A collection of electric utilities, state commissions, and trade groups filed briefs with the U.S. Court of Appeals for the District of Columbia Circuit May 28 challenging Order 1000, a transmission planning rule the Federal Energy Regulatory Commission is currently implementing. The groups argue that the rule, meant to remove barriers toward building more renewable-friendly long-distance power transmission infrastructure, will lead to high costs for consumers and erode authority of state and regional regulators. FERC’s response is due September 25.