Plug-In hybrid electric vehicles excel on MPG and emissions reductions, SDG&E study confirms

Media Contact:
Denise King

San Diego Gas & Electric

(877) 866-2066


        SAN DIEGO, Sept 24, 2008 – A year-long study by San Diego Gas & Electric (SDG&E) has confirmed the viability of electricity as a clean and low-cost transportation fuel and the advantages that plug-in hybrid electric vehicles offer over standard hybrid electric vehicles for increased gas mileage and lower tailpipe emissions.
        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.  When compared with the standard hybrid, the plug-in hybrid achieved a 60-percent increase in gas mileage, a 37-percent decrease in carbon dioxide (CO2) tailpipe emissions, and an 18-percent reduction in fuel costs.  When compared with conventional gasoline-fueled vehicles that average 22 miles per gallon (MPG), the fuel cost savings jump to 57 percent.

        Today, California’s electricity capacity could 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 nearly $6 billion a year at today’s average gasoline prices.

        “The potential for plug-in hybrids to reduce our dependence on foreign oil, reduce greenhouse-gas emissions and reduce consumer expense for transportation fuel is significant,” said Hal Snyder, vice president of customer programs for SDG&E. 

        In response to increased interest in alternative-fueled vehicles, SDG&E evaluated the two standard hybrid vehicles for six months and, using the same pool of drivers, evaluated the converted plug-in hybrid vehicles for an additional six months.

        Original equipment manufacturer plug-in hybrids are expected to be delivered to showroom floors across the nation in late 2010 and the efficiencies are expected to be higher than those demonstrated in SDG&E’s study.

        The converted plug-in hybrids recharge their batteries through a standard 110-volt household outlet and charge in five to six hours for a 5-kilowatt-hour lithium-ion battery.  Original equipment manufacturer plug-in hybrids will recharge in as little as three hours using a 240-volt wall unit for an 8-kilowatt-hour battery.  Gas mileage in 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. 

        Among the study’s results are:

        • The plug-in hybrid achieved 67 MPG, a 60-percent increase over the standard hybrid’s 42 MPG and a 205-percent increase in MPG compared with a standard car at 22 MPG;
        • The plug-in hybrid achieved a 37-percent reduction in CO2 tailpipe emissions when compared with a standard hybrid and a 67-percent reduction compared with a gasoline-powered car; and
        • The plug-in hybrid had a monthly fuel cost of $94, an 18-percent reduction from the fuel costs of a standard hybrid ($115) and a 57-percent reduction when compared with a gasoline-powered car with a monthly fuel cost of $219 at $3.85 per gallon.

        SDG&E is part of a 42-utility partnership with the Electric Power Research Institute and General Motors to advance plug-in hybrid electric vehicles.  The collaborative is working to accelerate large-scale deployment of plug-in hybrid electric vehicles and create a blueprint for an electric fuel infrastructure.  The collaborative also is addressing issues that ensure safe and convenient vehicle charging, public education, and public policy requirements to enable a smooth introduction of plug-in hybrid electric vehicles as a transportation alternative to conventional vehicles.

        SDG&E is addressing the San Diego region’s growing interest in a variety of safe, alternative electric and natural gas transportation technologies.  As part of its commitment to reduce greenhouse-gas emissions from its own fleet vehicles by about 15 percent by 2012, SDG&E will replace its passenger vehicles with hybrid-electric and compressed natural gas vehicles, and implement a fleet-efficiency and optimization program aimed at improving fuel efficiency and driving habits.

        To learn more about SDG&E’s Clean Transportation Program, visit

        SDG&E is a regulated public utility that provides safe and reliable 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.  The utility’s area spans 4,100 square miles.  Exceptional customer service is a priority of SDG&E as it seeks to enhance the region’s quality of life.  SDG&E is a subsidiary of Sempra Energy (NYSE: SRE), a Fortune 500 energy services holding company based in San Diego.

# # #