Much of the energy we generate, as much as two-thirds, is dissipated as waste heat. But research reported this week in the journal Nature gets us one important step closer to closing that wasteful gap. An international team of scientists have devised a new material capable of converting waste heat into electricity with unprecedented efficiency.

Known as thermoelectric generators, the material generates an electric charge from temperature variations across its two ends. So, for instance, the heat from the hot exhaust gases from your car could be used to generate electricity before escaping from the end of your tailpipe, making your car more efficient. But waste heat is everywhere and scientists envision many potential applications for thermoelectric materials.

As with much of today’s technology, from Tang to heat-absorbing sportswear, thermoelectric generators have a head start in space-based applications. The Mars Curiosity is powered by heat harvested from the radioactive isotope plutonium-238 dioxide. For as long as the isotope produces radioactive heat, Curiosity will have electricity. Of course, that’s fine for a robot explorer on Mars, but what of our more Earthly needs?

The first hurdle for the general application of thermodynamic material is efficiency. Until now, generators have typically retained only 10 percent of the energy from heat. The new design reported in Nature uses an optimized form of lead telluride that effectively doubles the efficiency of the thermoelectric generator, making them easier to mass-produce as well. The problem with lead telluride is its toxicity, making it unsuitable for commercial applications.

Nonetheless, this week’s revelation in thermodynamic generator technology is a big step forward. One day your tailpipe, if you still have one, could be a source of energy.

Of course, entropy and the second law of thermodynamics dictates there will always be some waste heat. There’s no free lunch, but we can certainly make the cost much more efficient.

Main photo credit: Arthur Caranta/Flickr