...they say the country stands to save 3.9 billion gallons of fuel annually,...
They acknowledge there will still be fuel consumption, reducing it 50%, though.
They're also left with the problem of efficiently disposing of the heat from the hotside junction of the Peltier cell.
Why do they think GM rejected this concept? Because the GM engineers are stupid?
Because they hadn't spent long enough in high-school physics class?
Here's the 4-word theory of economics, and it also applies to engineering:
"Ain't no free lunch."