How to Calculate Your Car’s Carbon Footprint & Why All Cars Get 7.1 “CPG”

cotap license plateCalculating your car’s carbon footprint is very straightforward. Burning one gallon of gasoline emits 19.4 pounds of CO2 (22.2 for diesel), so all you need to know is your average miles per gallon (mpg), number of miles driven, and number of pounds in a metric tonne (2,204.62).

As an example, if you drove 10K miles in a year and averaged 25 mpg then your car’s carbon footprint calculation would be as follows: 10,000 ÷ 25 = 400 gallons. 400 gallons x 19.4 pounds = 7,760 pounds. 7,760 pounds ÷ 2,204.62 pounds per tonne = 3.52 tonnes. That’s the result you’ll get when entering 10K miles and 25 mpg in our carbon footprint calculator.

Your Car’s Carbon Footprint is HALF the Story…

COTAP is built a little bit differently than other carbon offset providers. To us, all unavoidable carbon emissions represent an opportunity to create life-changing income for the world’s poorest people. So, we see burning a gallon of gas not only in terms of carbon emissions, but also as an opportunity to improve rural livelihoods through supplemental income.

Weird but true, driving a car can generate wages (measured in cents per gallon or “CPG”) just as it generates emissions… when those emissions are offset via COTAP. It is more indirect and happens on a different time scale, but the connection is just as real. Doubt that? Watch this…

Calculating CPG

There are two reasons we can assert this: 1) COTAP’s consistent, modest, and transparent pricing of $15 per tonne and margin of 10% and 2) The Plan Vivo Carbon Standard’s requirement that projects share a minimum of 60% of carbon revenues with participating communities. It is important to note that COTAP has exclusively supported Plan Vivo projects since our founding in 2011, and that all Plan Vivo projects are located in typically remote areas of least developed regions where incomes are less than $2 per day.

Here’s how we arrive at the CPG calculation using the example above (10K miles and 25 mpg). First, COTAP creates $8.10+ in community income per tonne offset through us ($15 – 10% margin = $13.50 x 60%+ = $8.10). This amount that reaches the poor through COTAP is often considerably greater than many providers charge for the entire tonne (a project can’t pass on $8.10 per tonne to communities if they’re only receiving $5.00 per tonne). So, driving a car 10K miles and averaging 25 mpg generates 3.52 tonnes. That multiplied by $8.10 per tonne equals $28.51. To get CPG, divide $28.51 by 400 gallons and the result is (a minimum of) 7.1 cents per gallon.

You may notice CPG stays the same regardless of a car’s efficiency or number of miles driven. That’s because it’s essentially calculated only using COTAP/Plan Vivo’s revenue share and the carbon content of a gallon of gas. Another, more simple way to express this is $8.10 income per tonne x .0088 tonnes per gallon (19.4 ÷ 2,204.62) = 7.1 CPG.

CPG is Neat, But Driving Less & Increasing MPG Are The Goals

Cents per mile (CPM) would be a different story. As mentioned above, every car can generate 7.1 CPG; however, CPM takes fuel efficiency into account and thus a less efficient car with lower mpg would actually generate more CPM. So, pursuing higher CPM by driving a less fuel efficient vehicle, or by driving more, would be the wrong kind of tradeoff!

We’re not here to proselytize about car choice, rather it’s to connect the dots between offsetting unavoidable CO2 emissions and the potential that creates in terms of direct economic benefits for the poorest. At the end of the day, the truth is that we should be moving rapidly towards a world where every car’s CPG is zero… because it doesn’t burn gasoline.

Internal Combustion Engines and The Big Picture

Gasoline-burning cars are going to be around for the foreseeable future, even as electric vehicle charging networks proliferate, as EV ranges increase, and as battery prices come down. Also, it can be argued that EV’s are still largely too much of an inaccessibly-priced status symbol, and too much efficiency innovation (in terms of Miles per kWh) continues to be wasted on the persistent, inane obsession with SUV’s and acceleration specs… the same as it was with ICE’s.

Although it’s frustrating to watch history repeat itself in some ways, much progress is being made. For now, the priorities should be driving less and reducing your emissions from driving (we have lots of tips on how to do that. And if, you like the idea of generating CPG when offsetting your emissions from driving, you are more than welcome to become a Cotapper.

(This is a refurbished version of a vintage COTAP blog post originally published in November 2011.)

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