"Clean" coal, that still-mythical beast, is rearing its head once again. This time it's in the form of carbon capture and storage (CCS), the technology that promises to remove CO2 from burning coal, liquefy it, and pump it underground. CCS has been in the works for well over a decade, mostly in Europe and Canada, but has recently gained a slew of coal-go-lucky supporters in America. As Yale Environment 360 explains, the cost of retrofitting old plants for CCS is so high that it would only be practical for newly constructed coal plants. By pushing for CCS, King Coal is working to ensure not just its survival, but its expansion well into the future.

Why might this be a terrible idea? Yale 360 counts the ways. CCS is enormously expensive and technically unwieldy, and it could carry risks that would be even more dangerous than releasing CO2 straight into the atmosphere. "CO2, which is buoyant underground, can migrate through cracks in the earth and around old wellheads," the article says. "This is troublesome because CO2 is an asphyxiant--in concentration above 20 percent it can cause a person to lose consciousness in a breath or two." 

Okay, so the very fact that CCS still carries enormous upfront costs and could have unintended side effects isn't persuasive enough to rule it out altogether, as Yale 360 argues. It's an unproven technological discovery that's still in its infancy, and we have to be prepared to invest heavily in cleantech start-ups if we're going to come up with any real solutions. Even so, CCS still looks like a risky wager on all counts. Lots of clean energy projects will be capital- and infrastructure-intensive, but CCS doesn't appear to deliver on the scale that would warrant the huge-scale investment that some are demanding since the U.S. scrapped its biggest CCS program. Take the best-known CCS project, Norway's Sleipner Platform. It's one of the largest off-shore platforms in the world, and it would take at least 10 of those to offset the annual emissions of a single big coal plant, Yale 360 says. And that's not to mention the fact CCS itself is energy-hungry, requiring as much as 20 percent of the electricity a power plant generates.  And while many alt-energy proposals may fail, very few--aside from nuclear--might actually kill people if things go awry.

Even the supporters of CCS have warned that the technology "should be seen as a last resort"--one that shouldn't give us a free pass for us to continue the status quo with the dreamy expectation that we'll just be able to bury our emissions.

--Suzy Khimm