In addition to reducing energy cost, V2G technology will allow consumers to be able to sell back energy to the utility during the hot summer months when energy demand is the highest. Hybrid vehicle owners may sell energy at the price threshold they select. When the price reaches this point, the utility will automatically take energy from the vehicle. The owner will have enough energy left over for the drive home. Payment to the vehicle’s owner can be made in the form of earned credits from the amount of energy used by the utility toward their monthly energy bill.
V2G technology can increase the availability of renewable energy used during peak energy hours. Plug-in electric hybrid vehicles (PHEVs) may charge their batteries at night when energy is inexpensive and is generated with a larger percentage of renewable resources. While electrical utilities usually have to buy power from expensive, less efficient, fossil fuel power generating sources during the day or times of maximum demand. But with PHEVs, utilities may purchase the renewable energy stored in the vehicle batteries.
PG&E demonstrated the first-ever utility Vehicle-to-Grid (V2G) technology at Silicon Valley Leadership Group Alternative Energy Solutions Summit in California. The PHEV, a converted Toyota Prius, featured a 180 pound lithium battery that takes up the bottom of a back trunk where a tire would go. The vehicle produces about 9 kilowatts of electricity while the average house uses about 2.5 kilowatts of electricity on hour.
The PHEVs charge by plugging into a three-prong 110- to 120-volt outlet. Flipping a switch sends the charge to the home from the car, if the home needs energy during a blackout or high energy consumption days.
For the demonstration, the Prius ran several lights and appliances after reversing the flow of energy from the outlet to the vehicle.
The plug-ins, like the traditional hybrid, have both electric motors and batteries as well as a gasoline engine which turns on when the car runs about 20 to 25 miles per hour.