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Green Car Rankings, an Overview

Green Cars, More Complex than You Think
Green Cars, More Complex than You Think

Wait, don’t jump the gun and says, “solar electric” is the green car with the best carbon dioxide emissions. Well, you’re right, but bear with me, it’s a little more complicated than that.

Lifecycle emissions, even for green cars, include manufacturing, recycling, as well as fuel extraction and refining. For electric vehicles, you’d have to include power production emissions. After all, although and electric vehicle emits no emissions on its own, it still needs to get energy from somewhere. Even solar panels have their associated emissions. What happens when you crunch all the numbers, say, for four conventional vehicles and one electric vehicle on four different power grids?

For this comparison, we consider four generic gasoline-powered conventional vehicles, whose fuel economy range from 20 to 50 miles per gallon (mpg). Unsurprisingly, at 20 mpg, lifecycle carbon dioxide emissions amount to 589 g CO2/mi (grams carbon dioxide per mile), this is the most heinous of the group. You can drive an electric vehicle, in this case the 29 kWh/100mi (kilowatt-hours per 100 miles) Nissan Leaf, recharge it on a coal-fired power plant, and still emit less carbon dioxide than a 20 mpg conventional vehicle, or 416 g CO2/mi.

This is where things start to get sketchy when comparing these green cars, the electric vehicle its fuel-sipping conventional counterparts. For example, while the electric vehicle, charging on coal, generates 416 g CO2/mi, the 30 mpg conventional vehicle, on the same road, generates 413 g CO2/mi, a difference barely worth mentioning. Stepping up to charging your electric vehicle on an oil-fired power plant, the electric vehicle generates 349 g CO2/mi, and the 30 mpg gasoline-powered vehicle at her side generates 326 g CO2/mi, another difference barely worth mentioning. The results are similar, comparing an electric vehicle charging on natural gas and a 50 mpg conventional vehicle, 257 g CO2/mi and 273 g CO2/mi, respectively. Although, to be certain, related natural gas extraction emissions could be far higher than anyone ever thought.

Really, the only way to make a significant cut in you carbon dioxide emissions, a truly green car, is to charge only on solar power, which makes this electric vehicle responsible for a mere 127 g CO2/mi.

Image © ShrinkThatFootprint.com

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  1. LoneWolffe GaspardB  Hopefully, Yes.  But I’ve painfully come to realize, that there are “factors” that defy logic, even economics and the overall “health” of the earth.  If you are NOT participating in this factor, it may be difficult, if not impossible to see.

    Other Factors by Example:
    Bill Russell played basketball at USF winning 2 NCAA titles in 3 yrs.  Boston traded it’s All-Pro center for the rights to draft Russell.  Even with their existing All-Pro center, Boston had not made the playoffs.  When Boston acquired Russell, they subsequently began the “Dynasty” with only that one personnel change in the starting lineup.   Though Russell was the only constant of the Dynasty, Boston won 11 NBA titles in 13 yrs, each year with 4 varying support players.  Yet, Russell did NOT win Rookie of the Year (due to other “factors”).  

    I give credit to Rudolph Diesel for an important innovation that has literally ruled commercial transportation.  His innovation, once completely adapted to domestic vehicle transportation, could represent a tremendous challenge to 100 year old petroleum thinking.  Not to mention potentially saving the planet by reducing oil extraction and consumption – If John D. and Fred C. were around today, I think they would, at least, be able to see (and more importantly act) more responsible,

  2. GaspardB  Of course, if you were going for the best-case-scenario, then EV on PV would be all win, perhaps even EV on Hydro. Still, it’s worth noting the differences in emissions when you consider the alternatives. In some places, you’d be better off buying a good 30- or 40-mpg vehicle instead of an EV.
    Hopefully, renewables will start taking over in more capacity, and knock out the fossil fuels, cleaning up the grid.

  3. GaspardB  I agree, Renewable is the way to go. By Definition:  Renewable energy is generally defined as energy that comes from resources which are naturally replenished on a human timescale such as http://en.wikipedia.org/wiki/Sunlight, http://en.wikipedia.org/wiki/Wind, http://en.wikipedia.org/wiki/Rain, http://en.wikipedia.org/wiki/Tidal_power, http://en.wikipedia.org/wiki/Wave_power and http://en.wikipedia.org/wiki/Geothermal_energy.

    I believe that “Veggie” fuel should be on this list.  Though not necessarily an automatically natural renewable, the effort to plant, harvest, replant, refine and distribute is economically sound.  It will create jobs along the lines of the existing, and very successful,  “fossil fuels” economic model.  Of course the entire cost of production will not rely on the AC grid, while replanting more than harvested, and naturally using sunlight, rain, and the earth (some irrigation in the West).  

    I take liberties with the term “renewable”.  Of course, ultimately I advocate solar, but I haven’t quite figured-out a “low-voltage ‘multiple’ DC engine/motor” EV configuration, as I feel solar is best suited to  low voltage DC.

  4. Great analysis, very important to note that an electric car using electric from the conventional grid trasfers emmisions form the tailpipe to the coal burning facilitiy. BUT it doesn’t have to be that way – Renewable for the win!

  5. Coal, Natural Gas, AC Grid all require the same LifeCycle analysis which involves drilling and mining.  It’s taken more than 50 yrs to put L.E.D.s in automobiles, yet they used fiber optic light illumination transfer (from the dashboard to the fender) in the 1960’s because they didn’t know what else to do with fiber optics – well they figured it out.  A single optic fiber will transmit the entire Encyclopedia Britannica 3 x per second.  That’s a quantum leap from light illumination transfer to digitized data transfer.

    Diesel technology represents the same potential advancement.  As a veggie fuel based generator, lifecycle production of veggie fuel will return most of it’s impact in today’s world, but in the future it should yield a positive return as technology improves.  Remember, the Cadillac ELR incorporates an on-board gasoline generator.  The vehicles gasoline generator extends the driving range of the EV by the amount/size of the on-board gasoline tank.  By increasing the on-board tank capacity, and using an on-board “diesel” generator using 100% veggie fuel, the configuration could yield astounding driving range,  This is all “off-the-self” technology.


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