(Source:  GM’s Fast Lane Blogs, via TreeHugger )

GM Defends the Volt’s Design
A recent Carnegie Mellon University study (pdf) challenged the real-world gasoline savings and cost effectiveness of plug-in hybrids like the Chevy Volt. GM’s Vice President Global Program Management, Jon Lauckner, who has been involved in the Volt project responded on the company’s blog. Find out what he had to say below.

All-Electric Range

The first thing is the electric range of the car. Somewhat strangely, the CMU study found that “for urban driving conditions and frequent charges every 10 miles or less, a low-capacity PHEV sized with an AER (range) of about 7 miles would be a robust choice for minimizing gasoline consumption, cost and greenhouse gas emissions.”

7 miles? Really?

Well, Jon Lauckner responds:

I’ll cut to the chase; for starters, the study’s endorsement of plug-in vehicles with only a “token” electric-only range (seven miles) overlooks the inconvenience of recharging for the vast majority of drivers (approx. 90 percent) with a daily commute that exceeds seven miles. I mean, honestly, how many customers are going to stop every seven miles and wait at least 30 minutes (if a car has a high-capacity charger like the Volt with the same level of electrical energy to match it) for their battery to be recharged? […] And, if customers don’t recharge during the day, these “token” plug-ins will run primarily on gasoline. How is that consistent with reducing green house gas emissions and our dependence on petroleum?

Click here to read the entire article.

(Source: Carnegie Mellon University Design Decisions Laboratory)

PITTSBURGH— Carnegie Mellon University professor Jeremy J. Michalek and researchers Dr. Constantine Samaras and C.-S. Norman Shiau report in a new study that plug-in hybrid electric vehicles with small battery packs may be the best bet for saving drivers money while addressing U.S. dependency on foreign oil and global warming.

            In an article to appear in the journal Energy Policy, the authors find that urban drivers who can charge their vehicles frequently (every 20 miles or less) can simultaneously reduce petroleum consumption, greenhouse gas emissions, and expenses with a plug-in hybrid vehicle whose battery pack is sized for about 7 miles of electric travel per charge. In contrast, plug-in hybrid vehicles with large battery packs – sized for 40 or more miles of electric travel – are too expensive for fuel savings to compensate, even in optimistic scenarios.

            Plug-in hybrid vehicles use charged batteries to propel the vehicle partly using electricity instead of gasoline, which gives them potential to reduce petroleum consumption and greenhouse gas emissions. “Larger battery packs allow drivers to go longer distances on electric power. But batteries are heavy and expensive,” says Michalek. “We accounted for the effects of additional batteries on vehicle cost, weight and efficiency in order to understand the net implications on petroleum consumption, cost, and greenhouse gas emissions. Over a range of scenarios — including fluctuating gas prices, new battery technologies or high taxes on carbon dioxide emissions — plug-ins with small battery packs are economically competitive with ordinary hybrid and conventional vehicles for drivers who charge frequently.”

Click here to entire press release.