It's been a slow process to select the innovations we'll use to beat a path to a bright green future (both because the issues are extremely complex and there are enormous fortunes at stake, and because the delay itself serves the interest of some extremely powerful interests), but we do seems to be on the way to sorting out some of the less realistic "middle road" technologies.
Eoin O'Carroll, over on the Christian Science Monitor's Bright Green Blog, lays out the basics on clean coal in a nicely written post:
we arrive at the latest definition of clean coal – “zero greenhouse-gas emission coal.”Industry groups say they can achieve this by capturing the carbon dioxide produced by the burning coal and pumping it underground. This so-called carbon-capture-and-storage, or CCS, technology has been succesfully tested on a small scale, but it has yet to be proven economically viable. Citing rising costs, in February the Department of Energy pulled the plug on an ambitious CCS project, the $1.8 billion FutureGen power plant in Matoon, Ill.
One leading management consulting firm, McKinsey & Company, said in a recent report [PDF] that CCS technology will not be economical until 2030. That will most likely be too late to help avert catastrophic climate change.
Critics of CCS point out that the energy required to capture and sequester emissions will erase many of the efficiency gains made in recent decades.
Meanwhile, the AP has a good piece on why cellulosic biofuels are farther off then you've been hearing:
It may be one of the biggest green gambles of the century: a national goal of converting wood, grass, corn stalks and garbage into 16 billion gallons of cellulosic biofuels annually by 2022.No commercial-scale refineries exist, researchers have yet to agree on the best technology for fuel conversion and there is no distribution network to handle fuel once it is made.
Add it all up and the country's not even close to meeting the EPA's renewable fuel standards a mere 14 years from now.
Meanwhile, yet another report concludes that hydrogen fuel-cell-powered cars are probably a non-starter (and that the fixes to the problems of the car are not under the hood, as cutting average automotive emissions in half by 2035, using technological innovation alone, would be extremely difficult).
Now, the usual caveats apply -- namely, that we should keep an open mind to the possibility of breakthroughs in any area of technological development, and we may well end up using some aspects of a whole array of new approaches -- but it does seem to me more and more that we might almost postulate a principle of sustainable design, that technologies designed to "swap out" a newly-modified version of an energy or transportation system for its dirtier antecedent are almost invariably not good enough. We need to redesign the systems themselves, not just the technologies that make up those systems.
