Old coal's new role

Environmental regulations and competition from gasfired turbines and renewable energy sources are shutting down dozens of older coal-fired power plants across North America and Europe. But some of these aging plants' induction generators will go on spinning for years after their furnaces and turbines are scrapped. That's because operators need new ways to stabilize grids deprived of big power plants, and huge, free-spinning generators synced to a grid's AC frequency-synchronous condensers-are becoming an increasingly popular option.