A pair of southeastern U.S. electric utilities will soon start testing a fleet of converted plug-in Toyota Priuses to evaluate a smart charging system. Duke Energy Carolinas and Progress Energy will be evaluating both cross utility charging and billing and vehicle-to-grid technology. The project will look at the issues of tracking energy usage and billing when a car that is subscribed to one company charges on another's network. Similarly, energy fed back to the grid from the cars will need to be tracked so that drivers get appropriate credit. V2Green will provide the communications modules that will identify the car when plugged into the grid for billing purposes.