Saturday, July 28, 2012

Auto Enthusiastic!: How much CO2 is emitted to charge an EV?

Electric vehicles (EVs) are being given an energy consumption rating called MPGe (miles per gallon equivalent) by the EPA. This is so that consumers can easily compare the energy efficiency of these vehicles with conventional vehicles powered by gasoline or diesel.?

EVs are about 4 times more energy efficient than conventional vehicles ? in other words, they run on 25% of the energy needed by a gasoline powered car.





But, what about CO2 emissions? ?How much CO2 is emitted to produce the electricity used to charge an EV? You might think that it is 4 times less, since they are about 4 times more fuel efficient ? but it?s not so. Here?s why I say that:

MPGe explained

Miles per gallon gasoline equivalent (MPGe) is the energy consumption of hybrid and electric vehicles expressed as miles per US gallon. The EPA calculates the MPGe based on: (a) one gallon of gasoline being equivalent to 33.7 kWh of electricity, (b) the energy consumed by a vehicle during five standard drive cycle tests (the 5 cycle test) which simulates varying driving conditions. (For more info see EPA Car Label FAQs)

For example, an electric vehicle that uses 33.7 kilowatt-hours to drive 100 miles will use the energy equivalent of one gallon of gasoline and, therefore, would have an MPGe of 100 miles per gallon of gasoline equivalent.

Co2 emissions

(Please bear in mind that the following calculations are based on approximate figures)

On average, 44 pounds of CO2 is emitted when producing 33.7 kWh of energy at a power plant. An EV typically will travel about 95 miles on 33.7 kWh of energy, which means than the typical EV is responsible for about 0.463 lbs of CO2 per mile (44 divided by 95).

In contrast, gasoline emits about?19.4 pounds of CO2 per gallon consumed. The average MPG of new vehicles in the US in 2012 is 24, so the average car would emit about 0.808 lbs of CO2 (24 divided by 19.4).

Therefore, supplying an EV with electricity results in roughly 57% of the emissions of CO2 emitted by a gasoline powered car.

Of course, even less CO2 emissions will result if EVs can be charged with electricity sources from wind, hydro, or solar power.

To see what CO2 emissions are indirectly caused through charging your specific hybrid or electric vehicle in your area, visit fuel economy hybrids and EVs As always, I encourage you to post your questions and feedback in a comment and to share the post via Facebook, Twitter, Google+ or any other social site, if you find it informative and beneficial. Please check out another of my blogs: http://learninghowtomakealivingonline.blogspot.ie/

Source: http://www.autoenthusiastic.com/2012/07/how-much-co2-is-emitted-to-charge-ev.html

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