Plug-in Hybrid Electric Vehicle

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Plug-in hybrid electric vehicles (HEVs) are hybrid cars with an added battery. As the term suggests, plug-in hybrids - which look and perform much like "regular" cars - can be plugged in to a 120-volt outlet (for instance each night at home, or during the workday at a parking garage) and charged.

   1. Description

   2. Why

   3. How

   4. Future Trends

   5. Related Links

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PHEVs have the potential to dramatically decrease petroleum fuel consumption and improve energy efficiency. The PHEV R&D Plan is driven by the desire to reduce dependence on foreign oil by diversifying the fuel sources of automobiles.Some universities, companies and entrepreneurs in the private sector also have promoted plug-in hybrids as a way to substantially realize the benefits of electric vehicles without the range limitation (the primary impediment to mass market electric vehicles).In addition, some electric utilities are interested due to the potential to utilize off-peak capacity and increase their long-term demand base.


Need for a substantial improvement over today’s hybrid vehicles that are capable at most of only a few miles electric range at reduced performance. In addition, consumers currently pay a premium for hybrids.Additional electric range, requiring a higher energy battery and higher power electric drive components, will have to be accomplished without further exacerbating the cost differential – to increase the likelihood of high volume sales and consequently the intended fuel savings.

  • PHEVs can substantially reduce petroleum consumption, but cost is the primary impediment and battery technology is a potential show stopper for production.

  • Electric power generation efficiency and the environmental impact of automobiles can be improved by shifting to electricity from gasoline;

  • Off-peak power can handle a large number of PHEVs, i.e., power from the electric grid is not a barrier.

  • Fuel economy, rather than all-electric range (AER) is the key vehicle efficiency metric for the public;

  • All other vehicle aspects must be competitive, including vehicle purchase and operating costs, for a PHEV to be marketable.

Environmental impacts of plug-ins should be compared with those of conventional vehicles on the basis of emissions over the entire fuel-cycle ("well-to-wheels",) meaning the emissions associated with the extraction, processing, distribution and final use of the energy that propels the car.While for conventional vehicles these include emissions that result from extracting and processing crude oil as well as tailpipe emissions, for plug-ins we must take into consideration emissions produced by power plants providing the electricity for charging the vehicles' batteries.All told, a plug-in that is fully charged every night can reduce emissions by 50% due to the improved fuel economy and the non-production of tail pipe emissions during the electric driving phase.


The U.S. Department of Energy (DOE) is supporting the development of hybrid vehicles with the ability to operate in both electrical/mechanical and electric-only modes recharging from a standard electric outlet because of the potential national benefits of substantially shifting fuel from petroleum to electricity.PHEVs and fully electric cars may allow for more efficient use of existing electric production capacity, much of which sits idle as operating reserve most of the time.

  • Vehicles are charged primarily during off peak periods (i.e., at night), or equipped with technology to shut off charging during periods of peak demand.

  • Advantage of a plug-in vehicle is their potential ability to load balance or help the grid during peak loads.

  • This is accomplished with vehicle to grid technology.

  • By using excess battery capacity to send power back into the grid.

  • Then recharge during off peak times using cheaper power, such vehicles are actually advantageous to utilities as well as their owners.

Even if such vehicles just led to an increase in the use of night time electricity they would even out electricity demand which is typically higher in the day time, and provide a greater return on capital for electricity infrastructure.

Electricity instead of gasoline

Most of the energy used by plug-ins comes from electricity and not from gasoline.

  • Unlike in the 1970s, when much of our electricity was generated from oil, today only 2% of our electricity is generated from oil.

  • The plug-in hybrid drive system is compatible with all vehicle models and does not entail any sacrifice of vehicle performance or driver amenities.

  • A mid size plug-in can accelerate from 0 to 60 miles per hour at less than 9 seconds.

  • They can sustain a top speed of 97 mph and maintain 120 mph for about two minutes even with a low battery.


Plug-ins estimated retail price is higher than that of corresponding conventional vehicles. The difference in price depends on the size of the battery. Every additional 10 miles of vehicle range in electric mode adds about $1,000 to the cost.Battery costs are the primary reason for this incremental cost, and battery prices are likely to fall with increased production. The price difference is partly offset by lower operating costs of plug-ins.Fuel costs for conventional vehicles stand on 6 cents per mile while for plug-ins the cost is only 3 cents per mile including the cost of electricity.

Future Trends

Plug-ins run on the stored energy for much of a typical day's driving - depending on the size of the battery up to 60 miles per charge, far beyond the commute of an average American - and when the charge is used up, automatically keep running on the fuel in the fuel tank.PHEVs have been sold as commercial passenger vans, utility trucks, general and school buses, motorcycles, scooters, and military vehicles. Hybrid Electric Vehicle Technologies, Inc converts diesel buses to plug-in hybrids, under contract for the Chicago Transit Authority.An AER requirement would drive cost up and decrease the likelihood of production. Federal government is expected to set policy, support pre-competitive research, act as a trusted source of information and minimize market barriers for PHEVs. 


PHEVs, AER, U.S. Department of Energy, Fuel Crunch, Plug-in Hybrid Electric Vehicle, Gas-Optional Hybrids.

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