A Primer About Plug-In Hybrids

June 14, 2008 lacarguy Concept Vehicles, Hybrid Vehicles, LAcarGUY Sustainability 1 Comment

A Primer About Plug-In Hybrids

How would you like to run your car for less than $1 per gallon, with much lower emissions? Impossible?

Not according to Dr. Andy Frank, Professor of Engineering at the University of California at Davis, and Felix Kramer of The California Cars Initiative (CalCars). Frank and Kramer have become the world’s leading advocates for "gas-optional" or “plug-in” hybrid electric vehicles (PHEV).


Ironically, just when the American public is finally getting that you don’t have to plug hybrid cars in, here comes the plug-in hybrid. With the plug-in hybrid, you still will not be required to plug the car in—but you’ll have the option. As a result, drivers will get all the benefits of an electric car, without the biggest drawback: limited range. You'll be able to go all-electric for the vast majority of your driving, which for most motorists takes place close to home. When the electric charge runs out, a downsized gas engine kicks in and your car drives like a regular hybrid.


Staying in Stealth Mode

Many hybrid car drivers enjoy keeping the car in all-electric “stealth” mode, when the car is in slow stop-and-go traffic. Plug-ins would extend the stealth mode for the lion’s share of local driving.

The potential advantages are enormous. Consider:

·         A hybrid gets about twice the fuel economy as a conventional car of the same size and capacity

·         A plug-in hybrid will get about twice the fuel economy of a “conventional” gas-electric hybrid

·         A plug-in hybrid, running on biofuel (e.g., 85 percent ethanol) could almost entirely eliminate its use of petroleum


What are the naysayers saying about plug-in hybrids? And how do Frank and Kramer respond?



“The extra batteries will weigh too much.”

Response: The extra weight of the batteries will be offset somewhat by the reduced weight of the gas engine. At high speeds in particular, fuel efficiency is affected primarily by aerodynamics—the added weight of the equivalent of one or two additional passengers has minimal impact on mileage.


“The extra batteries will cost too much.”

Response: If sold in high volumes by carmakers, more powerful and cheaper nickel metal hydride or lithium ion batteries could be sold at prices only a few thousand dollars above that of today’s hybrids. Recharging will take place mostly at night during cheaper off-peak hours. Counting purchases, fuel and service, total lifetime cost of ownership will be lower than a gas car.


“Producing power from the grid (to charge the cars) will produce additional emissions.”

Response: What the industry calls "well-to-wheel" emissions (including greenhouse gases) for grid-powered vehicles is far lower than gasoline, even for the American power grid (which is about 50 percent coal). Cars charging off-peak will use power from plants that can't turn off at night. Many parts of the country get most of their power from cleaner sources such as natural gas and hydropower. It's far easier to improve centralized power stations than millions of aging cars. Finally, plug-in hybrids recharged from rooftop photovoltaic systems would have virtually zero emission.


Future Benefit of Vehicle-to-Grid Connection

Some day, the larger battery packs used in plug-in hybrids could juggle power back and forth from the car to your household current. If adopted on a widespread basis, a fleet of plug-in (a.k.a. "gridable" hybrids) could offer regulatory services [vakg1] to a modernized electric power grid. It is estimated that what's called “vehicle-to-grid” or "V2G" could benefit individual car owners by as much as $2,000 to $3,000 per year for the use of their energy storage capacity—offsetting their purchase and operating costs.


Will Auto Makers Produce Plug-in Hybrids?

Despite a number of announcements from leading car companies, and some exciting concept vehicles shown at auto shows, plug-in hybrids are not yet available.   That could change in 2009, when General Motors promises the introduction of a plug-in hybrid version of the Saturn Vue SUV.  Soon after, GM expects to introduce the Chevy Volt plug-in hybrid.  Industry analysts expect Toyota to introduce a plug-in Prius in the next few years.

[vakg1]I’m not sure what you mean by this. “Regulatory” to me sounds like PUC, and regulation – rather than what I think you mean, which is the ability to push current back into the grid and regulate demand by perhaps creating more capacity at peak demand times. Regardless, I would reword to avoid confusion if possible.


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