Busted by the First Law of Thermodynamics

In reading Mr. Singer’s letter [Letters, April], I couldn’t help but notice the absence of any mention on his part of the fossil fuel emissions/greenhouse gases that would be produced by the increased demand for electricity from the existing infrastructure—as to whether or not the air quality of the city would be improved by mass-transit’s conversion to electricity. This seems to me to be contingent on where the power plants are located and what fuel is being used. But something tells me that Newton’s First Law of Thermodynamics might be of use in this discussion.
Robert Carter, Eagan