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The Beetle Sphere by Ichwan Noor. Photo by Brett Jordan
It’s not science fiction. Innovations in automaking are already incorporating carbon dioxide into new vehicles you can buy today, from the body to the tires, from the fittings to the fuel in the tank. Here’s how the upcycled car is steadily taking shape.
A year from now, a truck wends its way through scenic Swiss villages, delivering milk from the country’s famous Alpine cows. Like almost all light vehicles today, it is powered by gasoline formed underground over millions of years and pulled from the earth thousands of miles away. But there is a crucial difference.
The carbon dioxide released by the internal combustion of gasoline in this milk run does not all escape into the atmosphere, for this truck has two gas tanks: one for its fossil fuel, but also a second one to store about 90 percent of the greenhouse gas it generates as it putters about the countryside.
The technology that can make this work, devised in a Swiss university and now spun out into a startup called Qaptis, cleverly combines reversible thermochemical reactions to liquefy CO2 before it escapes out the tailpipe. The captured pollution can then be upcycled into fuel that replaces fossil gasoline—or into plastics and carbon fibers used to make new vehicles. As a bonus, Qaptis claims, the system consumes heat as it works, and thus could chill a cargo of milk en route to its own transformation into cheese, chocolate, and fondue.
“You have a sort of magic system,” says François Maréchal, a professor of chemical engineering who led development of the concept at the Swiss Federal Institute of Technology in Lausanne. “It uses an existing engine and an existing truck. Add a box on the exhaust pipe, and you get liquid carbon dioxide that you can sequester into a useful product.” The US startup Remora Carbon is commercializing similar technology developed at the University of Michigan.
This truck has two gas tanks: one for its fossil fuel, but also a second one to store about 90 percent of the greenhouse gas that it generates.
A bolt-on retrofit that makes existing gas vehicles cleaner than new electric ones? (Building an EV comes at a hefty upfront cost in emissions.) That does seem like a magical answer to motor vehicles’ direct carbon footprint, which accounts for about a third of the greenhouse gases emitted by the United States and other rich nations.
Or is that “magic” just a devious trick? After all, cars and trucks drive many of the least sustainable aspects of the global economy: rampant sprawl, growing air pollution, and hundreds of thousands of road deaths every year. We need more than a technological fig leaf to allow us to keep motoring on. To remedy the damage that automobiles do to our environment, we will need to steer the institutions, architecture, and social systems that inextricably depend on passenger cars in bold new directions.
From a climate perspective, the best thing to do with captured CO2 is to immediately lock it away deep underground. That’s what Climeworks in Europe and Carbon Engineering in Canada are doing. Both run facilities that sequester CO2 from the atmosphere at a commercial, if not yet industrial, scale. But that process is expensive and sometimes impractical.
“If you look at the carbon capture that’s going on around the world, it’s around 40 megatons each year—a thousand times less than is being emitted,” says Peter Styring, director of the UK Centre for Carbon Dioxide Utilisation at the University of Sheffield. “And most of that goes into enhanced oil recovery to recover yet more fossil oil.” Much of the rest currently goes into producing fizzy drinks, fertilizer, or other chemicals—which means that the gas soon finds its way back into the atmosphere.
Upcycling aims to pull off an ambitious trifecta: lock up carbon dioxide for centuries, reduce the production of fossil fuels, and return profits to investors. It’s not science fiction. Innovations in automaking are already incorporating carbon dioxide into new vehicles you can buy today, from the body to the tires, from the fittings to the fuel in the tank. Here’s how the upcycled car is steadily taking shape.
Let’s start with the exterior. Once bent from carbon-intensive steel, cars are now largely molded out of petroleum-based plastics. One climate-friendly step would be to switch to fibers and composites made from upcycled carbon.
“Carbon fiber is sort of a Holy Grail for carbon utilization,” Styring says. Composites made from carbon fiber are stronger, stiffer, and—crucially—lighter than steel or aluminum.
“Whether in aviation or automobiles, you need lightweight materials to meet your climate goals,” says Thomas Brück, a synthetic biotechnologist at the Technical University of Munich (TUM). “If your car is driven electrically, your range is dependent on the weight of your chassis.”
And batteries are really heavy. Kia’s all-electric Niro compact SUV weighs 335 kilograms (740 pounds) more than the almost identical gas version. That’s like carrying a polar bear in your trunk.
Carbon fiber is so expensive that it’s rarely been used outside luxury brands such as Lamborghini and BMW. But that could change quickly. Chinese factories have been ramping up production of carbon-fiber cars, driving prices down.
About 90 percent of carbon fiber today is made from a precursor called polyacrylonitrile (PAN), typically made through a process that involves ammonia and fossil fuels such as naphtha or natural gas. When PAN is spun out under extremely high temperatures in the absence of oxygen, it carbonizes to fibers that can be stabilized and wound into carbon fiber. Today, making a pound of carbon fiber consumes about 14 times as much energy as goes into a pound of steel, and the fiber costs more than ten times as much.
But chemists have been working for years on greener methods for making PAN—and thus carbon fiber. Brück believes there is a price-competitive, carbon-negative route to upcycling carbon dioxide into carbon fiber. The key ingredients, he says, are algae and seawater.
To efficiently upcycle carbon dioxide into carbon fiber, the key ingredients are algae and seawater. Above: A beam made of carbon fibre-reinforced granite is load-bearing like steel, as light as aluminium and extremely durable. ©KoljaKuse/TechnoCarbonTechnologies.
“The only low-temperature process that can convert CO2 into something usable is photosynthesis,” he says, noting that microalgae such as Nannochloropsis salina have up to four times the photosynthetic efficiency of any terrestrial plant—and grow ten times faster. But many past attempts to upcycle CO2 using algae have left disappointed investors and failed startups in their wake.
“The big mistake that most of the early algae companies made was to use freshwater, which is needed for agriculture and is prone to contamination,” Brück says. TUM’s algae can thrive in brackish, open-air ponds. To find such salt-tolerant varieties, “we and our partners traveled the world to build our collection of algae strains,” he says. “Right now, there are about 20 kinds of algae in industrial use. We have 150,000 strains. And there are more to be found.”
As they soak in the sun, the algae gobble up tiny bubbles of CO2 that the researchers pipe in under water. The microbes then metabolize the simple gas into more complex oils. Harvested and dried, these algal oils can be chemically processed into fuels and glycerol—the first step in producing PAN.
Turning PAN into carbon fiber still requires a lot of energy, but Brück has published a techno-economic analysis suggesting that the end product, which is indistinguishable from fibers now on the market, can be net-carbon-negative—storing more carbon than is released in its production—so long as the necessary heat comes from carbon-free sources, such as concentrated solar power or a nuclear reactor.
It helps that these algae have a healthy appetite for nitrogen. They feast on nitrogen-rich manure and agricultural residue that might otherwise be spread on—and then run off—fields, disrupting aquatic ecosystems and generating nitrogen oxides that are themselves potent greenhouse gases.
And with a few tweaks, TUM’s process can make not just the fibers but also the resins that bind them into the final composites. Brück showed Anthropocene a block of its composite, which incorporates granite among the carbon fibers: it had been made into a tough, lightweight, electric scooter.
“We’ve demonstrated that it’s doable—that we can produce resins and carbon fibers with the same physical features as those from an oil well, but completely based on carbon dioxide assimilated by the algae,” he says.
The German government has chipped in 12 million euros ($14.5 million) to help TUM develop test ponds that simulate the sunlight and weather conditions of almost anywhere on Earth. Brück will use those to optimize algae farming and the other steps in the production process, with the aim of scaling it up.
“People are interested in the carbon fiber. But because the next steps are unconventional for a classical industrial approach, it’s very hard to find investors” who will buy into the vision, he says.
Imagine a car that reuses the carbon dioxide it emits
(click on the yellow dots to see how automakers are already incorporating carbon dioxide into new vehicles you can buy today)
CO2 is more efficient and less polluting than traditional refrigerants
Upcycled carbon fiber for lightweight details
Plastic accounts for about half of all the material in modern cars
Upcycled structural carbon fiber for chassis
Carbon fiber is stronger, stiffer, and lighter than steel but is currently very energy-intensive to make
Upcycled carbon black for tires
The rubber in tires is reinforced by carbon black, a fine carbon powder that can now be upcycled
Upcycled foam and textiles for door panels, seat covers, and arm rests
Materials for door panels, seat covers, and arm rests containing upcycled CO2 are already available
Several companies are working to produce normal gasoline that has been upcycled sustainably from CO2
Upcycled plastics for wiring and cables
Modern cars contain several miles of plastic wiring and cabling. Upcycled plastic can be used here, too.
Making a car’s body out of carbon sucked from the atmosphere is a neat trick, but a car has only one body. To make deep cuts in emissions today, technologists must tackle a harder challenge: using carbon from the air to refill the tank with carbon-neutral fuel, over and over again.
The vast majority of the roughly 1.4 billion road vehicles on Planet Earth today run on gasoline or diesel fuel. Though a gradual transition to EVs is under way, researchers at the University of Toronto have calculated that the planet cannot shift to electric passenger cars fast enough to hit climate targets.
“Even if every country in the world banned the internal-combustion engine by 2035, you would still have 800 million gas cars on the roads by 2050—and we’d have used over half our remaining carbon budget,” says Rob McGinnis, founder and CEO of Prometheus Fuels.
So replacing today’s vehicles will take too long. And retrofitting them to capture their exhaust gases, as Qaptis and Remora envision, probably isn’t practical at sufficient scale. But McGinnis sees a third way: upgrade internal-combustion engines to run on fuel upcycled from atmospheric CO2.
“If I build a factory to make 500,000 new EVs a year, I’m not going to make a huge impact,” he says. “But if instead I build a factory that makes 500,000 devices to produce carbon-neutral fuel, each one of those devices can decarbonize a thousand gas cars. It’s three orders of magnitude more impactful.”
As with so many climate-sparing innovations, the big hurdle is price. “If you’re going make a fuel, the worst thing to start from is CO2,” says Howard Herzog, a senior engineer with MIT’s Energy Initiative and coauthor of the IPCC’s 2018 report on carbon dioxide capture and storage. It’s not just that direct-air capture of CO2 is costly. Liquid fuels store energy in the bonds among carbon, oxygen, and hydrogen atoms, so upgrading CO2 involves adding hydrogen. And green hydrogen, made from renewable sources, is still expensive and hard to handle.
But McGinnis realized in 2018, as renewable energy prices were plummeting, that the intermittent electricity from wind and solar farms could be harnessed to make renewable liquid fuels from cheap components and the cheapest of chemicals: water. Prometheus’s self-contained process, called the Titan Fuel Forge, turns air and water into fuel in four stages.
“If I build a factory to make 500,000 new EVs a year, I’m not going to make a huge impact . . . But if I build a factory that makes 500,000 devices to produce carbon-neutral fuel, each one of those devices can decarbonize 1,000 gas cars. It’s three orders of magnitude more impactful.”
The first stage moves the carbon from gas to liquid form. Large fans blow air over an enclosed waterfall, dissolving atmospheric CO2 into water to form a weak carbonate solution. Think seltzer water. As a bonus, McGinnis claims, water vapor also condenses into the waterfall, so external freshwater is not needed to sustain the process.
Stage two is where the cheap, carbon-free electricity comes in. Running currents through the aqueous carbonate electrolyzes the molecules, forming alcohols and releasing oxygen. Prometheus argues that this approach is more cost-effective and energy-efficient than simply using the electricity to split hydrogen from water and then combining that with concentrated CO2.
The third stage uses a membrane perforated by carbon nanotubes to sift the alcohols out of the water and pass them along to the fourth and final stage. There, inexpensive, nontoxic catalysts break apart the alcohol molecules and recombine the pieces to create gasoline, diesel, or jet fuel. The reusable catalysts, licensed from Oak Ridge National Laboratory, are expected to last for years.
“It’s not like cold fusion, and we didn’t have to discover any fundamental science,” says McGinnis. “Our advantages are that we don’t have to produce a pure CO2 gas, and the cost to capture CO2 is super cheap because it’s built into our system.”
What Prometheus does need is a lot of low-priced green electricity—and a regulatory playing field tilted in its favor. It found both in sunny California, where solar panels are becoming ubiquitous and a low-carbon fuel standard (LCFS) rewards companies for producing carbon-neutral fuels.
“Right now, the LCFS credit is around $175 a ton for CO2, and our cost is less than $50, so the balance goes to helping us to build out our process,” says McGinnis. “We’re going to launch retail gasoline this year in California at $3.50 , and we’re going to make money on that.” The average price of a gallon of gas in Los Angeles today is upwards of $4.60.
McGinnis plans for 100,000 Fuel Forges a year to roll off the production line of a (yet unbuilt) factory with a moniker that might make Elon Musk smile: Meta Forge. “Even allowing that solar and wind only run about half the time, the output of one year’s operation of a fully functional Meta Forge is about 50 billion gallons of fuel,” he says. For comparison, all 14 fuel refineries in California together produce about 15 billion gallons a year.
“If you want to replace all the transportation fuels in California,” McGinnis claims, “we’d need 3,000 square miles of desert for solar.” At this scale, McGinnis thinks his fuels would be price-competitive, without significant subsidies, across much of the world. “If you replace all oil and gas with power-to-fuel or power-to-product, you can remove 20 gigatons of emissions per year—and that’s enough to stay below 1.5 degrees Celsius,” he says.
Prometheus has yet to publish technical details of its system or demonstrate proof of feasibility with a pilot plant, so some skepticism is warranted. But American Airlines revealed in July that it has signed a deal with Prometheus to buy 10 million gallons of net-zero-carbon fuel, once the plants are up and running.
Carbon-neutral technologies like this do not sequester any greenhouse gases, but they do at least leave fossil carbon in the ground. “It’s making that carbon work twice rather than just once,” Styring says. “So it’s becoming a partial circular economy rather than a simple linear economy.”
Switching completely to EVs will be a decades-long project, even in the richest countries. In the meantime, Prometheus’s technology could help cut emissions faster by taking advantage of the cars, trucks, and gas stations we already have.
Tires, Wires, & the Interior
Open the doors and lift the hood, and you can spot other opportunities to upcycle carbon into cars. In particular, the power train and electronics—plus the big battery pack in electric vehicles—all leave hefty carbon footprints. Engineers have been working to decarbonize these components as well.
One strategy is to repurpose the carbon from upcycled CO2 into one of its elemental forms, such as graphite. Because it is almost totally inert, elemental carbon can be used and then safely disposed of in landfills, where it will remain locked away virtually forever.
Tiny tubes of graphite just one atom thick, known as carbon nanotubes, are by some measures among the strongest and stiffest materials ever discovered. Prometheus Fuels uses nanotubes as highly selective filters, but they also have unique electrical qualities that could enable new computer chips, batteries, and sensors.
Solid Carbon Products, a startup based in Utah, is making elemental carbon of various kinds by reacting carbon dioxide with hydrogen in a heated, pressurized vessel. The company says that it can steer its process to make nanofibers, nanotubes, or a fine powder used in paints and in inks, and to reinforce the rubber in car tires.
Styring points out that the scheme consumes large quantities of both green electricity and green hydrogen. But its main byproduct is clean water. “It’s a really interesting technology and a really simple technology,” he says. Other companies, such as C2CNT in Calgary, are working on competing ways to make carbon nanotubes and other high-value materials from CO2 via electrolysis.
“Tying up carbon in solids is a very long-term solution,” Herzog says. “If it’s not going to get into the atmosphere for probably thousands of years, that’s all we really care about at this point.”
We’re already living in a warmer world, after all—which has us flipping on the A/C more often as we drive. And that itself is a problem, because the refrigerants in automotive air conditioners can be even more climate-hostile than carbon dioxide. So it’s a nice turnabout to see some carmakers rolling out models that can use upcycled CO2 as the refrigerant.
Volkswagen’s ID.3 and ID.4 electric cars, for example, can heat and cool their cabins using a carbon dioxide heat pump. Daimler has included the new technology as well in some of its luxury models. While CO2 is not quite so efficient at cooling as older refrigerants, it is better at heating. Because most cars in the world are still in chillier temperate regions, VW-funded research suggests that switching all passenger cars to CO2 heat pumps could save at least ten terawatt-hours of energy every year.
Covestro is now developing CO2-based thermoplastics that could ultimately be used in the several miles of wiring found in modern vehicles.
Run your hand over the interior of any popular car, and you’ll mostly touch plastic, which accounts for about half the materials by volume in a typical sedan, SUV, or pickup truck. Until recently, pretty much all that plastic came from petroleum. But the Swiss company FoamPartner is now marketing polyurethane foams that contain up to 20 percent carbon dioxide for use in armrests, door panels, roof interiors, and seat covers.
Covestro, a German manufacturer, developed CO2-enriched polyols that make these foams possible. “Using carbon dioxide as a source material is technically challenging because it’s very sluggish to react,” says Persefoni Hilken, a project manager at the company. A breakthrough came in 2008, when they identified a catalyst that guides CO2 to combine with propylene oxide, yielding polyols. A successful pilot plant in 2012 led to commercial production a few years ago. Covestro is now developing CO2-based thermoplastics that could ultimately be used in the several miles of wiring found in modern vehicles.
“The problem with plastics is that while they’re high in value, they’re low in volume,” Styring says. “They generate a reasonable revenue stream, but they don’t really address CO2 mitigation directly” at the scale needed.
Covestro has tried making polyols that incorporate more carbon dioxide—thus displacing more petrochemicals. But the material turns sludgy and difficult for carmakers to deal with. “If our customers had to change anything in their production setup, it would never have found acceptance in the market,” Hilken says.
Herzog raises another issue with plastic car components: the fact that most vehicles have a lifetime of just 15 to 20 years, after which some are incinerated rather than recycled or sequestered in a landfill. “How long will CO2 in these plastics stay out of the atmosphere?” he says. “If it’s several decades, that’s okay, but it’s not really good enough.”
More innovations, such as plastics that are recyclable as well as carbon-negative, are clearly needed. But innovation is inherently risky, and as Brück has found in raising money to work his CO2-eating algal farms, it can be hard to convince investors to pony up the capital needed. That’s where competitions, such as the $20 million NRG COSIA Carbon XPrize, can help spark ignition. The XPrize Foundation launched the contest in 2015 to motivate entrepreneurs to figure out new ways to create high-value products from upcycled CO2.
Two finalists for that prize are now working on upcycled fuels. Air Company, based in New York, uses direct air capture, catalysts, and renewable energy to produce alcohols, including carbon-neutral hand sanitizers and vodka. The company has set its sights high: it aims to make a new generation of rocket fuels for future space missions.
“It’s really challenging for us to compete with natural gas and fossil fuels without any sort of environmental incentives,” cofounder Staff Sheehan told XPrize. “But we can compete in outer space, where there is CO2 but no fossil fuels.”
Two finalists for the $20 million Carbon XPrize are using carbon dioxide, catalysts, and renewable energy to make fuels for jets and rockets.
Dimensional Energy, another finalist, is using photocatalytic technology developed at Cornell University to build a solar-powered system for upcycling CO2 into jet fuel. A prototype system now under construction will produce four barrels of fuel a day. If all goes well, the company expects to reach commercial-scale production in 2024.
C2CNT, whose upcycled nanotubes earned a spot in the prize’s semifinal round, showed how the visibility these competitions offer can pay off. It has since attracted significant investment from Capital Power Corporation, which operates coal, gas, and renewable-power plants across North America.
Indeed, investment in carbon-capture, utilization and storage startups is expected to reach nearly $1.1 billion in 2021, more than three times the total funding raised in 2020. In January 2021, Elon Musk pledged an eye-popping $100 million to a new carbon-removal XPrize.
So momentum for upcycling cars—and all kinds of carbon-intensive products—seems to be building. Although, as Herzog points out, “decreasing the generation of CO2 should be the bulk of our work,” it can only help to keep searching for—and finding—new and more profitable ways to put it to work here on the ground, where it can’t harm the climate.
Mark Harris is an investigative science and technology reporter originally from the UK but now based in Seattle, with a particular interest in robotics, transportation, green technologies, and medical devices. He is a contributing editor at IEEE Spectrum and writes for a wide range of outlets including The Economist, The Guardian, and Wired.
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