A lot of colleges use cogeneration plants. Almost nobody else does. From what I understand, it nearly doubles the total efficiency of burning coal, though the o

A lot of colleges use cogeneration plants. Almost nobody else does. From what I understand, it nearly doubles the total efficiency of burning coal, though the output is not more electricity but heat. The physics is pretty simple as explained by the Carnot cycle [1]: Efficiency <= 1 - Tc / Th, where Tc is the cold exhaust temperature and Th is the hot temperature. This is of course a theoretical ideal engine. The issue is that for something like a coal or oil or gas plant, Tc is still damn hot. Something like 900 degrees F is common. It's too low to use for a second cycle of electricity usage, but it's still plenty hot to heat your living room. [1] https://en.wikipedia.org/wiki/Thermal_efficiency#Carnot_efficiency https://en.wikipedia.org/wiki/Thermal_efficiency#Carnot_effi...