On September 13, the U.S. Court of Appeals for the Seventh Circuit issued a decision affirming the district court in upholding the Illinois zero emission credit (ZEC) program for the state’s nuclear generation facilities.  The Seventh Circuit rejected the appellants’ preemption claims, asserting that “because states retain authority over power generation, a state policy that affects price only by increasing the quantity of power available for sale is not preempted by federal law.”  According to the Seventh Circuit, the exercise of powers reserved to the states does not lead to preemption; rather, they are an inevitable consequence of a system in which power is shared between state and national governments.  In addition, the Seventh Circuit rejected the appellants’ dormant Commerce Clause arguments, ruling that Illinois has not engaged in any discrimination beyond what is required by the rule that a state must regulate within its borders.