The Dicey Future of Carbon Capture
For more than a year engineers near Decatur, Illinois, have been pumping 1,000 metric tons a day of compressed carbon dioxide (CO2) deep into the ground. Skimmed from a nearby ethanol plant, the gas is squeezed into compression chambers and force-fed into pipes that plunge more than a mile and a quarter beneath the surface. The liquefied CO2 is then released into a huge underground layer of crunchy, salt-like rock.
There it will stay, presumably sequestered for millennia, seething through a bed of porous sandstone, sealed off from earth’s atmosphere by thick layers of impermeable shale.
The project, the first of its kind in the United States, will eventually absorb more than 1 million tons of CO2 each year, disposing of a relatively small quantity of the pernicious greenhouse gas that most scientists agree is driving global warming.
Yet, for all the talk and hope about what experts refer to as “carbon capture and storage,” or, sometimes, “carbon capture and sequestration,” as a way to burn cleaner coal and cleanse a broad range of industrial processes, the technology today faces so many economic, political and scientific obstacles that it is unlikely, over the next couple of decades, to have much impact on the serious environmental problem it is meant to address.
There have been numerous small-scale demonstration projects using carbon capture and storage (CCS), but few scaled industrial operations. Experts estimate that currently 25 million tons of carbon dioxide are being stored annually around the world in carbon capture projects. That’s less than 0.1% of the more than 33 billion tons of CO2 that flows into the atmosphere every year as a result of human industry, transportation and agriculture. Environmentalists say that, in order for CCS to reduce global carbon emissions to an acceptable level, the technology will have to dispose of 3.5 billion metric tons of CO2 a year.
The question is: Can this process be improved upon, and made sufficiently cost effective and politically acceptable, so that it absorbs a significant amount of the gas that man pours into the environment?
Government Agencies Still Back Capture
The U.S. Department of Energy (DOE) says the answer, unequivocally, is yes. “It’s certainly an incredibly important part of what’s necessary to achieve the global targets [of carbon reduction],” says Charles McConnell, assistant secretary for fossil energy at the DOE.
In Canada, there remains a similar commitment to CCS. “Canada is a world leader in carbon capture and storage, and we are in an excellent position to use the technology on a wide scale,” says Minister of Natural Resources Joe Oliver.
But, for all the optimistic talk and considerable public spending, there has been little progress in terms of implementing CCS in North America.
The U.S. Congress has authorized $6.9 billion for carbon capture in the past seven years, according to the Congressional Budget Office. Expenditures of about $2.2 billion have so far produced little more than a host of small projects. The Decatur project is still in demonstration stages, while another major project in Illinois, FutureGen, planned as a zero-emissions, coal-fired power plant with $1 billion in federal stimulus funds, has faced a host of problems, including the recent abandonment of the project by four power companies that had been investors.
In Canada, the government of Prime Minister Stephen Harper has allotted $800 million to a Clean Energy Fund, much of which is going to CCS projects. The biggest project so far? Shell Oil’s Quest Project, which will eventually take 1 million tons of CO2 a year from a heavy oil processing plant in Alberta and inject it into a site 6,500 feet beneath the surface. The project, which, as planned, will start sequestering CO2 in 2015, is receiving $120 million in federal funds. The provincial government, which has its own CCS fund, is contributing $745 million.
Questions on Storage, Expense and Scale
Even while implementation efforts nibble at the corners of the emissions problem, geologists are raising new questions about the long-term viability of storing such huge quantities of CO2 beneath the ground.
Widespread fracking—pumping water into deep chambers to retrieve hard-to-reach pockets of crude oil—has shown in recent years how changes in subterranean pressure can touch off small earthquakes. In 2011, fracking procedures prompted a series of small earthquakes near Guy, Arkansas, registering up to a 4.7 magnitude. There were similar tremors that year near the border of Colorado and New Mexico, with earthquakes reaching a 5.3 magnitude. Some geologists have warned that similar seismic events could jeopardize the security of sites where caches of CO2 are being stored, perhaps even releasing the captured gas into the atmosphere.
Other critics, including representatives of the steel industry, are raising questions about the expense of CCS. The U.S. Environmental Protection Administration is requiring industries like steel and aluminum to show that, in new plants, they employ the “best available control technology.” For large-scale new steel plants, CCS is one measure that steelmakers should employ to mitigate the carbon emissions, EPA says. The American Iron and Steel Institute condemns the agency’s position, which has still not been implemented, as speculative and needlessly expensive.
But, even when it works, CCS seems to show minor promise.
The year-old Decatur, Illinois, project extracts CO2 from furnaces that power an Archer Daniels Midland (ADM) ethanol refinery. The CO2 is captured using oxygen instead of air to burn the coal that fuels the refinery’s fermentation process, rendering a pure form of CO2, which is then transferred to an adjoining compression facility.
The liquefied CO2 is pumped into the ground, where it will be monitored with seismic receivers and pressure and temperature monitors. When the project is fully deployed, it will process about 3,000 metric tons a day, compared with the 1,000 it processes now, says project director Scott McDonald.
“For a sense of scale, bear in mind that some large power plants can emit about 14,000 to 15,000 tons of CO2 per day,” he says. Indeed, the ADM ethanol plant sends about 4.5 million tons of CO2 a year into the atmosphere, dwarfing the 1 million tons that the fully implemented CCS plant is supposed to sequester beneath the ground.
Advocates hope the ADM work will have wider ramifications. The layer of saline rock, the so-called Mount Simon Sandstone, has vast capacity, which geologists estimate could hold up to 151 billion metric tons of captured CO2. If the ADM project proves the viability of socking all of that captured gas below ground, a gateway for other nearby projects could be opened. The sandstone layer covers two-thirds of Illinois, as well as parts of Indiana and Kentucky and underlies what the Massachusetts Institute of Technology calls “one of the largest concentrations of coal-fired power plants in the world.”
Equal to a New Oil Industry?
The ADM project is being paid for with $141.4 million in funds from the DOE and $66.5 million from the private sector, which raises troubling questions about funding. Who will ultimately pick up the check for new CCS projects? Sequestering 3.5 billion tons of CO2 a year would be the operational equivalent of oil industry production every year, two Stanford geologists note in a recent paper on CCS.
How do you “capture” carbon? There are three techniques:
1. Oxy-fuel combustion: Most often used in coal-fueled power plants. Coal burns in pure oxygen instead of air, coming out the other end as steam and CO2.
2. Post-combustion carbon capture: CO2 is removed from exhaust gas through absorption by solvents.
3. Pre combustion carbon capture: Coal or natural gas is pre-treated, converted to CO2 and hydrogen and separated. The CO2 is sent to a compression facility and the hydrogen is burned to produce electricity or fuel.
“It would be like creating an oil industry in reverse,” says Mark D. Zoback, who, along with co-author Steven M. Gorelick, notes that the CO2 storage goal is roughly equivalent to the 27 billion barrels of oil the world produces each year.
Obviously, since the stressed-out U.S. federal budget can’t pay for an entire CCS industry, it’s up to private enterprise to carry the ball, experts say.
In some countries, this process is already under way. Currently, 75 large-scale CCS projects are under way across the globe (storing at least 400,000 metric tons of CO2 a year from coal-fired power plants and other carbon producers). The number is increasing, says the Australia-based Global CCS Institute—though by only one since last year, given the cancellation of eight existing projects. In its annual report, the institute mentions ambitious new projects in Norway, Spain and Australia, as well as Canada’s Quest project, most of which use a blend of private and public money.
Of the 74 projects, however, only eight are actually in operation, with eight more under construction. The rest are in various stages of planning. North America has six up-and-running, small-scale CCS projects (including Decatur, Illinois).
No Incentive for the Private Sector
In the United States, private companies see little incentive for involvement. The absence of a carbon tax doesn’t spur big industries into action, and the costs of investing in CCS technology are prohibitively high, according to some industry trade groups. Experts estimate that adding a CCS component to a new coal-fired power plant would add 75% to the cost.
Politically, the issue of climate change appears to be anathema to most American elected officials under current economic conditions. Passing a carbon gas tax, such as the cap-and-trade bill that was defeated by congressional Republicans in 2010, seems unlikely even though President Obama did mention climate change in his election night acceptance speech.
Under the circumstances, the DOE has shifted its focus from what McConnell calls “a waste disposal model” to one centered on finding “commercially viable” uses for the CO2 in the atmosphere. The answer, McConnell says, is “enhanced oil recovery” (EOR), injecting captured CO2 into depleted oil wells to pull out hard-to-reach pockets of crude. The gas flushes out the oil and stays sequestered in the empty spots.
The DOE says EOR could add as much as 60 billion barrels of crude oil to the nation’s recoverable reserves. A joint United
States-Canada EOR project in Saskatchewan uses 1 ton of CO2 to squeeze out two or three barrels of oil from depleted oilfields, says Canada’s Petroleum Technology Research Centre. The cost of capturing and compressing CO2 is currently about $60 per metric ton, the DOE says. According to McConnell, the technology is competitive with standard oil drilling methods.
In fact, American oil companies have used EOR since 1972. Five of the eight large-scale integrated projects that the Global CCS Institute lists as up-and-running are EOR projects, and five of the eight that are under construction are EOR projects as well.
Another Big Question
That leaves the problem of possible geologic catastrophe from both CCS and EOR. Can injection of huge amounts of compressed gas touch off earthquakes that would breach the cap rock holding the gas underground?
A report issued in June by the National Research Council (NRC), the research arm of the National Academies of the United States (including the National Academy of Sciences and the Institute of Medicine), raises questions about long-term storage, noting that even short-term fracking operations have induced seismic events.
“Increasing pressure over significant areas underground prompts gas to spread out over an even bigger area,” says Murray Hitzman, a professor of economic geology at the Colorado School of Mines and the head of the NRC investigation. “The general impression is that, the bigger the area, the more the chance of touching intersecting faults.” Additionally, concern remains around whether the sequestration of CO2 for extended periods could lead to the dissolution of certain kinds of rock, Hitzman says. The acidic eating-away process could eventually provide pathways for the CO2 to escape, he says.
Escaping CO2 can present massive threats. For example, catastrophic events such as Japan’s earthquake in 2011 could conceivably touch off huge, lethal releases of CO2.
Gorelick and Zoback, the Stanford geologists, argue in their paper that even micro quakes not felt at the surface could damage the cap rock at CCS storage sites. “Small earthquakes have occurred even when trivial amounts of gas were injected,” Zoback told Forward. “We need to take the earthquake problem very seriously. I think time will tell, but our assumption is that the possibility of earthquakes will rule out a lot of places considered [as storage sites] in the past.”
Still, the world continues to cook. Scientists estimate that the global average temperature increased by 0.74 degrees Celsius in the 20th century, and the pace is currently increasing. According to recent estimates, temperatures could increase an additional 6 degrees by 2100 without massive mitigation efforts.
Climate change experts have set a global goal of keeping the average temperature increase to less than 2 degrees in this century. “It’s the guardrail beyond which we can no longer maintain civilization as we know it,” says Durwood Zaelke, president of the Institute for Governance and Sustainable Development, a network of environmental professionals from around the world promoting sustainable energy policies.
The 2-degree goal, he says, can only be achieved with an array of technologies, including wind, solar, geothermal and nuclear energy and increased efficiencies in the use of fossil fuels. There are other techniques for capturing CO2, Zaelke says, such as creating or beefing up forests and wetlands and letting photosynthesis do the job. But carbon capture, he insists, is essential to the process.
Edmund Newton is a Washington, D.C.-based writer, formerly of the L.A. Times, Newsday and the New York Post, as well as the former managing editor of New Times-Broward Palm Beach. He has written for, among others, The New York Times, Time, People, Daily News Sunday Magazine, Black Enterprise, the Ladies Home Journal, Essence and Audubon.