Neal Boortz has a good explanation of the new Bush EPA regulations.

When Clinton arrived in Washington he decided to throw a bone to the eco-radicals. He changed the terms of the New Source Review process to make it virtually impossible for any existing power plant to increase generating capacity unless the entire plant was brought up to the most stringent current clean-air requirements. Since this would be economically disastrous, it spelled an end to even small increases in generating capacity.

Here’s an example of how the rule worked under Clinton with one particular plant. This plant used coal to generate steam which turned the turbines on a generator and produced electricity. Someone developed a new propeller for this steam turbine. By removing the old propeller and installing the new one this plant could increase its generating capacity by 15%. That’s 15% more electricity from the same plant without one additional ounce of pollution. Now that sounds like a rather good deal, doesn’t it? The Clinton EPA, however, said “no.” The plant couldn’t install the new propeller unless the entire plant was brought up to current clean-air standards. So, the old propeller remained and the extra electricity was lost.

Under the new proposed rules from the Bush EPA, the plant would have been allowed to install the new propeller.