At long last, the Koch brothers and their conservative allies in state government have found a new tax they can support. Naturally it’s a tax on something the country needs: solar energy panels.

For the last few months, the Kochs and other big polluters have been spending heavily to fight incentives for renewable energy, which have been adopted by most states. They particularly dislike state laws that allow homeowners with solar panels to sell power they don’t need back to electric utilities. So they’ve been pushing legislatures to impose a surtax on this increasingly popular practice, hoping to make installing solar panels on houses less attractive.

Oklahoma lawmakers recently approved such a surcharge at the behest of the American Legislative Exchange Council, the conservative group that often dictates bills to Republican statehouses and receives financing from the utility industry and fossil-fuel producers, including the Kochs. As The Los Angeles Times reported recently, the Kochs and ALEC have made similar efforts in other states, though they were beaten back by solar advocates in Kansas and the surtax was reduced to $5 a month in Arizona.

But the Big Carbon advocates aren’t giving up. The same group is trying to repeal or freeze Ohio’s requirement that 12.5 percent of the state’s electric power come from renewable sources like solar and wind by 2025. Twenty-nine states have established similar standards that call for 10 percent or more in renewable power. These states can now anticipate well-financed campaigns to eliminate these targets or scale them back.