New Uses for Carbon Dioxide Get Spotlights at ARPA-E Energy Summit

Decreasing our carbon footprint—most of us who recognize the dangers posed by climate change make that a priority. But some alternative-energy engineers are taking a slightly different view. Instead of simply reducing the carbon dioxide around us, they are finding ways to channel it by using it to create clean energy. Their methods for carbon "recycling" went on exhibit at the Department of Energy’s ARPA-E Energy Innovation Summit that ran from Feb. 27-29 at the Gaylord National Hotel in the National Harbor, Maryland.

The event showcased hundreds of novel approaches to better renewable energy and energy efficiency. Every project was on display by virtue of having won a grant from the U.S. Department of Energy’s ARPA-E (Advanced Research Projects Agency—Energy) division.

Biofuels from Carbon Dioxide

A Columbia University team derives liquid fuel by feeding carbon dioxide and ammonia to bacteria inside a tank. The bacteria ingest both, metabolize them, and secrete liquid wastes that the team extracts. The extracted liquids are a usable fuel. The bacteria also secrete nitrites that, with electricity applied to them, convert back into ammonia. The whole process is thus self-sustaining.

The process draws carbon dioxide from the air, unlike fossil-fuel generation, which pulls carbon dioxide up out of the ground. The difference is crucial. It means that this process could generate electricity by using existing atmospheric carbon dioxide and without adding any new carbon dioxide to it.

“We’re taking the carbon that we already have and recycling it,” said Scott Banta, a Columbia chemical-engineering professor directing the project.

Designing New Organisms

The quantities of fuel that Banta et al.’s bacteria produce are, unfortunately, pretty small. But Banta hopes that with genetic modifications, they could secrete more fuel more quickly. Luckily, Ginkgo Bioworks is trying to do just that. This upstart bioengineering company cultivates microbes for use by industrial and research firms. It is currently developing a bacterial strain that consumes carbon dioxide and produces transportation fuel, and another microbial strain that makes fuel following digestion of hydrogen sulfide (a waste product that petroleum refineries belch out in huge quantities).

Ginkgo Bioworks has not drawn a lot of business yet. But Curt Fischer, cofounder, said that with the $8 million grant that the company got this year from ARPA-E, it will be able to grow more microbe cultures and run tests to prove that they do what they are supposed to do. This will win it more credibility and, Fischer hopes, more clientele.

Electrically Charged Bacteria

Genetic modification is one way to increase a bacterial culture’s fuel production. Applying electrical charges to the bacteria is another. A team from Harvard University’s Wyss Institute for Biologically Inspired Engineering is trying the latter.

According to Joseph Torelli, a project researcher, electricity is really just streams of electrons. If bacteria receive low voltages of it, they safely ingest the electrons and use them to break down carbon dioxide from the air into the fatty acids and other vital compounds. The human researchers extract some of those fatty acids and can use them as a viable fuel.

It is the same metabolic process that bacteria undergo all the time, only on an accelerated scale. Natural microbial metabolism, without the electrical jumpstart, is too inefficient, according to project researcher Matthew Mattozzi. He cited algae cultures that some human growers cultivate to derive biofuels. Solar panels are, square foot for square foot, 15 times as efficient.

“Since solar panels are more efficient than microbes, why not make a hybrid that uses both?” Mattozzi said, explaining that the initial electricity could come from solar panels. And unlike solar panels, which only produce electricity, the end result is a liquid fuel.

Where Will the Energy Chips Fall?

ARPA-E, which the Obama administration formed in 2009, awards grants every year to fledgling alternative-energy and energy-efficiency projects. Many of these projects have a hard time securing private investment capital: Because they are so novel and experimental, no private investor can be certain that they will succeed and deliver a return on investment.

They are, in essence, a public gamble. And the Department of Energy takes flak for this from
critics who urge the government to leave it to the free market to pick renewable-energy winners and losers. They hold that chancing taxpayer dollars on novel technologies whose viability is uncertain is needlessly risky and wasteful.

But is there a better alternative? Consider the energy crisis that lies ahead of us: energy demands projected to skyrocket while fossil-fuel reserves everywhere are projected to peak, all while present fossil-fuel use damages human health, natural ecosystems, and the Earth’s climate. It is no exaggeration to say that human welfare and the long-term continued functioning of the world’s economies are on borrowed time and count on us finding sustainable energy alternatives soon.

Would it be better that the U.S. government sit passively in hopes that the market might spontaneously toss forth a solution? Should it do nothing as a dire energy situation threatens to engulf the world’s peoples, economies, and infrastructures? The government does not leave it to market forces to develop military weapons technology. Nor did it trust in free enterprise to launch a lunar mission, build space shuttles, or construct an International Space Station. Why then, should the government urge laissez-faire on the matter of energy supply?

As with anything else in life, to not try is to guarantee failure. Let future generations be able to say that our society and governments made every effort to solve the energy crisis. Let us pull out every stop and invest in every effort. If a few efforts founder, so be it. Many others will succeed. And some will succeed beyond all measure. Funding ARPA-E’s fledgling projects is no taxpayer waste. It is an investment in the human will to innovate and improve. That will carried human astronauts to the Moon. It can, if we let it, carry human civilization to a sustainable energy future.