The problem that supporters of the proposed 600-megawatt plant never recognized was this: Planet Earth is not a perfect place to build a coal plant. Coal is too dirty; it has become too expensive to mine, ship, and burn; and it is the number-one source of climate-changing carbon emissions. If the world hopes to escape the worst effects of airborne toxins and global warming, it must stop burning the stuff-the quicker the better. So Wolverine’s cancellation of its so-called “Clean Energy Venture” puts the firm in step with the rest of the country and the world.