Out of Sight, Out of Mind: Making Use of Carbon Capture and Sequestration

Carbon dioxide, the versatile gas that puts the fizz in our soft drinks and tonics, is a welcome guest at dinner parties but an orphan of industry—everyone creates it and no one wants to keep it. In “Scaling Up Carbon Dioxide Capture and Storage: From Megatons to Gigatons,” MIT’s Howard J. Herzog explores the central issues involved in transforming carbon capture and storage (CCS) from a boutique technology to a broadly commercial one. He finds that the obstacles are more structural than technical. They include high costs, a patchwork infrastructure of plants and pipelines, lack of a carbon-pricing plan, and insufficient knowledge of the subsurface.

CCS has intuitive appeal. It would allow continued burning of hydrocarbons while depositing the resulting greenhouse gases in saline formations and old oil and gas reservoirs, where it can’t disrupt the atmosphere. More than 85 percent of commercial energy comes from fossil fuels, and Herzog predicts that they will remain the world’s major energy source throughout the twenty-first century. Moreover, CCS is not new. Energy companies have been separating CO2, transporting it, and injecting it into the ground since the 1970s as part of enhanced oil recovery (EOR), a method of recovering inaccessible oil from partially depleted reservoirs.

Yet, the task is immense. Herzog’s paper mines research and defines challenges from beginning to end, but hits on two major concerns: storage and cost. At first glance, storage does not appear to present a problem. The Intergovernmental Panel on Climate Change conservatively estimates that there are 2 trillion metric tons of capacity worldwide, easily enough to accommodate current global output indefinitely. (The United States produces about 450 million metric tons of CO2 each year.) But no one is sure how CO2 might behave and migrate once injected into underground formations, so capacity will depend on which formations prove to be the most cooperative. Large tracts could ultimately be ruled unsuitable or just inaccessible.

The other big roadblock is the lack of carbon pricing. Without it, CCS is just an avoidable cost. A cost, Herzog estimates, that would increase the price of electricity to consumers by 25 to 50 percent even once it’s fully scaled. (The EIA estimates costs for coal-based CCS to be higher than wind, geothermal, and nuclear, but much lower than solar.) A politically acceptable price on carbon phased in by 2015 and gradually escalated would take another twenty to twenty-five years to make CCS cost-neutral by surpassing the estimated long-term cost of capture and storage of about $65 per metric ton of CO2. New technological discoveries could lower costs and help close that gap, but the public pitch for CCS likely will have to move forward without them.

The most striking aspect of CCS is its across-the-board uncertainty, which bubbles to the surface throughout the paper in acknowledged gaps and hedges. Is there enough usable, accessible space underground? Will compressed CO2  remain where we put it? How high could the price on carbon be, if we can price it at all? Would capture plants be built before transport pipelines, or vice versa? Will the public accept unknown risks and the appropriation of subterranean carbon storage rights? We don’t know.

Herzog is convinced that we have to try CCS and must begin now because it is the only technology that will allow us to both use carbon and avoid its worst consequences. “The correct response should be not to get discouraged,” he says, “but to realize that vigorous action is needed to overcome the challenges and that this action needs to be at a significant scale.” One point is certain: if we can find a grand, workable solution for CCS, we ought to bottle it.