Maybe not banned but they could do a carbon tax like they do with motor vehicles. Or maybe like with appliances where you have an energy rating, with stickers telling you how much electricity it will use per year, possibly with tax incentives to pick the most efficient.

Problem is: how to test that? Even with the most straightforward tests, there are cheaters. Appliances have a special "eco" mode to meet the specs that most people won't use because it barely does the job. And for cars, well, VW have shown us how far companies are ready to go.