Sorry, Tesla, but someone just stole the thunder from the electric big rig you were planning to unveil this fall. The engine giant Cummins has unveiled a concept semi truck, the AEOS, that runs entirely on the power of an electric motor and a 140kWh battery pack. It's roughly as powerful as a 12-liter fossil fuel engine and could haul 44,000 pounds of cargo, just without the emissions or rampant fuel costs of a conventional truck. There's speedy 1-hour charging, and Cummins is even looking at solar panels on the trailer to extend range. It's a promising offering, although Elon Musk and crew might not lose too much sleep knowing the limitations.