Published on February 2nd, 2019 | by Michael Barnard
February 2nd, 2019 by Michael Barnard
How much CO2 does a fleet of 15 cars emit? There are fleets of cars and there are fleets of cars. And there are locations and locations.
Where the cars are, how the fleets are used, and the type of vehicles in the fleet make a big difference. Let’s look at several scenarios and do the math.
A woman with a really big family
Suppose a woman has parents, kids, brothers and the like all living in the same sprawling compound, 15 adults who drive. And she owns all of the cars. They all drive 13,474 miles per year, the US average for almost exactly 200,000 miles total for the 15 cars.
The cars are pretty average, with about 28 miles per gallon EPA performance and they drive them sedately, so that they achieve that. The fleet will consume about 7,200 gallons of gas.
Each gallon of gasoline when run through an internal combustion car emits 20 pounds of CO2 directly, and then there’s the emissions related to petroleum extraction, refinement, and distribution which are another chunk. Let’s call it 25 pounds for round numbers.
The fleet will emit about 180,000 lbs of CO2, or 90 tons. Native Energy sells carbon offsets for $15.50 per ton, so that’s about $1,400 dollars.
However, these are normally used cars that get junked eventually. Let’s assume a fairly normal four year ownership cycle, so about four cars get replaced annually. Each car has about 17 tons of CO2 embodied or emitted during manufacturing. Perhaps 50% of that will be returned via recycling of components, so that’s another nine tons for each car, 36 tons in total or $560 in offsets.
Car hobbyist racer
The person drives them more than the average person drives cars. So instead of covering 13,474 miles, the US average per year, they cover 18,000 miles.
And they tend to drive cars with much worse mileage, performance cars and muscle cars, rather than cars with the US EPA average of 28 miles per gallon. And they tend to drive them harder, with both track days and trailering vehicles to track days. Let’s assume closer to an average of 14 miles per gallon.
That suggests that this car hobbyist would consume around 1,300 gallons of gasoline a year.
That gives a CO2 emission of 32,500 lbs or 16.25 tons. That’s about $250 dollars in offsets.
This assumes that the carbon embodied in the cars isn’t counted. Given that the cars are being driven a lot less than usual under this scenario, they are effectively taken off the road so that’s probably a wash. The majority of carbon emissions from internal combustion cars is from use, not from manufacturing.
Car collector of gas cars who barely drives them
Think Jay Leno. His daily driver is a Chevy Volt and he never buys gas, just running around town on plug-in hybrid electric battery power alone.
His collection of cars has the engines run and the wheels rolled a handful of times a year just to keep them in good working order, but they really just sit there.
Assuming his Chevy Volt driving of 11,000 miles without gas was typical for a year, he’s still traveled 11,000 miles. EVs average about 30 KWH per 100 miles, so that’s about 3,300 KWH of electricity. He lives in California, and let’s assume he gets his electricity from the grid. California’s grid is a lot cleaner than the US average at 427 grams or about .94 lbs per KWH. That’s about 3,100 lbs or 1.5 tons of CO2.
He probably gets another ton from turning his cars on and occasionally driving some of them. That brings it up to 2.5 tons or about $24 in offsets.
Electric car collector
This person really loves electric cars. They own a couple of every Tesla ever built. They own a couple of Nissan Leafs. They own a Chevy Bolt or two. They are really upset that they lost while bidding for the EV1. They have a 1900 electric car.
Their daily driver is a Tesla. They drive the average miles per year, 13,474, and they live in a completely average US state where the CO2 per KWH is the weighted national average of 1.6 lbs. They emit about 6,500 lbs or around 3 tons of CO2 per year. That will cost them about $47 in offsets.
Once again, with the carbon in the cars just sitting there, let’s not consider the annual offsets. This is a bit more challenging to accept however, as they are buying new cars, not used ones as the internal combustion collector likely is, so they are creating new demand.
Limo fleet operator with internal combustion limos
This owner has drivers for his fleet. They average 16 hours operating a day with scheduling and maintenance, and often idle while waiting. They get lousy gas mileage while moving as well. Let’s say that they manage 8 miles per gallon on average and the limos average 200,000 miles per year each (around 40 miles per hour average over those 16 hours day in and day out).
Those limos are each producing about 625,000 tons of CO2 or about 310 tons. The fleet is driving about 3 million miles per year. That’s about 9.4 million lbs of CO2, about 4,700 tons. That’s worth about $73,000 of offsets from Native Energy.
But in this case these cars are being driven into the ground over 2–3 years then they are junked. The carbon embodied in their frames etc is partially recovered by recycling, but not fully. There are about 17 tons of CO2 in the average sedan before it’s driven. Limos are much bigger and heavier, so lets call it 35 tons. Let’s assume 50% recycling / reuse of steel and the like. That’s back down to 17 tons per car per year. And let’s assume the cars have a 33% annual replacement rate, so five new cars a year. So that’s another 85 tons of CO2 to offset, worth another few hundred, but kind of a rounding error on the heavy usage.
Electric taxi fleet owner
Did you know that Amsterdam’s Schiphol International Airport has the largest fleet of Tesla taxis in the world? 70% of trips from the airport were by Teslas.
And it’s a busy airport.
Netherlands is behind other northern European states in terms of cleaning up its electrical generation. It’s running about 550 grams of CO2 per KWH (pesky SI units). Converting that, it’s about 1.2 lbs of CO2 per KWH. Teslas run about 30 KWH per 100 miles (160 KM), and idling doesn’t count for electrics. Assuming a similar mileage as the limo fleet, about 200,000 per year or 3 million for 15 of them, then that’s about 900,000 KWH of electricity required. That’s just about 1 million tons of CO2, or about a sixth of the gas limo fleet for the same miles traveled.
The embodied carbon of Teslas is higher because of the battery, but recycling the battery also gets more of the carbon back. That’s going to be a bit of a wash, so it will end up in the same range as the limos, about 85 tons of CO2 there as well.
Think about that. A fleet of 15 full-sized Tesla Model S taxis driven the same as a fleet of gas limousines would emit a sixth of the CO2 over the full lifecycle.
But is $15.50 per ton the right number?
You can buy an offset for $15.50 per ton, but what is the actual social cost of carbon per ton of CO2? If you aren’t offsetting it, what is the downstream impact to the world?
The Obama Administration set it at a politically acceptable and low level of $36. The median of analyses is around $90.
That means not offsetting carbon is costing the world about 6 times more for each of these scenarios. The fleet example is more like a $250,000 problem.
And multiply that by the hundreds of millions of car owners driving around the world.
It’s a big issue.
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