RICHLAND, WASH. --- An upcoming report from the Pacific Northwestern National Laboratory, operated by the Energy Department, is expected to refute reports that widespread plug-in hybrid use would pose a threat to the electrical grid. In fact, the report asserts that plug-in hybrids could actually help stabilize the grid if owners charged their cars during times of low demand -- and if the vehicles could return extra energy to the grid when needed while they're parked during peak demand. Because utilities have enough power plants to supply electricity when consumers operate their air conditioners at full blast, they also have excess generating capacity during off-peak hours. There's enough extra generating capacity during the night and morning to permit more than 80 percent of today's vehicles to make the average daily commute solely using this electricity. MIT's Technology Review published a preliminary summary of the report's findings.