Clean Power For Electric Cars
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Written by Paul M. Gandee
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Tuesday, 14 July 2009 |
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Regarding the May 5 editorial, "A yellow light for electric cars": I was surprised to read the questions raised by this editorial regarding plugin hybrid electric vehicles (PHEVs). Specifically, whether electric utilities will be able to build enough power to charge the vehicles and whether the environmental benefits of PHEVs will be negated when the vehicles are charged from electricity generated from fossil fuels?
The Electric Power Research Institute (EPRI) and the Natural Resources Defense Council (NRDC) answered these and other important questions regarding widespread deployment of PHEVs in a landmark analysis published in July 2007. That study, the most comprehensive analysis on the subject to date, models the penetration of new vehicles (allowing new vehicle technologies to enter the market and replace older vehicles over time) in parallel with the continuous evolution of new, cleaner generation in the electric sector.
In the nominal yet aggressive scenario, the additional electricity demand attributable to the vehicles is 8 percent, requiring a capacity expansion of 3 percent. Why is there such a large discrepancy in these results with those cited in the Britain? The British study assumed that all 27 million petroleum drive vehicles in the country would immediately be transformed into full electric vehicles with half of them charging simultaneously overnight.
By contrast, in the nominal scenario of the EPRI-NRDC study, PHEVs account for 62 percent of the vehicle fleet by 2050, and are assumed to charge primarily but not exclusively at night at a lower rate than assumed in the British study. To place the British results in context, if we could have 10 million PHEVs materialize overnight in the US today, electricity demand would increase by less than 1 percent.
The environmental benefits of PHEVs are similarly impressive. Even when charging solely from older, coal fired power plants, the CO2 footprint of a mile driven by electric power is 30 percent less than a conventional gasoline vehicle. Of course, electricity used to charge PHEVs will come from a variety of generation technologies including coal, natural gas, nuclear and renewable sources and these technologies are improving in their environmental performance and efficiency over time.
As a result, the EPRI-NRDC study found that in 2050 PHEVs will lead to a net decrease in CO2 emissions greater than 450 million metric tons, equivalent to avoiding the carbon emissions from more than 80 million vehicles on the road today. In addition, petroleum use in the US would decline by nearly 4 million barrels per day.
There will be no overnight transformation to electric drive. However, it is clear that the road ahead for PHEVs has a "green" light.
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Last Updated ( Tuesday, 14 July 2009 )
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