A quick carbon calculation

Hi everyone,

I can report that both the Leaf and the Volt are still performing perfectly.  They are both an example of outstanding engineering, given the state of battery technology, etc.

Since we have done this ‘experiment’ of driving only EVs for over a year and half, I thought it a good time to look at our carbon footprint result. Carbon Dioxide (CO2), one of the major culprits in the climate change disaster, is an invisible gas… an invisible pollution.  It is very difficult for any of us to get our heads around what we are preventing/saving/controlling when it comes to something like CO2.

To Volt does an excellent job of showing you calculation of the estimated gallons of gas saved, as well as a carbon calculation.  Based on those screens, by driving the Volt we have prevented about 12,974 pounds of CO2 from going into the atmosphere. I think they are able to relate that pretty clearly, since the Volt also has the gasoline electric generator system, so the Volt driver is still occasionally buying gas when on long trips, etc.  Note, we generally use only electric mile son the Volt (probably 93+% of the time), except when gong to places like North Carolina. While we still charge daily on those trips, by staying at EV friendly hotels and plugging in each night, we still use some gasoline.

The Leaf, being all electric, is a bit more difficult to compare.  You essentially emit no direct CO2 from the car itself.  Of course, charging EVs using the grid provided electricity still contributes some air pollution from the centralized power plants.  That depends on what type of fuels or mixes of alternative energy, etc.

But generally, the calculation is as follows (to the best of my current understanding):

Assumption – the EPA says the average passenger car goes 10,500 miles a year and gets 28 mpg.  They calculate that on average each gallon of gasoline burned puts out 18 pounds of CO2.

We have driven about 14,000 EV miles on the Leaf, so diving by 28 mpg gives us an estimated 500+ gallons of gas saved.  Take 500 gallons * 18 pounds of CO2 per gallon = 9000  pounds of CO2.

So both cars combined have prevented about 23,000 pounds of CO2 from going in the atmosphere.  But what does that mean? I can’t see it the gas… and its effects are accumulating with a lot more CO2 in the atmosphere from the other 8 billion people.  What does it mean?

hiking in forest in NCWell, there is a great website called American Forests that has a page that calculates the equivalent number of trees that a savings of CO2 relates to.  The US Forest Service calculates that an acre of trees holds about 50.8 metric tons of CO2, or about 911 pounds per tree.  So we take the 23,000 pounds / 911 pounds per tree = 25.24 trees.

Now that of course would be mature trees – and not just that.  That would have to be new trees planted and grown to maturity, and maintained somehow forever, since we started driving the Leaf and Volt.  So to sequester the carbon, the tree could be encapsulated in glass or sealed somehow and dropped into the bottom of the ocean or in a deep mine.  Somewhere where the carbon could NEVER NEVER NEVER be released.  So you can see, it is way better to NOT emit the CO2 in the first place.  We must always remember that we are burning the ancient forests, the ancient biosphere, every time we burn a gasoline today.

Anyway, we continue  to love driving the EVs and are now seriously looking at ways to get solar energy on our roof.  So our EVs will be charged using the sun :)   More on that later…