Carbon Sequestration: Too Little, Too Late?
To impede climate change, scientific studies suggest, billions of tons of carbon dioxide need to be captured from hundreds of fossil-fuel power plants in the next few decades—and as soon as possible. Without large-scale carbon capture and sequestration (CCS), other measures—including rollouts of renewable and nuclear power—will not avert catastrophic climate effects in the coming century and beyond (see “The Carbon Capture Conundrum”).
CCS technologies are getting more sophisticated and efficient, and a few full-scale projects are going online. At the same time, researchers warned last week in Austin, Texas, at the world’s largest conference on CCS that the technology remains economically practical in only a few situations.
The most significant recent advance was the opening of a 110-megawatt coal power and CCS plant in Saskatchewan, called Boundary Dam, built by the provincial utility SaskPower (see “In a First, Commercial Coal Plant Buries Its CO2”). Michael Monea, president of SaskPower’s carbon capture and storage initiatives, spoke with almost religious fervor at the conference about the project, which will capture 90 percent of its carbon dioxide. “Build more of them, build them bigger, and it will have an effect on the world—I believe that,” he said.
That plant will use the CO2 it captures to help push more oil out of the ground, a process called enhanced oil recovery, or EOR. The sale of the carbon dioxide for EOR is a key mechanism to financing early CCS projects, but this application of carbon burial tends to perpetuate the problem.
“We’re lucky we have these commercial units at all,” says Gary Rochelle, a chemical engineer at the University of Texas, Austin, who is working on a carbon capture project at a coal plant south of Houston. “A few folks have stepped out and are taking risks, and EOR enables them to do it.”
CCS imposes big capital costs and energy penalties: the Saskatchewan plant’s CCS unit cost $800 million to build and consumes 21 percent of the coal plant’s power output in order to scrub out the carbon dioxide and compress it into a liquid for burial. Yet the work of Rochelle and others has steadily reduced the energy required to do this, and they are developing numerous new ways of removing carbon dioxide. Monea added that thanks to lessons learned from the pioneering facility, “the next carbon capture plant could be built for 20 percent to 30 percent less.”
China and the United States are responsible for about half of the world’s greenhouse gas emissions. While China has no commercial-scale CCS projects, like other nations it has several pilot projects under way. In the United States, a handful of projects of significant scale are nearing completion, including ones in Port Arthur, Texas, and Mobile, Alabama. The largest of the four is a 565-megawatt coal and CCS plant in Kemper, Mississippi. It is similar to Boundary Dam but is five times larger, and is nearing completion at nearly double its projected $2.5 billion cost. It will also use the carbon dioxide for oil recovery.
Some sort of policy that would put a price on carbon emissions seems to be needed to drive CCS forward. Nothing is forcing the fossil-fuel industry’s hand, and the coal industry is loath to see more costs imposed on its product.
Despite the inertia, Julio Friedmann, a deputy assistant secretary for clean coal in the Office of Fossil Energy at the U.S. Department of Energy, claims other policy tweaks could achieve a lot. Just as existing policies allow utilities to charge customers extra for installation of renewable energy sources such as wind and solar, future policies could do the same for carbon-sequestration projects. “A carbon price is not the only way to do this,” Friedmann said.
“In a way I am more optimistic for China,” says Jiemin Lu, a geologist at the University of Texas, Austin. “If the top level decides to do something at a larger scale, it will be quickly implemented and resources will be pulled together very swiftly. So to meet this kind of challenge at this scale, it will be more effective in that kind of political system. In the West, it’s always going to be a deadlock.”
Meanwhile, the facts on the ground—and in the air—are quite grim. “So far, we have achieved almost nothing in terms of mitigation of emissions, which are tracking at the upper limit for future emission scenarios. Indeed, in the last decade the world economy has actually recarbonized—shifted back to coal,” says David Victor, professor of international relations and director of the Laboratory on International Law and Regulation at the University of California, San Diego.
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