Your blog is interesting and correct in that thermoelectric and thermionic converters are used to generate electricity from a given heat source (providing that there is a useful temperature gradient) including waste heat from a radioactive source. However, it is unlikely, at the present time, that radioactive heat sources will enjoy widespread terrestrial use, partially because they are very very expensive, and partially because of health and security concerns. The generation of electricity using thermoelectrics and thermionics is a very active academic field with thermocouples being placed at about the bottom of the barrel in terms of efficiency. So the BMW device looks to be purely cosmetic rather than breakthrough ‘green’ science.

with kind regards,

Andy

“deep space probes often do use radioactive materials to generate electricity, being that they are too far away from the sun to use solar panels. They just use the heat generated by the decaying radioactive materials to drive a thermoelectric generator… the same sort of generator that BMW plans to use. But BMW will just use waste heat from the exhaust instead of heat from decaying radioactive material.”

The truth is somewhere in the middle.. :)

There is no nuclear holocaust..

http://www.autoevolution.com/news/radioactive-bimmers-from-hell-4775.html

The normal device for this purpose would be a peltier junction, which isn’t radioactive. There was a theoretical device proposed a few years ago that could directly generate electricity from heat (as opposed to a heat differential), but nobody had any idea how to create one to test.