| Plug-in Hybrid Electric Vehicle (PHEV) Information |
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Plug-In Hybrid Electric Vehicle
Benefits
Plug-in hybrid electric vehicles promise many benefits for consumers, fleets, and the nation. Plug-in hybrid vehicles that can recharge from wall-plug energy offer high fuel economy and the potential to reduce petroleum use. 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.
Emissions
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.
Manufacturing
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.
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.
The national and global benefits of PHEVs are greatest when the electricity used to power them comes from clean, renewable sources. If vehicle-to-grid capabilities are developed, PHEVs could help compensate for the intermittency of renewable energy production. For example, wind-generated electricity could be stored in PHEV batteries when the wind is blowing and demand is low and drawn out when the wind slackens or demand is high. A National Renewable Energy Laboratory report calculates that, if half of U.S. vehicles were PHEVs, wind turbine electrical generation would double.
Safety
Advanced batteries are part of the hybrid system, and they have a limited number of charging cycles (the number of times the battery can be charged and discharged). Today's hybrid vehicles come with excellent warranties, which include the battery packs. Check with the dealer about battery life and warranties.
PHEVs are very safe vehicles. They undergo the same rigorous testing as conventional vehicles and must meet all of the same standards for safety, including crash testing and airbags.
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.
Availability
Several barriers are preventing widespread commercialization of plug-in hybrid electric vehicles including the following:
- Hybrid component mass, volume, cost, reliability, and safety
- Lack of domestic sources for batteries
- Consumer behavior and expectations
- Robust operation in range of environmental conditions.
Government and industry research and development efforts are aimed at overcoming these barriers. Because PHEVs require far more battery capacity than regular hybrid electric vehicles, battery technology is particularly critical. To make PHEVs more cost competitive, batteries must be cheaper, lighter, and longer lasting. The U.S. Department of Energy (DOE) is supporting research and development on batteries as part of its Vehicle Technologies Program. Complementary research on power electronics includes motor controllers and current converters and inverters that condition electrical power from the battery for the electric motor.
Plug-in Hybrid Vehicles in DAS Fleet
Source: US Department of Energy, Energy Efficiency and Renewable Energy, Alternate Fuels & Advanced Vehicles Data Center: http://www.afdc.energy.gov/afdc/
Updated: 02/20/2009
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