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Plug-In Hybrid Electric Vehicles

Fuel for our gas- or diesel-powered vehicles costs much more per mile than the power needed for an electric vehicle. Electric vehicles are also clean, quiet, largely independent of imported petroleum, and can be powered using wind generation or another source of renewable electricity.

A roadblock to success for electric vehicles has been their limited range. With hybrid-electric technology, however, that roadblock can now readily be overcome. Add extra batteries to a hybrid electric vehicle (HEV) and a way to "plug them in" and you can drive most of a typical day's mileage on clean, less expensive electricity, but still have an easily refillable fuel tank for longer trips. Some HEVs have already been converted to plug-ins and Mercedes-Benz is now making limited numbers of a demonstration plug-in Sprinter van.

Probably the biggest challenge plug-in hybrids have is the cost and weight of batteries. NREL is extensively researching thermal management, modeling, and systems solutions for energy storage technology. Even at today's battery costs, however, plug-ins may be able to repay their costs within a few years. NREL scientists and engineers also research improved power electronics critical to hybrid efficiency and conduct sophisticated modeling and analysis essential to showing the economic viability of plug-ins and identifying key areas for improvement.

NREL researchers are also seeking to carry the plug-in hybrid concept a couple steps farther by making the plug-in reversible. Called a "vehicle-to-grid" or "V2G", such a two-way plug allows the home and vehicle owner and local utility to take advantage of the extra electrical storage capacity in the vehicle batteries to meet peak demand, provide grid support services or respond to power outages. In addition, utilities pay premium rates for peak and backup power and might pay commuters to plug their vehicles in while at work to ensure their employer has high quality power throughout the day. NREL transportation analysts are quantifying the potential value of such systems.

Next Steps: Renewable Energy Communities

Another next step is for a plug-in based renewable community (PDF 640 KB). Download Adobe Reader. Drive home and plug your car into a house that requires little or no electricity and gets most of what it does need from renewable sources. Such "zero-energy homes" are readily available today-wouldn't whole communities of them together with plug-in hybrids be the perfect model for the future? NREL researchers are promoting the renewable community concept and doing the analysis and research needed to show their feasibility and outline their optimal design.