Yesterday, EPA issued a guidance document intended "to assist permit writers and permit applicants in addressing the prevention of significant deterioration (PSD) and title V permitting requirements for greenhouse gases (GHGs) that begin to apply on January 2, 2011." The most significant aspect of the new guidance is that, in many cases, implementing energy efficiency measures will be the best available control technology (BACT) for GHGs. Some industry proponents had been worried that GHG permitting would require fossil fuel-fired power plants to implement unproven carbon capture and storage technologies. EPA hopes that the permitting guidance will allay this concern and "rejected suggestions from Republicans opposed to the new [GHG permitting] rules that they would impose onerous and costly conditions on energy firms that will damage the economy and lead to a de facto ban on new facilities."

Beginning January 1, 2011, new sources and major modifications that are already subject to prevention of significant deterioration (PSD) and Title V permitting will be required to consider GHG emissions in obtaining or renewing their permits. Beginning July 1, 2011, new sources that have the potential to emit at least 100,000 tons per year of CO2 equivalent and major modifications that could increase GHG emissions by that amount will become subject to the PSD and Title V permitting programs on the basis of GHGs alone. EPA estimates that these first two steps of its Tailoring Rule will capture facilities responsible for almost 70% of national GHG emissions. The most important component of these permitting programs, is the PSD program's requirement that facilities implement BACT for permitted pollutants.

You can read more at EPA's GHG permitting page, or comment on the new guidance here.