Cogen
you are talking about heat recovery. Co-generation facilities have been doing this for several decades. But, the total waste heat gained is not great. Yes, utilities can do so, if there is a need. Some Cities have downtown pipelines for distribution of hot and cold water, with the source being a nearby small generation facility.
There are also a few industrial facilities that can use waste heat at higher temperatures. Those usually have circulating hot oil. This gives temperatures of up to a couple of hundred degrees C. Higher temperatures than that require an on site heat source.
Most of the gains for this type of thing are limited and local. About half of what could be reasonably done is already being done. It takes a good cost/benefit analysis to find if it is worth it for any single facility. You can't be very far from the heat source. Payback is usually required to be less than 7 years. 3 years for some industries.
