SAN DIEGO — The white Toyota Scion xB parked in a corner of the vast convention center here doesn’t look too unusual, until you notice the fat cable plugged into its bright orange front grille.
But its owners say it might be the smallest unit of California’s electrical grid. The car, a plug-in hybrid electric vehicle , has been retrofitted by AC Propulsion to respond to signals from the California Independent System Operator — giving it the ability to send power from its battery back to the grid.