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HybridCenter Mailbag: Offroading & Plugging in
11/30/05

Here are a couple more good questions, and our attempt at good answers answers, that we think would be of broader interest.

Q: The Toyota brochure specifically states that the 4wheel drive Highlander hybrid is not intended for offroad use but the brochure does not state why this is so. I have seen comments on webboards that the highlander hybrid should not be used offroad because it has a separate electric motor for the rear axle and that motor might be damaged by driving on bumpy roads, by driving through deep snow, or by driving through puddles, or even by rocks from gravel roads. Are any of those statements correct?

A: While we recommend you contact Toyota directly to verify, our understanding is that the same statement is made in the conventional Highlander brochure.  It has nothing to do with the hybrid system, but rather the statement is to note that it is not a Jeep-like vehicle designed for heavy duty off-roading.  Both the conventional and hybrid highlander can go on dirt roads, snow, etc, but Toyota accepts no liability for people trying to treat either vehicle like a Jeep Rubicon.  Indeed, we found the following statement on Toyota's website:

"Highlander Hybrid in 2WD or 4WD is not designed to be driven off road...Toyota Highlanders are designed to meet most off-road driving requirements. Abusive use may result in bodily harm or damage. Toyota encourages responsible operation to protect you, your vehicle and the environment."

Q: The UCS piece on the Technology and Potential of Hybrid Vehicles you authored is excellent, but doesn't discuss the advantages of including connection to the grid for increasing the fuel efficiency of using hybrids for commuting by charging at night when utility rates are at their lowest and power is readily available.

A: Plugin hybrid technology definitely is one to watch, but the jury is still out.  There is no doubt that allowing a hybrid to connect to a clean power source to recharge the battery has the potential to improve its overall performance (our report, A New Road, estimated plugin hybrid technology at being able to achieve 70-80 mpg).  However, the benefits of using the electrical grid depend on three things:

• How clean the electricity is—about one half of U.S. electricity is generated from coal.  Using dirty sources of electricity to recharge a plugin can cause just as many, or more, problems than plugging in solves.
• How often consumers actually plug them in—if consumers do not regularly plug their vehicles in, the fuel economy could actually end up worse due to the extra weight of the batteries.
• When they plug them in—charging during the peak of the day could stress infrastructure and lead to increased pollution.  Ideally, consumers would plug them in regularly and only at times of lowest electricity use, but there’s no guarantee of either. 

The additional batteries and larger motor needed to make plugin hybrids are also another fiscal burden that would add to the sticker price.

That said, the potential of plugins cannot and should not be ignored.  A future of hybrids, whether plugins or conventional, running on clean, renewable fuels made in the U.S.A. is appealing enough to merit just as much attention as fuel cell vehicles.

More mail soon...

Posted by: ScottN 11/30/05

Original post and comments can be found on Hybridblog.org.