Renewables are greenest when displacing coal, not gas.
With the abandonment of a nationwide energy policy by the previous Congress, states continue leading carbon mitigation efforts. Indeed, existing state policies and renewable portfolio standards (RPS) are already having a significant impact on the U.S. generation portfolio. FERC now proposes to weigh state policy as a consideration in transmission filings. Should state policies guide federal action? Will they suffice to reduce carbon emissions?