Thursday, May 29, 2008

Plug-In Hybrid Electric Vehicle Benefits

Plug-in hybrid electric vehicles (PHEVs) promise many benefits for consumers, fleets, and the nation. These advanced vehicles have the potential to cut fuel use and costs, increase U.S. energy security, protect public health and the environment, and enhance the U.S. electrical system. Government and industry research and development are overcoming the barriers to realizing these benefits.

Cutting Fuel Use and Costs

Electricity typically costs much less than gasoline or diesel fuels. Because PHEVs use electric power much of the time, and the batteries are recharged by plugging into the electrical grid, they can significantly reduce fuel use and costs. For example, if electricity costs $0.08 per kilowatt-hour and gasoline costs $2.77 per gallon, a PHEV could drive on electric power for 3 cents per mile compared with 13 cents per mile for driving on gasoline. Combined operation might result in a cost of about 6 to 8 cents per mile.

Plug-in hybrid electric vehicles also offer flexible fueling options. Because PHEVs can be recharged at home much of the time, drivers can limit their trips to the gas station.

Increasing Energy Security

The United States imports more than 60% of its petroleum, two thirds of which is used to fuel vehicles in the form of gasoline and diesel. The demand for petroleum imports is increasing. With much of the worldwide petroleum reserves located in politically volatile countries, the United States is vulnerable to supply disruptions.

Plug-in hybrid electric vehicles are highly efficient—requiring little petroleum-based fuel to drive—and can use electricity derived from domestic fossil fuel, nuclear, and renewable sources. PHEVs also could be designed to use renewable and domestically produced alternative fuels instead of gasoline or diesel, further reducing U.S. reliance on imported petroleum.

Protecting Public Health and the Environment

Electricity is an energy carrier rather than a primary energy source. Thus, the environmental benefits of PHEVs depend in part on the source of electricity from which the PHEVs are charged. If the electricity comes from efficient power plants, the benefits can be substantial. One U.S. study projected an average 42% carbon emissions reduction from mileage driven on electricity instead of gasoline. Even transferring the point of emissions from the tailpipe to the power plant could be important for urban areas with severe automobile-related air quality problems.

Hybrid vehicles have additional features that make them more environmentally friendly than conventional vehicles. See Hybrid Electric Vehicle Benefits to learn how hybrid systems reduce pollutant emissions.

Enhancing the Electrical System

Plug-in hybrid electric vehicles have the potential to enhance the nation's electrical generation and distribution system. Electrical demand varies greatly; demand is generally high during the day and low at night. Charging PHEV batteries at night would take advantage of the low demand. If vehicle-to-grid capabilities are developed, PHEV battery capacity also could be used to help meet peak electricity demands. PHEV drivers would charge their vehicles while demand and electricity prices are low and, when their vehicles are idle, sell electricity back to the utility when demand and prices are high. This could help utilities avoid building extra generation capacity to meet peak demands.

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