Sucking CO2 From Air Is Cheaper Than Scientists Thought (technologyreview.com)

An anonymous reader quotes a report from MIT Technology Review: While avoiding the worst dangers of climate change will likely require sucking carbon dioxide out of the sky, prominent scientists have long dismissed such technologies as far too expensive. But a detailed new analysis published today in the journal Joule finds that direct air capture may be practical after all. The study concludes it would cost between $94 and $232 per ton of captured carbon dioxide, if existing technologies were implemented on a commercial scale. One earlier estimate, published in Proceedings of the National Academies, put that figure at more than $1,000 (though the calculations were made on what's known as an avoided-cost basis, which would add about 10 percent to the new study's figures). Crucially, the lowest-cost design, optimized to produce and sell alternative fuels made from the captured carbon dioxide, could already be profitable with existing public policies in certain markets. The higher cost estimates are for plants that would deliver compressed carbon dioxide for permanent underground storage. David Keith, a Harvard physics professor and lead author of the paper, is also the founder of Carbon Engineering, "a Calgary-based startup that has spent the last nine years designing, refining, and testing a direct air capture pilot plant in Squamish, B.C.," reports MIT. "Carbon Engineering plans to combine the carbon captured at its plants with hydrogen to produce carbon-neutral synthetic fuels, a process the pilot facility has already been performing." The company has secured $30 million, but is seeking additional funds to build a larger facility that will begin selling fuels. CNBC notes that Carbon Engineering is owned by several private investors, including Bill Gates.

Comments

Now we know.

[Gravis Zero]

Now that we know how much it should cost to remove CO2 from the sky, we should begin taxing corporations and products that release CO2 in the atmosphere. The money would then be used to pay other corporations to capture CO2 from the atmosphere.

There has been a long history of using environmental capital without consequence and that needs to come to an end if we're going to save this planet.

Re:Now we know.

[thomst]

Gravis Zero opined:

There has been a long history of using environmental capital without consequence and that needs to come to an end if we're going to save this planet.

While I agree completely with the first clause of this statement, the second half (which needs a comma after "and," btw) is a popular cliché that never fails to make me groan in frustration.

The Earth will be fine, regardless of whether we, as a species, manage to solve the slow-motion environmental catastrophe we accidentally created. What's at risk is the current ecosystem to which we're accustomed, including most of the extant species of multi-cellular life.

About 250 million years ago, give or take a million years or so, something very similar to what we've set in motion happened to the Earth. In what's known as the Permian-Triassic Extinction event, carbon dioxide levels rose to much higher levels than they are today, for reaons we still don't fully understand. As a result, the global temperature increased by about 10 degrees Centigrade, and the icecaps melted, releasing large amounts of methane from rotting plant life that had been buried under glaciers during the ice age that began the global extinction event. Methane clathrates in the deepest, coldest parts of the ocean (there was only one, at the time) also melted, releasing a whole lot more methane, and turning the ocean into a kind of anoxic fizzy.

In the ocean, 96% of species went extinct. On land, 70% of multi-cellular species disappeared. The entire ecosystem collapsed within about 100,000 years. The P-T extinction event was so severe, that it's often referred to as the "Great Dying." It was so devastating that it took between 4 and 9 million years before the global ecosystem recovered sufficiently for new species to begin to fill the niches the global warming event had created.

But recover it did - and the result was the beginning (in the Triassic Period) of what eventually (in the Jurassic and Cretaceous) became the Age of Dinosaurs. By the time the Chixiculub bolide smacked into the coast of what is now the Yucatán Penninsula in southern Mexico, about 65 million years ago, the dinosaurian Ornithischia, Sauropodomorpha, and Theropoda taxa had dominated the planetary ecosystem for approximetely 120 million years.

And they thrived in the elevated temperatures the Permian-Triassic extinction event created. Once the excess CO2 cleared from the ocean, speciation rapidly filled it with a dizzying variety of fish, invertebrates, plant life - and dinosaurs. From viruses and bacteria to insects and arachnids to grasses, shrubs, and trees to animals of all sizes, the planet teemed with life within a few tens of millions of years after the most devastating extinction event in its history. (Okay, arguably the Oxygen Catastrophe might have caused an even more comprehensive extinction event - but we can't really determine whether that was the case, because, in those earliest days of life on Earth, no species had developed shells or exo- or endo-skeletons, so they didn't leave a fossil record for us to read.)

As evidenced by the eventual recovery from the P-T Extinction, the popular meme of "saving the planet" is hyperbole of the most narcissisitic stripe. The planet - and life itself - will survive the extinction event we have already caused (and will continue to cause for several thousand years to come). Our contemporary varieties of megafauna are almost certainly all doomed (with the possible exception of some familiar commensal and chattel species - I suspect dogs and cats, for instance, will survive as long as humans do). However, you can say "goodbye" to the whales and dolphins, the lions and tigers and bears, the el

Re:Now we know.

[Solandri]

Gasoline generates about 8.89 kg of CO2 per gallon. So producing 1 ton of CO2 would require burning (1000 kg)/(8.89 kg/gallon) = 112.5 gallons of gasoline. The current average price of gasoline is $2.934/gallon, so 112.5 gallons of gas would cost (112.5 gal)*($2.934/gal) = $330.

A $100-$200 surcharge per ton of CO2 would thus raise the price of gasoline by just 30%-61%.

Using the same EIA chart, coal generates roughly 2 tons of CO2 per ton of coal. One ton of coal contains roughly 24 Gigajoules of thermal energy, which is 6.67 MWh. If the coal plant is 40% efficient, that means that one ton of coal generates 2.67 MWh of electricity. Since that one ton of coal also emits 2 tons of CO2, we end up with (2 tons CO2) / (2.67 MWh) = 0.75 tons per MWh.

Natural gas generates roughly 53.12 kg of CO2 per thousand cubic feet. A thousand cubic feet of methane contains 1.037 million BTUs of thermal energy = 303.9 kWh. If the gas plant is 60% efficient, this means 53.12 kg of CO2 are emitted per 182.3 kWh, or (0.053 tons CO2) / (0.1823 MWh) = 0.29 tons per MWh.

Coal accounts for 30.1% of U.S. electricity. Natural gas accounts for 31.7%. So the fractional CO2 contribution of these fossil fuels to electricity is (0.75 tons/MWh)*(0.301)+(0.29 tons/MWh)*(0.317) = 0.318 tons of CO2 per MWh. A $100-$200 surcharge per ton of CO2 then ends up costing $31.80-$63.60 per MWh, or 3.2 cents - 6.4 cents per kWh.

Average electricity price in the U.S. is 12 cents/kWh. So a $100-$200 surcharge per ton of CO2 would raise the price of electricity by 27%-53%. Almost exactly the same percentage as gasoline.

Like I keep trying to explain to people: Electric vehicles aren't cheap to operate because they're more energy efficient. They use nearly as much energy as ICE vehicles. They're just cheaper to operate because the coal and natural gas used to generate electricity are roughly an order of magnitude cheaper per MJ than gasoline. If you want to reduce CO2 emissions, buying an EV presently doesn't help. When you replace an ICE vehicleswith an EV without changing the makeup of your electricity sources, all you've done is shift your CO2 emissions from the car's tailpipe to a fossil fuel power plant's smokestack. That's why the claim that EVs are "zero emissions" is BS at present. You need to replace fossil fuel power plants with nuclear and renewable plants to cause a reduction in CO2 emissions.

Re:Now we know.

[K. S. Kyosuke]

An electric car can use something like 0.2 kWh/km. Let's say you drive 20000 km per year. That's around 4000 kWh of electricity per year. At a mediocre 0.15 capacity factor, that's the average output of a 4 kW array or so. Costs around $5000 where I live.

even with tracked arrays, you can collect for a maximum of around 8 hours a day with any efficiency, so you will need 3.5Kw of solar source over your 8 hours. Doesnt sound too bad does it? not figure in practical Solar load factor, around 20%, so you need 17.5 Kw of solar cells.

That's double accounting. The capacity factor already includes the fact that you don't have 24h of maximum output. Your 17.5 kW array with a 0.2 capacity factor generates almost 600 kWh per week on average, which is the of triple your requirement - not surprisingly the factor of three you mistakenly added in "you can collect for a maximum of around 8 hours a day with any efficiency".

I saw this at least 3 years ago from US Navy

[blindseer]

Here's a 3 year old video on a US Navy project doing this same thing. https://www.youtube.com/watch?...

This Navy project is not new but they have people on the project go around to conventions and such to speak on it. They show good economics, being able to convert CO2 and hydrogen from any natural water source into a liquid fuel for aircraft and other uses. All they need is some funding to ramp this up to something that actually produces fuel for military aircraft.

The largest consumer of fuel in the USA is the US Air Force. The largest air force in the world is the US Air Force. The second largest air force in the world is the US Navy. The third largest air force in the world is the US Marine Corps. If we can get the US military to use the technology that they already have to produce jet fuel then that would be a major win in so many ways.

This idea of carbon neutral fuel production is dependent on a carbon neutral energy source. We have this carbon neutral energy source in nuclear power. The US Navy knows how to operate nuclear power safely. The US Coast Guard is desperate for some new ice breakers, let them have them and make them nuclear powered. Making more nuclear powered US Navy and US Coast Guard surface ships, and this fuel synthesis process to fuel the support aircraft and auxiliary boats, means a big dent in consumed petroleum. Add in some nuclear power on shore to power airports and military bases, and make the fuel for the vehicles that come and go, and that's another big dent in petroleum consumed.

Electricity might work for cars and trains but that won't work for boats and planes. A large enough ship can be nuclear powered, and we should embrace that wholeheartedly for military and civilian ships. Planes won't fly without kerosene. We now get kerosene from digging it up from the ground but we can get it from seawater if we just develop the technology and take the problems of digging up petroleum seriously.

I can't take anyone seriously on the threat of global warming if they do not include nuclear power in the solution. They mention this great process of pulling carbon from the air to turn into fuel but say nothing of where the energy to power it comes from. That says a lot to me. They can't bring themselves to admit that nuclear power is necessary to make this viable. The US Navy has no such aversion to nuclear power. We can at least allow the US Navy to develop the technology they have. Like so many things the US military develops it is likely to find its way into the civilian market in time.

Re:one trillion dollar is a bargain!

[dgatwood]

The dollar price is a poor metric. We should really be looking at energy requirements, especially the ratio between energy produced per ton of CO2, and the energy required to pull it back from the air.

This. Without violating one or both of the laws of thermodynamics, it seems almost certain that any sort of sequestration cannot produce more energy in the form of fuel than it uses as input. After all, you're going from a state that has already reacted with oxygen to a state that will release energy when it burns in oxygen, which means that you have to add energy to get it back to such a high-energy state.

So where is all of that energy going to come from? My best guess would be burning fossil fuels. And thus, the cycle of infeasibility is complete. Either that or this sequestration will consume something else that is in a high-energy state and produce something else in a low-energy state, in which case we can do this, but only until we run out of the required reactant. I'm not holding my breath on that one, though.

Of course, if we somehow manage to get to a point where we can produce all of our energy needs without burning fossil fuels, then I suppose sequestering CO2 into gasoline might become feasible. Then again, if we get to that point, we won't need this technique, because plants will take care of reducing the CO2 for us, and we won't need the fuel that results from it. So I'm failing to see how such a solution could ever be practical or economically viable in any sane universe.

Then again, the theory that CO2 isn't a problem seems to be supported by the U.S. right-wing political establishment, and they have given us a President who seems to think that he is above the law, so maybe he's above the laws of thermodynamics, too.

*shrugs*

Skims paper

Holy crap. I was right. They are talking about burning fossil fuels to make fossil fuels. *sobs uncontrollably* But I don't see anything about producing fuel in the actual article, beyond a passing mention that if someone wanted to come up with a way to create fossil fuels in a carbon-neutral way, they would need to start with carbon. As far as this paper is concerned, they're sticking it in a tank, which is a lot more plausible than doing something useful with it.

The big problem, then, is that there's not likely to ever be any monetary upside to capturing the carbon, and if you do it with natural gas, you only capture about twice as much CO2 as you put out. About 56.1 kg of CO2 are emitted for every gigajoule of CO2 that you burn. If powered by natural gas, this design burns 8.81 GJ of nat gas per metric ton sequestered. That's almost half a metric ton of CO2 emitted per ton of CO2 sequestered, plus about 202 kg of H2O, for a grand total of 696 kg of greenhouse gases for every 1000 sequestered, or only about 44% more sequestration by mass than you emit to produce the power.

And in the end, you have a bunch of tanks of CO2 that nobody wants. Also, this is a net consumer of water (because some of it evaporates). Want to know what's even more precious than energy these days? Fresh water.

I just don't see it, unless they can find a way to turn it into carbon credits or something.

Re:$92-$234 too cheap...

[AmiMoJo]

I hear this all the time, "We can't use nuclear power, it's too expensive." What of solar power? What do people have to say about that? "We have to subsidize solar power so we can develop the technology and make it cheaper than coal." Okay then, why not subsidize nuclear power so we can develop the technology until it is cheaper than coal?

The total cost per megawatt of nuclear is about double solar/offshore wind + battery storage.

That's the real cost. Subsidies are only used to make them commercially viable alternatives to coal.

What you are proposing is guaranteed high subsidies for many decades, and a bunch of unknown costs because we are sure to find new safety issues and haven't figured out what to do with the waste yet. Alternatively, we have some temporary subsidies on a clean form of energy that will become the cheapest form of generation ever (cheaper than subsidised coal) within a few decades at most.