A power line system is provided for efficiently using excess electrical energy produced by electric vehicles in a generation mode. A power line detector on the vehicle senses the power line to determine if voltage ripples are present before supplying excess electrical energy from the vehicle to the power line. First voltage ripples are generated on the line by a substation providing power to the power line. Second voltage ripples are also generated on the power line by a ripple generator to allow excess energy from the vehicle to be supplied to the power line in order to charge an energy storage system.