When it comes to energy, heat is a big waste. Sometimes we can put waste heat to good use, like by redirecting steam from power plants to heat homes. But a lot of other times, heat is just lost. Take, for instance, when your car tires run against the asphalt of the road. Usually, the friction between your tires and the road turns some of the car's energy into heat, which just dissipates into the surrounding air or ground, lost forever.

Engineers at Goodyear recently showcased an energy harvesting solution, a concept tire called the BH-O3. The BH-O3 is a tire with an inner coating that generates energy from the tire, which is then fed back into the car's electrical system. The material, which the promotional video doesn't describe, can generate electricity in two ways, either from the tire being squished against the road as it moves or from the tire heating up.