The EPA filed its brief defending the Clean Power Plan rule earlier this week, and I believe most of the amicus briefs are in as well. The case is currently before the D.C. Circuit Court of Appeals. Implementation of the CPP was stayed by the U.S. Supreme Court, but states like Minnesota continue to make progress on their plans to meet the targets set in the federal rule.
Our friends at the Environmental Defense Fund have all the briefs posted on their website, including the one in support of EPA that Minnesota joined. Oral argument in the case is scheduled for June 2.