'Artificial trees' as a carbon capture alternative to geoengineering

Evolving technology could make cleaning the air more profitable than fouling it, say Columbia University Earth Institute scientists and a University carbon markets expert.

Many environmental journalists don’t relish their seeming role as this century’s counterpart to the Old Testament prophets proclaiming “the end is nigh.” But after hurricane Sandy, increasing numbers of Americans appear to agree with the established scientific community that increased CO₂ concentrations pose problems we need to deal with.

President Obama’s inaugural address remark that “We will respond to the threat of climate change” contrasts vividly with an America still seen throughout much of the industrialized world as analogous to the deer in the headlights: unwilling or unable to take adequate steps to avert a potential, and many would say likely, calamity.

The scientific community largely advises that while grave, the climate challenge is neither hopeless nor unsolvable. We can still prevent the worst of the projected impacts, they say, though time is of the essence. And it’s just that commodity — time — that many worry is increasingly in short supply given that global temperatures are rising and severe weather events increasing even faster than climatologists had previously predicted.

Research Actions to Match President Obama’s Words

As a world leader in science and innovation, yet one viewed by many as an obstructionist over the past decade at international conferences, the U.S. is still looked to for leadership and solutions on a challenge of such clearly global dimensions. By leading in areas such as carbon capture and sequestration, some reason, the U.S. still can measure up to President Obama’s insistence that “We cannot cede to other nations the technology that will power new jobs and new industries. We must claim its promise.”

I saw signs of America’s innovative prowess during a visit to Columbia University Earth Institute scientists Klaus Lackner and Allen Wright. The two are working on a new “carbon capture” project which involves literally sucking carbon dioxide out of the atmosphere.

The two conduct their research in a room less than half the size of most high school chemistry labs, but teeming with vials, beakers, meters, gas canisters and other devices likely unfamiliar to those not steeped in their scientific research.

The Promise of a Carbon Capture Artificial Tree

One of the tables held an array of cream-colored plastic doodads that looked like miniature shag rugs, scrub brushes and cylindrical Christmas ornaments. A smiling Lackner handed over an object shaped like the tuft of needles at the end of a pine branch. But instead of needles, they were thin streamers impregnated with sodium carbonate which chemically “mops up” CO₂ from the air.

In effect, it was a miniature prototype for an “artificial tree.” Real trees, as we learn in biology class, breathe in carbon dioxide and breathe out oxygen. The artificial tree developed by Lackner and Wright will also stand passively in the wind like a tree. But it will remove CO₂ from the air faster and at far higher levels than natural photosynthesis can accomplish. The researchers envision creating “forests” of these carbon-capturing trees to remove carbon from the atmosphere. The CO₂ can then be released by a gentle flow of water, either to be used industrially or sequestered underground.

These units, Lackner says, will be roughly the size and average production cost of a car, and collect about one ton a day of carbon from the air — the equivalent of the greenhouse gases produced by 36 automobiles in a day. Ten million of these artificial trees, he estimates, would sop up about 12 percent of the CO₂ that humans add to the atmosphere each year.

Existing methods for scrubbing carbon dioxide emitted by stationary sources like power plant smokestacks remains expensive and little used, and purging emissions remains just one-half of the carbon “capture and sequestration” challenge. Power plants account for about 41 percent of global manmade carbon emissions, with much of the rest produced by mobile sources — primarily cars, trucks and airplanes. The “artificial tree” technology is one of the first able to remove vehicular carbon emissions from the air.

An Alternative to ‘Emergency Standby’ of Geoengineering

The Columbia researchers’ approach has little in common with controversial geoengineering schemes to cool the planet, such as injecting vast quantities of sulfur dioxide into the stratosphere to deflect solar radiation, Lackner says. Geoengineering, he says, “actively interferes with the dynamics of a system which you do not understand. … It is an emergency standby which may get us through a rough decade or two, but it’s something that I’m hoping we won’t ever need to try.”

Carbon capture, by contrast, pretty much amounts to cleaning up after ourselves. “We are already putting carbon dioxide into the system,” Lackner argues. “All that I am really saying is take it back.”

To environmental activists concerned that even talk of technological fixes for global warming will discourage us from the hard work of actually cutting down on greenhouse gas emissions, Lackner insists it is indeed crucial to shift toward clean alternative energies. But we won’t get there overnight. Lackner cited the recent International Energy Agency report which says that by 2020 the U.S. will produce more petroleum than Saudi Arabia. In the face of this impending glut of cheap oil, he says, it is unrealistic to think that we won’t use at least some of it.

“Fossil fuels are not going to go away,” Lackner says. “When they criticize carbon capture, it is a bit like the fiscal cliff, they are basically saying we don’t want you to have a solution and we’d rather go over the cliff. They are telling me to fight the problem with one hand tied behind my back. … We really need all of the pieces. We will certainly need technologies to compensate for the fossil fuels that we are likely to use.”

Lackner credits his daughter, Claire, with inspiring his current line of research. As an eighth grader, Claire successfully used an aquarium pump and a solution of sodium hydroxide to take carbon dioxide out of the air. That won her first prize in the school’s science fair.

The principle is not new. Similar technologies have been used in the enclosed spaces of submarines and space shuttles to scrub the air of excess CO₂. What is novel in Lackner and Wright’s approach is mainly their outsized ambition, and the knotty technological problems which implementing it globally would entail. They are, for instance, still trying to find a cost-effective way to further purify the CO₂ after it comes off the plastic leaves, and to securely bury the gas underground or below the ocean floor.

Challenges Economic, Rather than Technical, in Nature?

Their biggest challenge, however, is not technical but economic: How to manufacture and market the artificial trees cheaply enough and in sufficient quantities to begin to make a real dent on carbon emissions. In order for this to happen, economic incentives for taking CO₂ out of the atmosphere must equal or exceed incentives currently for putting it in through the combustion of fossil fuels.

Kilimanjaro Energy, a San Francisco-based startup founded by the Columbia team to exploit their new technology, is exploring an approach for selling units to greenhouse owners whose plant growth would be stimulated by higher levels of CO₂. But even if this approach succeeds, the resulting greenhouse market would be relatively small.

For carbon capture to scale up to the point where it will be meaningful, Lackner says, governments will have to step in and create viable mechanisms for paying for it. He envisions a variant on the carbon-trading idea, with energy companies required to purchase a “certificate of sequestration” for every ton of fossil fuel they extract. The fees for those certificates would then pay for the equivalent in CO₂ remediation. “If you pump it out of the ground,” Lackner says, “you will need to take it out of the air.”

The advantage of this approach is that green technologies like solar, wind, and carbon capture would compete on a level playing field to create carbon remediation at the lowest possible cost. The best methods would be insured a healthy profit that would fund further research and development to make them even cheaper and more efficient.

Optimism on Economics of Carbon Capture

But are there ways that can make carbon capture profitable without first needing prior government action?

Graciela Chichilnisky thinks there is. The Columbia University economist is an original architect of the carbon market idea, a cornerstone of the international Kyoto Protocol, which became international law in 2005. Among the lead authors of the Intergovernmental Panel on Climate Change’s 2007 Fourth Assessment, she works from brownstone offices of Global Thermostat, a company she helped set up with Peter Eisenberger, a physicist at Columbia who was a founder of the Earth Institute.

Chichilnisky is convinced that carbon capture has to be made into a money-making proposition in its own right, and optimistic too that can happen.

Captured CO₂ can be sold, for instance, to industries for a variety of industrial and commercial uses — including, most spectacularly, reconversion into relatively clean-burning carbon-based fuels, either by feeding it to oil-extruding algae, or by combining it with the hydrogen from water by electrolysis to make methanol. Chichilnisky foresees a day when oil will be manufactured in gas stations rather than transported from well-to-refinery-to-consumer as it is now.

For now, synthesizing fuels from CO₂ would be a “marginally profitable” enterprise, Chichilnisky says, but she predicts that further research and development will lead the way to lower costs and eventually make the approach fully competitive with geological extraction. Other uses like carbonating beverages, synthesizing industrial-grade formic acid, producing dry ice, and a process called enhanced oil recovery (EOR) in which carbon dioxide is pumped into old oil wells as a solvent to scour lingering hard-to-get oil from the ground, are already promising, Chichilnisky says.

EOR currently boosts U.S. oil output by 10 percent a year. Chichilnisky predicts that the EOR market will rise to more than $800 billion over the next decade, creating a hugely enhanced demand for captured CO₂. The U.S. government estimates that state-of-the-art EOR with carbon dioxide could add 89 billion barrels of oil to the nation’s recoverable oil resources. That’s more than four times the country’s proven reserves.

With demand for CO₂, even at present levels, far outstripping supply, and companies willing to pay $100 a ton to get a hold of it, the business prospects for carbon capture look bright.

Some companies have already begun investing in this emerging technology. The California-based Global Thermostat, for instance, has set up a demonstration carbon capture plant at the Stanford Research Institute in Menlo Park. The 30-foot-high honeycomb structure captures more than two tons of carbon a day from the surrounding air. The system requires relatively low levels of heat to release the captured CO₂ from the sorbent, with which it chemically bonds. Chichilnisky sees real advantages to this approach, because it means the units can be located in places like power plants, aluminum smelters, and other industrial facilities that produce large amounts of residual process-heat.

A power plant equipped with a carbon capture unit could potentially become “carbon negative,” she says. That is to say, it could take out of the air more than twice the carbon it puts in using only the heat that the plant itself creates. Not only would it take the CO₂ out of the flue gases in the plant’s smokestack, but it would remove the gas from the ambient air too.

“This reverses the paradigm that links fossil-fuel power production with carbon emissions,” Chichilnisky says. And because of the efficiencies of the process that uses waste energy, the cost of CO₂ production could be as low as $10 to $20 a ton, she estimates. (Compare this to what big beverage manufacturers like Coca Cola and Pepsi currently pay — about $200 a ton for the fizzy gas.)

Another place where the carbon capture units might be a boon is on oilfields that employ EOR. Producing the needed CO₂ in situ would eliminate the high cost of transporting the gas via pipelines.

Ramping Up … ‘Right Place at Right Time’

Professor Chichilnisky prophecies that this evolving technology is primed to “turn the world economy on its head,” making cleaning the air more profitable than fouling it.

The challenge now has to do with figuring out how to ramp up carbon capture to levels where it would begin to put a brake on human-created climate change.

“We will need to build thousands of such plants each one capturing millions of tons of CO₂ per year,” Chichilnisky says. “We have to accelerate the technology because this is the moment of truth, possibly the moment-of-no-return if we don’t act now.”

While she sees market forces driving much of the growth of carbon capture, Chichilnisky says that the push must be “enhanced, facilitated, speeded up by the carbon market” in which industries are required to pay for their carbon emissions by funding equivalent efforts dedicated to remediation. The carrot of profits from innovative carbon capture technologies, together with the stick of penalties for fouling the air, will convince carbon emitters that they need to clean up their act.

How long will this take? Ten to 20 years minimum, says Chichilnisky. “Our solution is not going to be here tomorrow morning,” she says. “But we expect to succeed beautifully because the carbon market is spreading, and even before you apply the carbon market, our technology is profitable, and it works. … And all of the carbon capture technology that we are talking about is in the U.S. It is almost a contradiction, the U.S. politically is resistant to change, my God, there are people who don’t even believe in evolution. But the big scientists are here, and the most advanced innovation is here. We are in the right place at the right time and we just have to make it happen.”

AUTHOR
Richard Schiffman is a freelance environmental journalist living in New York. This article is adapted, with permission, from the version originally published in Earth Island Journal.