This article originally appeared on the Leonardo DiCaprio Foundation website. It’s being reprinted here as CleanTechnica releases the case study on Carbon Engineering’s air-to-fuel and enhanced oil recovery technology.
Promoted by numerous attention-grabbing headlines of late, the technology called air-carbon capture (ACC) is having a moment in the sun. But all the hype is encountering dark clouds of technical and economic viability, not to mention poor environmental outcomes.
One Canada-based company, Carbon Engineering (CE), has been lauded as the future of air-carbon capture. They recently received $68 million in funding, most of it coming from a handful of wealthy investors and three major fossil fuel companies — Chevon, Occidental, and BHP.
Air-carbon capture as a climate solution is based upon an extremely challenging technical proposition: separate out the very diffuse carbon dioxide gas mixed into the air we breathe and capture it using a variety of technologies or biological processes. This would be done at much faster rates than the Earth’s carbon cycle would remove and sequester if left alone. As you can imagine, this would require vast amounts of energy.
CE’s solution would require the equivalent natural gas use of 70,000 Canadian homes for one year just to capture 1 million tons of CO2. Capturing that 1 million tons would require a wall of fans — 65 feet high, 25 feet thick, and 2 kilometers long — running 24/7 without interruption for 365 days. Its operation would create half a million tonnes of new CO2 from burning the fossil fuels to power the technology.
The company claims that they are using all this carbon to make replacement synthetic fuels. But a gallon of this fuel would cost 18–25 times more and have 22–35 the CO2e emissions as just using electricity in an electric vehicle. The CO2 emissions would be a third those of normal gasoline, but the cost would be roughly three times as much as the US average.
If the roughly $80 million CE has received to date were used to build a wind farm, a 40 MW facility of 16 2.5 MW wind turbines could have been built. The electricity from that wind farm would enable about 35,000 Tesla Model S or X cars to drive the average distance traveled by US drivers annually.
For freight trucking, you could travel 4 times as far for a fifth the CO2 emissions and well under half the cost in an electric truck as in one fuelled by a synthetic diesel from Carbon Engineering. The only viable market is to enable fossil fuel companies to pump more oil.
There are about 3,200 billion metric tons of CO2 in the atmosphere and about 1,250 billion of those metric tons have been added by us since the beginning of the Industrial Revolution. While those are very big numbers, the CO2 is only 415 parts per million of the atmosphere. If it were a single layer, it would be a 41 meter thick blanket covering the Earth, but it’s spread through about 100 kilometers of atmosphere.
Carbon Engineering is a Squamish, BC-based air-carbon capture company. It’s the reason why many are paying greater attention to the approach, as they received $68 million USD in funding recently. And much of that funding comes from three fossil fuel majors: Chevron, Occidental, and BHP.
All of the technical processes for air-carbon removal stumble over the first issue, which is that there isn’t a lot of CO2 in any given cubic meter of air, so you have to find a way to move a lot of air through a small space or move a lot material through a lot of air. Both involve a great deal of energy to do in any speedy manner. Then they run into the second problem, which is that anything that binds with CO2 from the air is hard to break apart, requiring a lot more energy, usually in the form of heat.
Carbon Engineering’s approach to this large energy requirement is to use 5.25–8.81 gigajoules of natural gas per ton of CO2 captured from the air. That’s a month to a month-and-a-half’s supply for the average Canadian home.
The company talks about the low-carbon electricity in BC which they use for a subset of their process, but really, it’s a big natural gas consumer. And as BC has among the lowest carbon grids in the world, every other jurisdiction where it was deployed would have a higher carbon load.
Even with BC’s low grid emissions, Mark Z. Jacobson of Stanford University calculates the total carbon debt of Carbon Engineering’s technology, both upstream and for processing, is 73% of each ton of CO2 captured.
Then come the follow-on problems, which are that CO2 is a low-priced commodity requiring significant pressurization, is expensive to ship to where it is sequestered or used, and has few markets. The first two add more energy and carbon debt to every ton of CO2, but it’s the market issue which is the real concern.
The majority of carbon sequestration done to date has involved pumping CO2 into tapped out oil wells, where the CO2 makes the oil easier to pump out. Every ton of CO2 put underground results in about a quarter of a ton of oil coming back up. And as oil is burned it turns into CO2, about 3.2 times as much by mass. Every ton of CO2 put underground, in other words, results in about 0.8 tons of CO2 in the air. That sounds like a net win, except that Carbon Engineering’s process is already 50% to 73% new CO2, depending on how far upstream you count. That means that any oil brought up is still adding net CO2 to the atmosphere.
Enhanced oil recovery is certainly one of the reasons why Occidental Petroleum invested in the company. The two firms have just announced a Permian Basin air-carbon capture facility that will be used for enhanced oil recovery.
As Jacobson points out, air-carbon capture will always have worse results than spending the same money on displacing fossil fuel usage entirely with mostly wind and solar generation. Even if it were fully carbon neutral, we would still have the other challenges of fossil fuels, such as water and air pollution. The $80 million in total funding Carbon Engineering has received to date could have built a 40 MW wind farm which would generate about 150 GWh of low-carbon electricity every year, electricity which per study after study displaces fossil fuel generation and resultant CO2 emissions and pollution on a 1:1 ratio.
Researching air-carbon capture for use post-2050 remains a very good means of establishing the intellectual capital and basic technologies for when it makes sense to use them. But attempts to commercialize them today are premature, and glowing headlines about solutions enable fossil fuel concerns to stick with business as usual for longer. Soil carbon capture approaches have more upsides and are mostly more operational in nature, and are worth pursuing.
This exclusive CleanTechnica report is available now. It is core information for policymakers, investors, and educators on this poor but heavily promoted wedge in the necessary battle against climate change.
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