Dive Brief:

• The controversial Clean Power Plan will certainly face legal challenges and could ultimately wind up in front of the U.S. Supreme Court, but according to analysis by E&E Publishing revisions made in the final regulations appear designed to help the law survive such a fight.
• Between the proposed and final regulations, released this week, the Obama administration pulled energy efficiency as a compliance building block, likely addressing concerns it would overstep the U.S. Environmental Protection Agency's authority.
• Considered to be among the more vulnerable portions of the law, experts said requiring energy efficiency would step beyond the "fence line" of power plants to mandate reductions.

Dive Insight:

The Obama administration's final Clean Power Plan regulations are not even a week old, but experts are already looking ahead to a potential U.S. Supreme Court showdown.

Legal challenges have been filed, rejected and re-filed, and so there is little doubt the process will extend years. But E&E Publishing spoke with a host of legal experts who say the law has been tweaked from its proposed form to help it survive what will likely be a long road of challenges ahead. By removing what was known as "Building Block 4," which focused on energy efficiency, the White House acknowledged that its ability to regulate past the power plant is limited.

In a previous case focused on the EPA and carbon emissions, Justice Antonin Scalia wrote for the majority that the use of best available control technologies cannot be used to force a fundamental redesign of a power faclity, and can only be required for pollutants the source emits.

"Scalia certainly signaled he would find that illegal," Robert Percival, an environmental law professor at the University of Maryland Francis King Carey School of Law, told E&E. "I think this is an example of EPA listening to the comments and recognizing that this is the most legally vulnerable part of the plan. This makes it much more legally defensible."

The final rule calls for deeper cuts, but gives states a longer time to comply. Ths week President Obama announced the EPA would target a 32% drop in greenhouse gas emissions by 2030. The initial compliance deadline was extended two years, to 2022.

Ultimately, it's anyone's guess what the Supreme Court might do should the path of legal challenges lead there.

Former Department of Justice attorney William Jay told E&E that while axing the efficiency measure may have strengthened the law, it's impossible to say for sure what may happen. "If EPA has dealt with that objection, that presumably jumps over one hurdle," he said. "But that doesn't mean the justices in the majority wouldn't see more hurdles in EPA's path."

For more information on the final Clean Power Plan, check out the Utility Dive feature.