Carnegie Mellon Study Finds Plug-In Hybrids Cost Inefficient

By dancurranjr On March 12th, 2009

2011 Chevrolet Volt Production Show CarA Carnegie Mellon study found that plug-in hybrids with large battery packs (40 miles or more) will never allow the owner to recoup the initial price premium.

Professor Jeremy J. Michalek and researchers Dr. Constantine Samaras and C.-S. Norman Shiau report that plug-in hybrids with small battery packs may be the best option for saving drivers money.  In an article to appear in the journal Energy Policy, the authors find that urban drivers who can frequently charge their vehicles (every 20 miles) can reduce gas consumption, greenhouse gas emissions, and expenses with a plug-in hybrid with a battery pack sized for about seven miles of electric travel.

This comes as a blow to Chevrolet’s upcoming Volt plug-in hybrid as it allows the driver to travel 40 miles on one charge before the gasoline generator fires up to recharge the batteries.  General Motors chose 40 miles as the target range because most people travel less than 40 miles in one day.  “Forty miles might be a sweet spot for making sure a lot of people get to work without using gasoline, but you’re doing it at a cost that will never be repaid in fuel savings,” said Michalek.

Extending the electric only range of vehicle travel comes with a variety of penalties including added weight and expense.  The Chevrolet Volt’s battery pack weighs 400 pounds and may cost around $16,000- more than some small cars sell for today.  The added cost of the batteries necessary for 40 miles of travel are part of the reason the study suggests a smaller, lighter battery pack capable of powering a car for 7-10 miles is the best option to save drivers money.

In addition to questioning a 40 mile electric range, some analysts are questioning hybrid-electric vehicle’s battery lifespan.  K.G. Duleep, managing director of consulting firm Energy & Environmental Analysis Inc. in Arlington, Virginia, and a researcher on a U.S. study on plug-ins and other advanced autos, said he is very skeptical about the lifespanof the batteries.  “I’m very skeptical about the prospects for near-term durability of the batteries.  Even in the lab they aren’t lasting more than seven years,” said Duleep.

With more automakers planning to offer plug-in hybrids in the near future, only time will tell if consumers are willing to pay the premium for a greater electric operating range.  Ford and Toyota are both planning to offer plug-in hybrids in the near future and GM will be releasing a plug-in version of its Saturn Vue as well.

SOURCE: AutomobileMag

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