On paper, carbon capture is a simple proposition: Take carbon that we’ve pulled out of the Earth in the form of coal and oil and put into the atmosphere, and pull it out of the atmosphere and put it back in the Earth. It’s like hitting undo on the Industrial Revolution. And scientists can indeed yank CO2 out of thin air, except that the process is expensive, not very efficient, and morally complicated.
Direct air capture, as it’s known, is one of several negative emissions technologies, or NETs, that the National Academies of Sciences, Engineering, and Medicine explored in a massive report released last week. On the bright side of things, the authors found that strategies to get the Earth itself to reabsorb that CO2, for instance by building out forests, are effective and relatively simple. And that if we pour money into researching them, higher-tech options, like filtering CO2 out of the air and storing it underground, could go a long way in cutting back emissions.
Problem, though: Who would pay for a company to sequester carbon underground? It’s like buying a new car and sealing it up in a cave. How to you incentivize the development of a technology if you can’t get rich off it?
For a potentially powerful way to fight climate change, NETs sure are controversial. Some researchers warn that if we bet heavily on the tech and it doesn’t work out, like if it isn’t actually scalable, we’ll be in even bigger trouble. Another big concern is the moral hazard: If scientists develop efficient and cheap machines to suck carbon out of the air, we can all relax and go about emitting as usual. But as temperatures rise, pressure is mounting to reduce greenhouse gas emissions, fast. No NET alone can pull this off.
That said, these technologies could be an important part of the solution, a supplement to replacing fossil fuels with green energy. “Negative emissions have the potential to be a major new tool,” says Princeton University’s Stephen Pacala, who chaired the commission that produced the NAS report. “There is no ‘too late,’ and there is no ‘too early.’ It's just, let's get the job done however we can.”
On the simpler end of things, carbon capture strategies include campaigns like encouraging the restoration and proliferation of seaside habitats that suck up and sequester carbon in plants and sediment. This approach exploits the planet’s natural processes.
More complicated is something called “bioenergy with carbon capture and sequestration,” or BECCS. This involves the large-scale cultivation of plant material, which sucks up CO2 as it grows, that then gets used to produce electricity or liquid fuels. Unfortunately, all that plant cultivation demands lots of resources like water. “But more importantly, converting substantial amounts of land to energy production will probably have an impact on food prices,” says Janos Pasztor, executive director of the Carnegie Climate Geoengineering Governance Initiative, and former UN assistant secretary-general for climate change. Like what happened when rich countries went biofuel-crazy with corn and drove up prices globally. It’d be a governance nightmare.
Using direct air capture technologies to pull CO2 out of the atmosphere is even more technically complicated, and comes with different risks. But the technology is in its infancy. “The amount of R&D spending into negative emissions and atmospheric CO2 collection is extremely small,” says Steve Oldham, CEO of Carbon Engineering, which has developed a direct air capture system. “Over our 8 year existence, I think we got a total of about $10 million in funding from the Canadian and US governments.”
Carbon Engineering says its facility in British Columbia—which works by blowing air over a filter, where proprietary chemicals leach out the CO2—can suck in one ton of carbon a day. (A ton of CO2 is the equivalent of burning around 100 gallons of gas, by the way.) But direct air capture tech remains expensive because there are few incentives to develop it. The authors of the new NAS report say that at the moment, the price to operate these things is around $600 per ton of CO2. But Oldham says Carbon Engineering has gotten the price down to $100 per ton, in part by co-opting technologies in its facility from other industries like water treatment.
The problem is it’s hard to make money while trying to pull carbon from the air and sequester it back underground where it belongs. This isn’t like solar or wind power, where there’s plenty of money to be made exploiting free and abundant sources of energy.
But actually, maybe it is like the energy revolution that has cratered the cost of wind and solar power, which benefited from government subsidies. “By subsidizing, they made it possible for firms to make money producing the equipment before they were market-ready,” says Pacala, the NAS study coauthor. “So you had a whole bunch of firms competing against one another, and that system is actually really good at driving down costs.”
“We have precedence to start doing it” with NETs, Pacala adds. “It's exactly analogous. Then firms can compete with each other. You'll have everybody and his sister in Silicon Valley fighting over it.”
Quietly, the federal government has actually begun doing this. Buried in the Freedom Act is something called the 45Q rule. It provides a tax credit of $50 per ton of captured and sequestered CO2. Which, sure, isn’t much compared to Carbon Engineering’s price point of $100 per ton, and far, far away from the $600 per ton the study cites, but it’s a start.
Especially considering carbon capture would have supporters across the political spectrum. Environmentalists, of course, but even fossil fuel companies. Which, yes, is very slippery ground. “It means that if you can make climate-benign use of oil, it's a license to consume the whole resource rather than leave it in the ground,” says Pacala.
Theoretically, oil and gas giants could buy credits for sequestering the carbon equal to what their industries are releasing, making it a wash. Which would mean continuing the environmental destruction that comes with drilling and digging for resources we already have the capacity to replace with alternatives like solar and wind. It’s delaying the inevitable, when we shouldn’t put putting any carbon in the atmosphere anymore. But the backing of these powerful industries could spur development of NETs that could help solve the climate crisis.
“By itself the climate problem creates a mass extinction,” says Pacala. “By itself the climate problem creates a food crisis that could be existential for humanity. We need to solve this and solve it right now. So I think we need to hold our nose about the great being the enemy of the good.”
Alternately, governments can implement what they should have long ago: carbon taxes. The general principle is that if you release carbon, you get taxed, and that money goes toward fighting climate change. “The beauty of a carbon tax is it puts in motion so many different ways to reduce greenhouse gas emissions that we can't even predict,” says MIT economist Christopher Knittel, who studies the mechanism. “This is one of them—we don't know what the best technology is for taking carbon out of the air.”
The trouble with passing carbon taxes, though, comes right back to the fossil fuel companies. “Historically the difficulty with the carbon tax is that it in principle would penalize a bunch of very large firms that produce oil and coal, and those large firms have a large degree of lobbying power,” says Knittel. Even a blue state like Washington has tried and failed to pass a carbon tax, though that’s now on the ballot again.
That moral hazard? Yeah, it just got a lot more hazardous.
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