Sustainable Energy

Grasping for Ways to Capture Carbon Dioxide on the Cheap

Wind and solar get all the attention, but a key path to lowering emissions involves finding a less expensive way to do carbon capture.

Carbon capture could be key to lowering greenhouse emissions.

Last week, the new U.S. secretary of energy, Ernest Moniz, pledged to continue his predecessor’s work in making the Department of Energy a “center of innovation,” while also highlighting projects he thought deserved more attention. Near the top of his list is a renewed emphasis on carbon dioxide capture and storage (CCS), a technology that could prove vital to combating climate change, but is developing far too slowly, according to the International Energy Agency.

Moniz will face the challenge of moving forward with CCS in a time of tight budgets, in contrast to the fat years enjoyed by former secretary Steven Chu as a result of the tens of billions of dollars allocated to the agency via the Recovery Act of 2009. Despite that challenge, CCS is considered so important for reducing greenhouse gas emissions that technologists are looking for cheaper ways to develop it.

Some researchers have already found ways to do large-scale demonstrations at a fraction of the originally proposed costs. They’re also planning to defray costs by selling captured carbon dioxide to oil producers, who will use it to force recalcitrant oil out of wells. For the longer term, they’re developing new technologies that could greatly reduce the cost of capturing carbon dioxide (see “Fuel Cells Could Offer Cheap Carbon-Dioxide Storage” and “Novel Power Plants Could Clean Up Coal”).

CCS technology already gets far less attention and funding than solar and wind power (see “Will Carbon Capture Be Ready on Time?”). In the U.S., solar power and wind technology get as much funding in a year as CCS does in 10—and that includes a one-time infusion of billions of dollars from the Recovery Act, estimates Howard Herzog, senior research engineer at the MIT Energy Initiative, which Moniz headed before he became energy secretary. But this doesn’t reflect the crucial role CCS could play in reducing greenhouse gases. If governments ever enact strict limits on carbon dioxide emissions, CCS could make complying with those regulations much cheaper, Herzog says.

In fact, electricity generation from coal is expected to grow twice as much as generation from renewable energy by 2020. Without CCS, many coal plants would have to be shut down to meet strict regulations. CCS would make it possible to continue using relatively cheap fossil fuels, and it could reduce carbon dioxide emissions at a lower cost per ton than some other technologies. “People are reluctant to have a climate policy because of the price,” Herzog says. “If you take CCS out of the loop, you increase the price.”

The problem is that no one knows how much CCS will cost at a large scale, and to find out will require large-scale demonstrations that will cost billions of dollars each.

One workaround is to find cheaper ways to demonstrate the technology at a large scale. The FutureGen project in the United States has been talked about for years—originally as a massive new kind of power plant that would produce hydrogen and electricity (see “The Future of Clean Coal”). The project’s high costs led the Bush administration to shut it down, but it was reinstated in a cheaper form after the Recovery Act. The project now involves retrofitting an existing power plant, and is expected to cost about half as much. But even with that change, there’s a chance the project won’t be ready in time to cash in on funds from the Recovery Act of 2009, given the challenges in designing and permitting the project, Herzog says. He gives similarly low odds of success for a handful of other power plant CCS projects that would be eligible for Recovery Act funds if they reached certain milestones on time.

Another way forward could be to perform carbon capture not at power plants, but at sources that produce a more concentrated stream of carbon dioxide, such as natural gas production facilities. This has been done for years at a natural gas facility in Norway.

And progress is being made on capturing carbon dioxide at industrial facilities in the United States. Two of three such projects—one that captures carbon dioxide from fermentation at an ethanol plant, and another that captures it from a hydrogen production plant—are now operational. Such projects will account for about half of the carbon dioxide captured using CCS by 2050, according to the International Energy Agency. Indeed, CCS might be the only way to deal with emissions from sources such as ethanol plants and steel plants. “It’s a solution for many areas where no, or very few, other solutions exist,” says Juho Lipponen, head of the CCS Technology unit at the International Energy Agency.

Selling the carbon dioxide for use in oil recovery could also help move CCS technology forward, says John Thompson, director of the Fossil Transition Project at the nonprofit Clean Air Task Force. Oil producers can afford to pay for carbon dioxide captured from some industrial processes, and after the oil producers are finished producing oil, they can cap the well and trap carbon dioxide underground.

But the oil recovery market has its limits, and oil producers won’t pay enough for carbon dioxide to completely offset the cost of capturing it from power plants, Thompson says. But it could be enough to make carbon capture commercially viable, especially if it’s combined with a tax credit like the one given to wind farm operators.

Selling carbon to oil companies could have another, less welcome effect. By increasing oil production, it could lead to more oil consumption and thus more carbon dioxide emissions. So to reach the scale needed to make a substantial dent in carbon dioxide emissions will require other ways to store the carbon dioxide—such as in porous saltwater aquifers.

Ultimately, CCS will make a real dent in carbon emissions only if a price is placed on carbon dioxide through regulations, Herzog says. But ongoing efforts could help lower costs and make the technology seem more viable.

As Moniz said last week, “Lowering the cost of low carbon technology is going to be a tremendous facilitator for the policy agenda going forward.”

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