So the EU is considering regulations on lamps’ power usage.1 If they don’t exempt entertainment lighting2, this is going to be a disaster. All existing equipment (from tungsten to LED to arc) will become obsolete. Touring shows to or from the EU will require major reworking. And there are significant hurdles for manufacturers to even create lights that will both illuminate the stage and satisfy the regulations. So much for the West End.
Oh, and stage lighting uses less energy that keeping the water hot.