has growth been static.

So? "The limits to growth" was published in the 70, you should try to educate yourself on finiteness of earth.

Good luck with your space dreams. Smells like the Elysium movie.

> At no point in the history of human civilization has growth been static

Indeed countless civilizations collapsed once they depleted natural resources.

"Grow, grow, grow", said the obnoxious cancerous tumor...

And then it killed its host and died. The. End.

Sometimes i think one of the biggest hurdles to environmentalism is greens insisting on wishful, return to edan, thinking instead of practical solution.

Convincing everyone in the world to do a massive cultural change involving large standard of living decreases is not happening except at the point of a literal gun. The world can't afford to wait for impractical solutions.

Expecting technology to solve all our problems is just as wishful.

Everyone who made it out of childhood thanks to antibiotics and vaccines should probably reject takes like this.

Technology has solved the vast majority of all of the major problems of human beings throughout all of human civilization. Agriculture is technology. Writing is technology. Inks and paper are technology. Pharmaceuticals are technology. Heart surgery is technology. The modern industrial supply chain is technology. Transportation is technology. Seatbelts and blood typing to enable blood transfusions - technology.

It is theoretically possible that technology could solve the problem of death itself.

To make claims to the contrary, which would be extraordinary, something a great deal more substantial than a handwavey dismissal is required.

Sure, we now survive childhood based on vaccines, but remember that there was a time between the disease appearing and the vaccine being developed, and in that time we used simpler methods to try survive.

The issue is not what the world will be like in 200 years when the climate crisis is solved, it's how we get there. Tech takes decades to research, design, and develop; we need ways to limit the damage that can be implemented in years to limit the effects we'll see in our lifetimes. I agree tech will be the end solution, but continuing to burn at current rates while we wait for that is going to cause, or already is causing, massive problems.

> Sure, we now survive childhood based on vaccines, but remember that there was a time between the disease appearing and the vaccine being developed, and in that time we used simpler methods to try survive.

50% of children died before their 5th birthday

I don't think anyone is talking here about going without antibiotics or modern agriculture. More like curbing excess production of concrete (making construction more sustainable) and metals (reducing automobilism and other wasteful means of transport).

The revolutions or sometimes evolutions resulting in democrat nations with regulated market based economies are what allowed the rapid pace of innovating you are praising. Those revolutions were radical social changes.

Nothing in your post rebukes the claim made by the parent.

IMO, we need both - people screaming out loud to reduce consumption and rooting for truly green technologies that create a revolution. While some silent practical warriors change the status quo one kg of CO2 at a time until those revolutionary changes kick in.

I think no sensible person would protest a more sustainable solution than the current fossil burning tech even if it is not 100% renewable.

> IMO, we need both - people screaming out loud to reduce consumption and rooting for truly green technologies that create a revolution.

Nuclear fusion for energy generation purposes has been promised for, what, 60 years now? Hoping for that to eventually succeed will only lead to one thing: it won't work out and whoops, suddenly humanity is out of options because everyone had refused to change in the hope for a miracle.

It is more sensible to prepare for the worst case now.

Fortunately nuclear fisson technology has been here for a while and solves most of the immediate problems we have.

Too bad we barely used it.

We barely used it because it's a textbook case of overpromising and underdelivering.

A nuclear project on average has a probability of going over time and budget somewhere between an IT project and organizing the Olympics.

These are not great odds, especially that renewables are on the other end of the same scale.

Who promied what exactly. One president onetime said it was gone be "to cheap to meter" so now it can ne er be used because of "overpromise". Who gives a shit?

It delivers plent. And if we actually developed fission technology beyond the 1970 we could do so so much more.

Nuclear projects in Western nations done as low priority "keep the industry alive" individual projects are often late.

But historically when large amount of investment is made, you get very large amount of energy quickly.

Lets not pretend that every renewable project is perfectly on time on budget either. Its just that those are smaller and on project being late isn't news worthy.

India just finished reactors very cheaply. UAE and South Korea just showed an amazing buildout of nuclear that could be scaled to much larger easly.

Finlands project took a while and was expensive but now they have great reactor that produces lots of power for the next 80 years or more.

Frnace literally made its grid green in 20 years and they have had cheap energy since.

Fission is amazing, fusion is totally unneeded. Not using fission more is one of the dumbest things humanity ever did.

It is one of those things that genuinely polarizes people’s opinion. On the one-hand you have a solution that used carefully could simply replace fossil fuels for a large set of use cases. On the other hand, as little as it may be, their wastes are an undealt problem that is only wish washed away. Ironically, it also needs one of those revolutionary discoveries before it is truly safe.

No, it’s more a narrative issue than anything else.

Nobody says we should go back to Stone Age but we should unleash our narratives of what is a nice future.

Living in a world where everyone is eating healthy local food, where you live longer because it’s safe to use your bicycle and hard to use the car. Living in a world where you can walk everyday because there are trees to give you their shadows. Living in a world where work is meaningful. For me that’s a bright future.

Nobody says we have to abandon all of our technological and cultural advances but that we have to prefer some over others.

Like my grandfather said, plant 2 trees when you build your home and you’ll never need air conditioning. His idea wasn’t that you should ban A/C but rather that you can use it way more efficiently just by adding some shadow.

That’s the world we must live in now : consuming energy is ok but not if it is a countermeasure to our own stupid decisions.

It’s the same with cars. Ok they are nice sometimes. But they are stupid if we use them to go in a far office with the same computer you have at home.

We don’t need to go back to Stone Age but we need to dream of a future where we don’t use the energy for stupid things. And this implies being able to see what is stupid and who have interest in keeping a given stupid thing, stupid.

> Living in a world where everyone is eating healthy local food, where you live longer because it’s safe to use your bicycle and hard to use the car. Living in a world where you can walk everyday because there are trees to give you their shadows. Living in a world where work is meaningful. For me that’s a bright future.

That sounds nice and all (although as a canadian, too much heat due to lack of shade is definitely not the issue around here ;) ). I'd even go as far as to say that those types of life style changes have an important part to play. However, even if implemented to the fullest extent possible, i don't really think it solves the greenhouse gas problem by itself or even comes close.

> i don't really think it solves the greenhouse gas problem by itself or even comes close.

Well, yeah...ok, everyone rides around on bikes. Someone has to make the bike. Is it done by hand? How do you scale that to 8B people? Or is it done by a scaled industrial process, and if so, how do you power this?

The answer to these questions isn't to limit technology, it's to limit population. The scale of our population is the cause of all of these strange threshold-breaking externalities we're now facing. And you can't point at the technology and say "SEE?! It's ruining everything!"

The technology is just a companion to our population. Real primitivists should be arguing for drastically reduced population (however that is achieved ethically), not a reduction of technology.

This is exactly what they did. The reduce population movment was big and is big.

Read "The Population Bomb" its literally what people were obcessed about back then. Save the enviornment because of old zero ideas that German generals really licked too.

The podcast "If books could kill" did a great episode on this book.

Its an incredibly dumb amd harmful idea but its sticking around.

As someone who dislikes physical movement or being outdoors, this sounds terrible. Local food is often heavy in ingredients I don't like or to which I am allergic, or doesn't fulfill my nutritional needs and desires. This is not the idea of an ideal world for many modern people.

I'd much rather we solve the issues related to being sedentary with technology than we try to figure out how to make everyone bike everywhere, which most people don't want to do, even given the option. I don't wash my clothes by hand and I'm not sure why bicycling is seen as some ideal correspondingly. I'd take a 200 year perfect artificial heart over safe bike lanes. I'd take better solar (to run more AC and dehumidification) over more trees. I've swallowed enough bugs whilst cycling for more than one lifetime.

Your position, to me, is still just a yearning for historical lifestyles that we abandoned en masse for good reasons. Using energy on air conditioning and transportation are perhaps the least stupid things one can spend energy on - right alongside spending energy on washing machines for your bedclothes and underwear, which nobody seems to regard as some insanely wasteful luxury. Why is energy for heating seen by europeans as OK when energy for cooling is regarded as a senseless waste? It's just cultural bias and tradition.

When the majority of humans live in space or on bodies without an atmosphere, this whole "fresh air and trees" meme will finally die, I hope.

The heating vs cooling this always gets me. Living in Arizona and cooling your home 30-40 degrees down with a 50% carbon-free electricity mix and 3 or 4x COP is seen as unsustainable, but living Illinois and heating your home 50-60 degrees up by burning fossil fuels is fine.

> Why is energy for heating seen by europeans as OK when energy for cooling is regarded as a senseless waste?

I'm not the type of person who would want everyone to cycle - chiefly because four wheels > two everywhere and everytime, but there's an argument to be made against overusing AC, namely: you're just moving heat around and producing some in the process, so the net effect is that the area around you gets extra hot.

AC is a pretty blunt tool and there are ways of keeping places cooler without it.

While I geneally agree. There are tons of degrowth advocates who go way further with this way of thinking.

> Convincing everyone in the world to do a massive cultural change involving large standard of living decreases is not happening except at the point of a literal gun.

...or when you have millions of people on the Western borders fleeing from climate change and its side effects (we're already seeing just how cruel politicans behave towards the relatively small amount of people at the borders currently - imagine how the situation will look like with just 10x as many!), or entire of our states being devastated by wildfires, hurricanes or tornadoes. Probably it's going to take the latter until politicians wake up, when the situation is undeniable even to the hardest MAGAts and other deniers.

The key thing is: humanity is using more resources (no matter if you're talking about food, drinkable water or fuel) than nature can regenerate, each year. We are currently digging into reserves that took (in case of groundwater) sometimes many millennia to create.

> The world can't afford to wait for impractical solutions.

It can't afford doing nothing, because continuing as-is without managing sensible degrowth may work out for our generations, but the ones born after 2010? They're fucked.

The most efficent conversion from fossil to green happen in France and it had nothing to do with envoirmentalism. In fact envorionmentalism for most of the 20th century did more to prevent replacment of fossil fuel then it did to reduce it.

Nature bats last, and humanity is the ball.

I really fail to understand how you can push "light technology" while using a modern computer connected to the Internet - both are very very far away from being light in terms of technology involved. In fact the technology making both run is incredibly complex/sophisticated with a high environmental impact resulting from production, assembly and shipping of components required to make it work.

Wanna go light? Ditch your computer, phone and most of electronic/digital devices you use every day (for a start, then follow up with car and basically anything that depends on "heavy technology" to exist and run). But that is probably not the lifestyle you're imagining ATM.

you're attacking the messenger, not the message

im using a low performance computer, and computer have enough power to do things.

it's about the ressources spent to make a computer.

"And yet you live in a society" is such a reddit-tier rebuttal, that's so embarrassing for you.

Even if I believed degrowth was a good solution (I mostly don't), I would still hope for the success of these technologies as a backup plan.

The answer to this kind of claim is in the book "The Wizard and the Prophet", which was reviewed on ACX/SSC here [1].

To summarise the review: there are two approaches to solving humanity's big problems, from food production (mostly solved) to climate change. The Prophet approach is to go around saying "we must live within our means!" and "technology bad!", and the Wizard approach is to seek techological solutions. And as the reviewer writes:

> Though Mann insists from the start that the book is not meant to advocate for or condemn either side, it was initially difficult for me to read it as anything but two-and-three-quarters cheers for Wizardry.

It turns out that Prophets tend to be misanthropes at best, and racists at worst. William Vogt, Mann's archetypal Prophet, founded (according to Mann) much of modern-day environmentalism but also (according to the review, which I personally trust) called people in India "backward populations" who "breed with the irresponsibility of codfish". Says the reviewer:

> _Which_ people deserved to live in harmony with nature in the ensuing pastoral utopia and which would be relegated to the dustbin of history was not an exercise they left to the reader.

(Meanwhile Norman Borlaug, the Wizard, was busy producing a Green Revolution that ended up raising rice yields in India from 2 to 6 tons/hectare and lowered rice costs from $550 to $200 a ton, according to the Wiki page.)

[1] https://astralcodexten.substack.com/p/your-book-review-the-w...

Its simply incomplete.

The problem is also that there is the burocrate. And the burocrate in the 60s made society into a car depended nightmare.

And most modern prophets are mostly saying "he can we rethink some of the policies adopted".

Reply on news.ycombinator.com