The International Energy Agency calls (pdf) CCS “essential to the achievement of deep emission cuts estimates,” and estimates that at least twenty “full-scale” CCS projects need to be underway by 2010 for the technology to take flight. Some think it’s a flight of fancy.

A recent article in The Economist wisely pointed out that, “CCS features prominently in all the main blueprints for reducing greenhouse-gas emissions” at a reasonable cost. But “the world’s leaders are counting on a fix for climate change that is at best uncertain and at worst unworkable,” the magazine went on to argue. “In a purely technical sense, CCS looks promising … The problem with CCS is the cost.”

Utilities, the magazine reasoned, are simply not ready to invest in such an expensive technology. But a lot changed in the weeks after its article appeared. Just five days later, The New York Times and The Washington Post covered Congressional and General Accountability Office reports which had found, respectively, that the cancelling FutureGen had set back CCS development by a decade, and that the Department of Energy’s decision to do so was based on a grossly overestimated the cost projection.

Then came the New York Times article with the headline about stimulus money putting CCS projects on a “faster track.” In it, reporter Matthew Wald described a number of projects scattered throughout the U.S. where utilities such as Duke Energy and American Electric Power are investing in CCS. The investments and the scale of the projects themselves are still much smaller than what the International Energy Agency would like to see, however.

There are also mixed feelings among the venture capital community. In the The Wall Street Journal’s annual “Eco:nomics” special report (an excellent read all around), one Silicon Valley executive told reporter Alan Murray that his firm is backing CCS as one option among many. But the vaunted clean-energy investor Vinod Khosla demurred, saying that, “Today, presuming I didn’t care one bit about the environment, investments that are carbon-heavy are poor economic-risk-adjusted bets.” Even optimistic experts seem to agree that it will take at least fifteen years for CCS to mature.

Indeed, there is not a single large power plant using CCS today—just a handful of small demonstration plants using a variety of capture and/or storage techniques. In early April, Scientific American’s Biello penned a useful five-part series that explained the various capture, transportation, and storage options for carbon dioxide, as well as the various existing projects and those that are on the way. One of the report’s more interesting revelations is that, so far, carbon dioxide injected underground has stayed put. Leakage is a major concern among detractors, but the packages includes an intriguing slideshow with a graphic of carbon dioxide’s stable accumulation in Norway’s thirteen-year-old Sleipner gas field, the world’s oldest CCS project.

Biello came to the same conclusion as The Economist, reporting that “the primary problem” with carbon capture and storage projects is cost. Of course, cost is intimately tied to the technology itself; while most of the elements for CCS already exist, they undoubtedly need to be refined and expanded to operate at a much larger scale in order to be effective (if that is even possible).

M.I.T. engineer Howard Herzog told Biello that most of the cost comes in the capture stage (which can involve pre- or post-combustion processes, or something called oxyfuel combustion). But there is some disagreement about that. For instance, the vice president for R&D at Vattenfall, one of the leading investors in CCS, recently told the International Herald Tribune that, “If the timetable for 2015 is not held, it is probably not due to the capture plant but problems with permission for storage and pipeline transport.” Others think that permission isn’t even the issue, but rather the sheer scale of infrastructure required. Last year, for example, the New York Times’s Andrew Revkin cited calculations by Vaclav Smil at the University of Manitoba, who “estimated that capturing and burying just ten percent of the carbon dioxide emitted over a year from coal-fire plants at current rates would require moving volumes of compressed carbon dioxide greater than the total annual flow of oil worldwide.”

Of course, none of these concerns have stopped governments and companies around the world from moving forward with CCS. In the last month, the press has covered a controversial CCS bill in Montana, which died in the state legislature because of confusion about the ownership of underground storage space; agriculture giant Archer Daniel Midland’s quest to bury carbon dioxide in Illinois; a New York startup’s novel proposal to store the gas underneath the ocean floor; and new CCS projects underway in France and China.

Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard.