In its ongoing testing of plug-in hybrid electric vehicles, San Diego Gas & Electric (SDG&E) has found that plug-in hybrids offer significant improvements in mileage and reductions in emissions when compared with standard hybrid and gasoline vehicles.

SDG&E tested the performance of two 2007 model standard hybrid vehicles and then converted them into plug-in hybrids using a lithium-ion battery conversion kit (subsequently replacing the prototype battery with a production model battery).

Compared with the standard hybrid, the plug-in hybrid achieved 68 miles per gallon, corresponding to a 58 percent increase in gas mileage and a 37 percent decrease in CO2 tailpipe emissions, and a 10 percent reduction in fuel costs. Compared with a conventional gasoline fueled vehicle that averages 22 mpg, the plug-in hybrid achieved a 68 percent reduction in tailpipe emissions and 54 percent reduction in overall fuel costs.

California’s electricity system has the capacity to recharge as many as 4 million plug-in hybrids when charged during off-peak hours when electricity use is low. The plug-in hybrid’s fuel cost savings over traditional gasoline-powered vehicles would save these 4 million consumers approximately $4.2 billion a year at today’s average gasoline price of $3 per gallon when compared to 15 cents/kWh of electricity for 14,400 miles driven annually.

With SDG&E’s deployment of smart meter technology, the interface with these vehicles in the future will allow customers to schedule charging time and select the lowest rate for charging.

SDG&E said the study results confirm the viability of electricity as a clean and low cost transportation fuel and validate the increased efficiencies of plug-in hybrid technology.

“California has the most aggressive greenhouse gas reduction goals in the nation, with nearly 40 percent of those emissions coming from transportation,” said Hal D. Snyder, vice president of customer solutions for SDG&E. “Integrating clean transportation alternatives, like plug-in hybrid and all electric vehicles, will be critical to achieving the state’s goals. SDG&E will do its part to help ensure the San Diego region is ‘plug-in’ ready when electric vehicles hit the road.”

Plug-in hybrids and all-electric vehicles are expected to become widely available across the nation in late 2010.

The converted plug-in hybrids recharge their batteries through a standard 110 V household outlet and charge in five to six hours for a 5 kWh lithium-ion battery. In the future, plug-in electric vehicles will primarily charge off 220 V supply for faster charging time on larger batteries. Gas mileage by the plug-in hybrids is greatly improved because the vehicles use electricity from the grid and can run in electric mode longer and more often than standard hybrid cars.
 
SDG&E is part of a 48 utility coalition with the Electric Power Research Institute and General Motors, which is working to accelerate the large-scale deployment of plug-in hybrid electric vehicles and to create a blueprint for an electric fuel infrastructure.

SDG&E has also entered into a partnership with Nissan to help develop the market for zero emission electric vehicles and charging infrastructure in the San Diego region.  Under the partnership, SDG&E is serving as the local San Diego coordinator to help assemble a critical mass of regional electric vehicle fleets that municipalities, universities, the military, the port, private fleets and others use daily.
 
SDG&E also is collaborating with the San Diego Association of Governments (SANDAG) and other local organizations to assess electric vehicle viability and charging infrastructure needs, as well as customer needs and education.

SDG&E, which provides energy service to 3.4 million consumers through 1.4 million electric meters and more than 840,000 natural gas meters in San Diego and southern Orange counties, is the host utility for Smart Energy West Coast 2009.