People concerned about global warming talk about how to force generators of heat-trapping gases to shoulder the expense of cutting their emissions. But some cuts come easy, at no cost beyond spending that was planned anyway for other purposes.
New York University, for example, is in the final phases of opening a new power plant that provides electricity for its lights, elevators and computers and steam for heating and cooling water. The new plant is nearly 90 percent efficient, meaning it gets almost three times as much useful energy out of a unit of fuel as a typical utility power plant does. And its carbon dioxide output is 23 percent smaller than that of N.Y.U.'s old system.