At the core of the concept is a layer of piezoelectric material underneath the rubber of the tire. Piezoelectric materials can generate electricity from the application of mechanical force, but in this instance, the (non-specified) 'thermo-piezoelectric' material takes excess heat from the outside of the tire and converts it into electricity.
The heat comes from the friction of the tire on the road, the sunlight acting on the tire, or even just the vibration and bumps of driving along the road. It's unclear how much electricity these magic tires would be able to regenerate, or how much the techno-magic tires would end up costing. But at least it's refreshing to know that the tire companies are still thinking way, way outside their rubber-lined boxes. [Goodyear]