Update

The notice of proposed rulemaking (NPR) for carbon emissions from new power plants is now available, here, and the EPA press release explaining it here. As that press release explains:

Under today’s proposal, new large natural gas-fired turbines would need to meet a limit of 1,000 pounds of CO2 per megawatt-hour, while new small natural gas-fired turbines would need to meet a limit of 1,100 pounds of CO2 per megawatt-hour. New coal-fired units would need to meet a limit of 1,100 pounds of CO2 per megawatt-hour, and would have the option to meet a somewhat tighter limit if they choose to average emissions over multiple years, giving those units additional operational flexibility.

As explained below, the public comment period for these rules will be open for 60 days. This is not the first proposal, of course, but the second: Proposed rules were issued in April 2012, followed by an enormous onslaught of comments; those are being formally rescinded today.