Whether in a car, power station or some other industrial process, a few percent of waste heat recovered could make a significant difference to the efficiency of the system overall – dependent on cost and complexity – clearly TE devices have the potential to provide this in some applications.
Another perspective to take with regard to Fo-Fu is robustness and reliability. Any improvements in energy recovery may give the option to run at a lower frequency. Less pulses per second should result in improved reliability and a longer maintenance schedule – think third world – sorry, I mean “developing countries” or is that “emerging markets”. There’s also marine and eventually space applications where design priorities will likely differ.

I originally considered the subject of heat recovery due to “net energy paranoia”, hopefully the numbers will be quite sufficient. but its always nice to have options.