Plug-in hybrids v. conventional hybrids: New study shows benefits as well as losses

This article in the Christian Science Monitor reports on a recent study conducted by the American Council for an Energy-Efficient Economy (ACEEE) which examines the environmental benefits and costs of a plug-in hybrid when compared to a conventional hybrid. According to their figures, the results aren't as plainly evident as you may have thought.

First, the economics. By definition plug-in hybrids require a larger, beefier battery pack. That's how they achieve a decent electric-only range. And of course, as a consumer, you'd be paying for the privilege up front. The ACEEE estimates that the average time it will take the owner of a plug-in hybrid with a 40-mile electric range to begin to realize savings due to fuel costs is about 6.4 years while conventional hybrids recover their costs in about 3 years. Until battery prices significantly drop, this is one of those factors that we always expected (or at least we should have.)

Now, on to the environmental side of the examination. The report states that the impact of plug-in hybrid electric vehicles (PHEV) varies dramatically by region. For instance, a PHEV located in California would lower carbon dioxide (CO2) emissions by one-third compared to a conventional hybrid because of the low-pollution facilities generating electricity for the grid in the eco-friendly state. That same plug-in charged in the Midwest would hardly see any reduction in CO2 emissions, though the nitrogen oxide (NOx) levels would fall slightly. However, sulfur dioxide emissions which contribute to acid rain would quadruple.

Overall the gains and losses are still mixed. On a national average, the ACEEE found that CO2 emissions would be reduced by 15 percent with PHEVs, yet sulfur dioxide pollution would go up by 157 percent.

Therese Langer, ACEEE's transportation program director and coauthor of the report, notes the significance of the anti-optimism of the study in that it's dangerous to place full faith in any new technology without knowing the consequences. She says, "We want government policy based on reality, not overstating what [plug-in technology] can achieve and when."

As plug-in hybrids are relatively new to our landscape, this is just the beginning. There will undoubtedly be a lot more news, reports, estimates, debates and predictions and hopefully, they'll sprout some answers. This study should be seen as a wake-up call to get moving and clean the electrical grid as more cars in our near-future begin to use it as a source for energy.

[Source: Christian Science Monitor]

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