Making fuel from air and water

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We can and do recycle all sorts of things. Paper, plastic, glass (OK, that last one not so much right now), Christmas fruitcakes…the list goes on and on.

Wouldn’t it be great if we could also recycle the hydrocarbons we burn as fuel? Imagine if you could somehow take the carbon dioxide out of the air, recombine it with hydrogen, and produce new fuels. You could lessen the need for oil and slow the build-up of carbon dioxide in the atmosphere at the same time.

It sounds like wishful thinking—but scientists at Los Alamos National Laboratory say they can do it.

Called Green Freedom, their technology is built on a new process for extracting carbon dioxide from the atmosphere. Combine that carbon dioxide with hydrogen created by splitting water into hydrogen and oxygen, and you can create sulfur-free synthetic fuels and organic chemicals.

The technology involved is new, but it’s not radical. According to the researchers, led by Dr. F. Jeffrey Martin and Dr. William L. Kubic, Jr., it’s based on “modest, but novel, extensions of current technologies that are in wide use.”

It’s not hard to capture carbon dioxide from the atmosphere. As Martin and Kubic point out in their concept paper (which is freely available online) carbon dioxide is readily absorbed into a potassium carbonate solution. However, carbon dioxide in the atmosphere is very dilute, at about 370 parts per million, so capturing and recovering it in commercially significant quantities is a challenge. That’s the challenge that the Green Freedom scientists say they’ve overcome.

Their new process also drastically reduces the energy required, key to making the whole scheme practical. “The new stripping process requires (approximately) 96 percent less energy than a conventional thermal-stripping process,” they note, and add that new materials are emerging that would reduce the capital cost of the necessary equipment below what they assumed in their analysis.

The hydrogen that must then be combined with the carbon dioxide to produce fuel can come from any existing hydrogen-producing process. The concept paper refers to the water electrolysis process because that’s the lowest risk technologically: we already know how to get hydrogen by passing an electrical current through water.

Note that you’re not getting something for nothing here. All of this technology requires energy. To keep the whole process carbon-neutral, that energy has to come from a power source that doesn’t produce any carbon dioxide itself. The researchers being from Los Alamos, it’s probably not surprising they suggest using nuclear power. However, they note that wind power, hydroelectric power or solar power could also be used if they’re economically competitive.

Of course, there’s not much point in producing fuel if that fuel costs so much no one will buy it. Martin and Kubic attempt to calculate the cost of a U.S. gallon of methanol produced by a Green Freedom plant and a U.S. gallon of gasoline, both produced using existing and well-established fuel synthesis methods.

They figured in estimated capital costs, assumed the plant would be nuclear powered, figured in a profit margin, and came up with an at-the-pump price for their synthesized gasoline of $4.60 a gallon (that’s $1.21 a litre in Canadian terms, if you figure the U.S. and Canadian dollars at par, and these days, you can!), and the price of synthesized methanol at $1.65 a gallon.

Expected improvements in technology could reduce the price of gasoline at the pump to just $3.40 a gallon (89.5 cents a litre) and the price of methanol to just $1.14 a gallon, and that could fall further with additional technological achievements.

The researchers know this sound almost too good to be true. They conclude: “Making gasoline from air and water sounds exotic, but now practical technology has been developed to implement known chemical pathways for producing fuel from these abundant raw materials.”

There are uncertainties about capital and operating costs, of course, and further research is planned.

But it Green Freedom pans out, it will certainly be, as Los Alamos National Laboratory calls it, “transformational.”

My own modest suggestion: paint the plants bright blue, with a recycling symbol in white on the side.

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