Comment threads on this blog have previously been rife with discussion about boosting the efficiency of industrial processes through the use of waste heat. It does seem intuitively undesirable to have something like a nuclear power plant venting a significant portion of the total energy being expended from fission in the form of hot air or water being dumped out into the natural environment.
A machine installed at Southern Methodist University demonstrates that there are situations where waste heat can produce a decent amount of electricity (50 kilowatts) at an acceptable cost, and with a payback period of just three or four years. The machine uses an Organic Rankine Cycle, in which a high molecular mass organic fluid is used to convey the waste heat. This is necessary to produce useful work, and eventually electricity, from relatively low temperature sources. As energy prices continue to rise, you can expect to see more such equipment being developed and deployed.