For decades there has been this tantalizing idea being pitched of pulling CO2 out of the air and using the carbon molecules for something more useful, like making plastics. Although this is a fairly simple process, it is also remarkably inefficient. Recently Caltech researchers have managed to boost the efficiency somewhat with a new two-stage process involving electrocatalysis and thermocatalysis that gets a CO2 utilization of 14%, albeit with pure CO2 as input.
The full paper as published in Angewandte Chemie International is sadly paywalled with no preprint available, but we can look at the Supplemental Information for some details. We can see for example the actual gas diffusion cell (GDE) starting on page 107 in which the copper and silver electrodes react with CO2 in a potassium bicarbonate (KHCO3) aqueous electrolyte, which produces carbon monoxide (CO) and ethylene (C2H4). These then react under influence of a palladium catalyst in the second step to form polyketones, which is already the typical way that these thermoplastics are created on an industrial scale.
The novelty here appears to be that the ethylene and CO are generated in the GDEs, which require only the input of CO2 and the potassium bicarbonate, with the CO2 recirculated for about an hour to build up high enough concentrations of CO and C2H4. Even so, the researchers note a disappointing final quality of the produced polyketones.
Considering that a big commercial outfit like Novomer that attempted something similar just filed for Chapter 11 bankruptcy protection, it seems right to be skeptical about producing plastics on an industrial scale, before even considering using atmospheric CO2 for this at less than 450 ppm.
Wait a second. The most effective process of producing plastics from CO2 is here for billions years already. Plants perfectly do exactly that – consume CO2 and produce even two plastics – cellulose and lignin in form of biodegradeable, strong and easy machineable composite plastic known to humans for millenia as wood.
What”s wrong with all that people who are looking for a way to pull CO2 from atmosphere? Just plant more trees, and that’s all. CO2 will be pulled, plastic and many other useful things including fruits and nuts will be produced. Almost at no cost, especially comparing with building complex manufacturing facilites. You want green planet – you will get green planet. Just get a spade and sprout, and do some extremely simple work with your hands. And it’s even fun to do that and satisfying to observe how the tree you planted grows, actually.
it would be a start, but you would need to couple it with ceasing extraction. Trying to counter ongoing oil extraction & combustion by out-planting it is not going to work.
One EV factory effectively plants 220K trees per day, by moving 1000 drivers off of gasoline. Globally we have about 40K drivers per day moving off of gas.
I wouldn’t object to anyone running around and planting more trees! But you need to plant about nine million trees each day – every day – to have a comparable impact to just quitting gas at today’s rates, and leaving the carbon in the ground.
Optimizing this idea a little, and making it a closer analog to creating plastic feedstock – plant bamboo plantations. Bamboo typically yields 30 tonnes dry mass per hectare per year, is readily converted into lumber or used directly for formed items like spoons and forks, and is high in cellulose, allowing bulk polymer production.
Until industrial CO2 extraction can rival Capital and O&M cost per ton of a plantation, or make some valuable, high quality output, it needs to stay in the lab.
+42
Trees take 20-50 years to grow before they’re big enough for lumber, and the efficiency of conversion from sunlight to biomass is less than 1%
Someone hasn’t heard of the hybrid poplar. You’re off by a factor of ten.
Lots of trees out there are a continuous coppice crop, or grow really really darn fast (and often both of those go together). Yes some of the most demanding uses we put wood to really does require that slow growing Oak to get to a giant size so it can contain the lumber desired, but that is far from the only option. For instance Balsa the tree is likely 10-20 years dead by the end of your estimate, and its growing to a giant size in 10 odd years – yes Balsa isn’t prime structural lumber but you can still do a great deal with it.
The capture and sequestering of CO2 like that is definitely not going to match capturing near pure CO2 waste from some other process and turning it into a plastic, but it is pretty much no effort process.
Plants are also doing same… save climate more tree propagate!!
Trees (and plants in general) pull CO2 at a horrifically slow pace. The hope is a mechanized process can eventually do it faster.
Also, many industrial processes GENERATE PURE CO2 which is currently released and in the future would need to be sequestered somehow for them to continue. This provides a possible sink.
It does not need to be from the atmosphere, it could be from the burning of coal or gas or any fuel or other process with an extremely high percentage of CO2. Nipping it off near the sources.
Exactly. Atmospheric CO₂ capture is always going to be less efficient then capturing it from the source.
If you want less CO₂ in the atmosphere you need to find out the most efficient way to do it. Making a older power plant more efficient is probably the most efficient way to reduce emissions.
Capturing it would only work if we have enough industrial processes to sequester this captured CO₂ as storing CO₂ underground has many downsides.
The most efficient way to reduce emissions in that case would be to turn the power plant off. It’s also the only realistic way, since increased efficiency generally results in increased consumption (see the Jevons Paradox).
Not if you still need the energy.
One of the criticisms leveled against renewable energy such as wind and solar is that the growth rate isn’t keeping up with global energy demand. It is said that no wind turbine or solar panel has ever caused a conventional power plant to switch off. At least on average. I personally don’t think this is true, but that’s for other reasons than the fundamental point of it.
In other words, as much as we’re building renewables, we’re still emitting more CO2 year by year from fossil fuels. In this situation, turning an old power plant off isn’t helping anything as it simply produces a shortfall of energy that will be replaced by any available means – which is going to be almost entirely fossil fuel based.
“Needing” energy does not necessarily mean you get that energy. It is possible to create and enforce a shortage, and this is the best way to reduce CO2 emissions. If we can cut off a nation’s resources in times of war, then surely we can do it to ourselves in times of peace.
@Anonymous
The solution to scarcity is to produce more of it and find ways to need less of it. Not rationing or taxing.
Everything runs on energy so rationing/taxing it will devastate the economy, so you will be sacrificing human lives. For every percentage of lower economic output life expectancy and quality of life drops significantly.
Degrowth has been debunked many times.
@c, yes and no – humans are really really terribly foolish creatures – for every ‘way to need less of it’ found without also finding ways to reduce the demand you just end up with individuals and companies finding ways to turn that improvement in efficiency into even more consumption.. For instance when a lightbulb was an incandescent power hog you’d generally only have one maybe two lights for the entire room, with CFL and LED you now have so many more lights lights each individually outputting a similar light level as the incandescent did, thus bathing the room in much more and much more even lighting, and the power consumption quite likely has gone up a little bit instead of down…
@c
Could you elaborate on the debunking of degrowth? I’m generally an advocate for lowtechmagazine type approaches and would be interested in seeing arguments against
For a while, until people figure out alternative means to access energy, which are usually worse. Turn off the power plant, increase electricity prices to reduce demand and… whoops, now people are buying propane cylinders and using gas stoves in the kitchen again. Ban propane, now people are using kerosene and other fuel oils.
You need a proper police state to keep people from innovating when they want something.
I don’t know who you’re listening to, but they’re saying falsehoods. Low cost renewables have forced coal off the grid, and made it much harder for new gas plants to be built. Look at ERCOT, where Texas legislators are clearly pro-oil and gas, have 5x the safety setback to a wind turbine as a gas well, and over 95% of new generation on the grid over the past decade has been wind and solar. Coal plants have been forced to shut down because they are not economically viable, even fully depreciated plants that are only paying for fuel and basic operating costs. Gas plants are marginal at best, and even with state subsidy program giving $7B for new gas plants, the interconnection queue is still over 90% wind, solar, and battery.
You’re right that we need to change faster, but US and EU CO2 emissions have been falling for a decade, and China is expected to have peaked in 2024, with renewable installations exceeding 300 GW/yr and headed toward 400GW/yr. BUILD MOAR SOLAR.
@Dude
Fortunately there are only so many sources of energy, and not many of them are cheaper than solar. Shut down the power plant, people burn gasoline instead. Shut off the gas supply, people buy solar panels from China and plant fast-growing trees for firewood. The job is done.
This entire scenario happened at a smaller scale during hurricane Helene. Power went down immediately, and gas ran out shortly thereafter. For two weeks, solar was king, if you had it. People adapt quicker than you think, you just need to pressure them.
I welcome a future where I can 3D print models using the atmosphere as my filament. I don’t so much welcome the one where the AI robots can do that and replicate en-masse and ensure the end of humanity.
If I’m reading the image (which is in the header) correctly then platinum, silver, and copper are expended as part of the electrocatalysis process. This system could only possibly be viable if you can reliably capture an reprocess those metals as none of them are cheap, especially platinum!
They’re catalysts, which means they’re in theory unchanged during the process. They’re still all in the same place in the same amount after you’ve run it for however many hours.
In practice, they get contaminated and eventually you have to ship them all into a refiner and get back clean catalysts, and very nearly the entirety of chemical engineering is the process of trying to extend your catalyst lifetime.
Why should this exist? I don’t want machines that create plastic trash from thin air.
Two birds, one stone.
Or was that a rhetorical question?
Everyday millions of tons of plastics are being produced & discarded, as well as new plastics being developed without any significant advancement in efficient, cost-effective recycling. These new plastics make recycling more & more challenging as a matter of compatibility or ability to separate. its been more than 50-60yrs since modern plastic production went into high gear with little interest in recycling or waste disposal by manufacturers & research organizations like The American Chemical Society & Amer Chem Council, who support NEW plastic development & advocating for the industry. Its easier & still cheaper to use fresh crude oil! We must begin demanding more regulations & government agencies do more, much more to resolve problem. in my opinion, research on developing more plastics from CO2 may be good science but UNTIL we stop drowning in plastic waste & potentially creating a catastrophic world collapse of food chain by plastic waste-blocked digestive systems of plankton, fish & any sea/land creatures that mistaken micro-/nano-plastics as food, we won’t be here tomorrow to make new plastics!