The Pennsylvania Commonwealth Court found Wednesday in two rulings that the state cannot enforce a regulation directed by executive order to make power plant owners pay for their planet-warming greenhouse gas emissions because it was created without legislative approval, dealing another setback to the centerpiece of former Governor Tom Wolf’s plan to fight global warming.

The Commonwealth Court found that Pennsylvania’s participation in the Regional Greenhouse Gas Initiative (RGGI), a multi-state initiative with the goal of reducing CO2 emissions from power plants via carbon permits was unconstitutional. The court found that proceeds from the allowance auctions were a tax created by the PA Environmental Quality Board (EQB) and the Department of Environmental Protection (DEP) in violation of the PA Constitution. Pennsylvania’s participation in RGGI was promulgated by the DEP and EQB. The DEP was directed to promulgate rules about joining RGGI due to a 2019 executive order by former Governor Tom Wolf.

A common theme in both cases is Article III Sec. 10 of the PA Constitution, which requires that “all bills for raising revenue shall originate in the House of Representatives.” The Commonwealth court said, “stated simply, to pass constitutional muster, the Commonwealth’s participation in RGGI must be achieved through legislation duly enacted by the Pennsylvania General Assembly.”

RGGI member states distribute CO2 “allowances,” sometimes described as credits. State governments auction allowances to operators of fossil fuel power plants. The allowance takes the form of a license to emit one ton of CO2. Fossil fuel power plants are obligated to purchase allowances from state governments to offset the power plant’s emissions.