Emissions from My Trip
I live 720 miles from my kids. I took the time to quantify how my travel choices will impact my emissions (and my time and budget) for this trip that Celeste & I plan to take regularly over the upcoming years. My kids live in Chicago, IL and Grand Rapids, MI which are about the same distance from our home in Asheville, NC. I use Grand Rapids as my destination for my calculations. Here’s the bottom line for two people traveling from Asheville to Grand Rapids and back again:
Air travel is the most convenient, and the most expensive, and also has over twice the radiative forcing of the other options I have - and fully 5 times the emissions from driving a fuel efficient car or an electric vehicle. A train, if available, would be the lowest emissions but there is no train route from Asheville to Grand Rapids or Chicago. Driving options are differentiated by the fuel efficiency of the car. It was a surprise that the Prius which gets over 50 miles per gallon is currently almost as low of emissions as the Tesla Model Y, mostly because the trip requires that I recharge the Model Y in Kentucky and Indiana which both have significant electric generation from coal fired plants so Kentucky and Indiana have higher emissions per kWh of electricity.
Here’s how these options break down.
Air travel
Like many regional airports, most flights available out of Asheville get me to a destination through a spoke-and-hub system with two flights in each direction. Direct flights lower emissions and are worth a bit extra cash to not only save time but also reduce emissions. But for my trip, the only option is a spoke-and-hub connecting flights.
To calculate my emissions, I used the route from Asheville (AVL) to Atlanta (ATL) and then to Grand Rapids (GRR) flying economy. It’s a similar distance as the alternative routing AVL to Charlotte, NC, to GRR. To get a complete estimate at of the greenhouse gas emissions I used myclimate (https://co2.myclimate.org/en/flight_calculators/new) which calculated that the estimated CO2e emissions including non-CO2 radiative forcing is 1.3 tons CO2e for two round trip passengers. This estimate includes the additional ways that air travel causes our climate to warm beyond the CO2 emissions from burning jet fuel - through the release of water vapor, aerosols and nitrogen oxides at high altitudes in the atmosphere where the airplane travels. The methods to account for these non-CO2 radiative forcings have more variability and so this estimate, while more complete than just calculating the CO2 emissions from the fuel, also has more uncertainty.
I can also estimate just the CO2 emissions from burning the fuels using the ICAO calculator (https://www.icao.int/environmental-protection/Carbonoffset/Pages/default.aspx), the estimated CO2 emissions from the fuel alone is 0.68 tons of CO2 for two round trip passengers.
The cost for these flights is around $1,100 for 2 passengers and our two suitcases if I booked the trip in advance. Once in Grand Rapids, I’d either need UBERs or I’d need a rental car that would add more expense not factored in here.
The trip would take between 6 ½ to 9 hours depending on the flights I choose. This includes a half hour drive to the airport on both ends of the trip, getting to the airport an hour before my flight, and it takes me a half hour to deplane, claim my bags and get out of the airport.
Direct flights are more fuel efficient. If I flew from Asheville to Chicago’s O’Hare International Airport, the total emissions calculated by myclimate drop from 1.3 tons down to 0.78 tons. Still higher emissions than driving, but much lower than a spoke-and-hup travel. And the travel time drops significantly but I am also dropped at O’Hare airport. Fantastic if I want to use Chicago’s rail and stay in Chicago, not as good if I want to rent a car so I can also drive over to Michigan. Furthermore, flying into O’Hare drops the price by $400 for 2 passengers.
Automobile
I estimated four options for travel by car (two matching the cars we own): A Tesla Model Y electric car, a Toyota Prius hybrid that averages 52 mpg, a standard compact car that gets 36 mpg highway, and finally an SUV that gets 22 mpg highway.
The round trip from Asheville to Grand Rapids is all freeway and is 720 miles (1,440 miles round trip). With an assumed cost of gasoline at $4 per gallon, the math for the gas powered cars is relatively easy for emissions and cost from the fuel for the round-trip.
The Tesla Model Y uses about 28 kWh/100mi. This is how the Europeans report fuel efficiency, with the energy used on top over a standardized distance or L/100km for gasoline - it is a bit more intuitive once you are used to the “lower” number being a more fuel efficient vehicle. For an electric vehicle, it’s important to know that we will drive through Kentucky and Indiana where the electric power has more coal generation. Here are the typical emissions for a megawatt-hour of electricity in the five states I’ll drive through where I’ll stop at a Supercharger Station (https://www.statista.com/statistics/1133295/electric-sector-carbon-dioxide-emission-rate-by-state-united-states/)
North Carolina 0.30 tons CO2/MWh
Tennessee 0.30 tons CO2/MWh
Kentucky 0.79 tons CO2/MWh
Indiana 0.73 tons CO2/MWh
Michigan 0.46 tons CO2/MWh
Assuming a mid-range of 0.50 tons CO2 per MWh the emissions from the Tesla Model Y would be 0.20 tons CO2. For an upper estimate with 0.70 tons CO2 per MWh the emissions would be 0.28 tons CO2, and for a lower estimate with 0.30 tons CO2 per MWh emissions would be 0.12 tons CO2.
A typical cost of the electricity at a Tesla Supercharging Station is $0.28/kWh, so the cost of the electricity (fuel) would be $113 (if I returned home with the same amount of charge in the battery as when I left).
The trip by car is a very long day of driving - 11 hours on the road, with an additional 3 hours of charging. Using the Tesla does require a bit longer breaks, but I can plan them for meals when I get out of the car and stretch my legs. I have not used the Tesla Supercharger network on this stretch of freeway, but they are typically co-located with a restaurant and a clean bathroom. Tesla has a tool to help plan your route which indicates I’d need to stop 4 times for a total of 2 ½ hours of charging - but I always stop more than four times on this trip to stretch my legs.
Train
There is no train service from Asheville to Grand Rapids. So there is really no comparison to be made here. But for those people fortunate enough to live near a train line, let’s explore a comparable length trip from Greenville, SC (GRV) to New York, NW (NYP); a 723 mile car trip that would take 12 ½ hours each way by car. This would be a 16 hour train ride that I’ll add another hour to for access and deboarding - a 17 hour trip. And to travel in both directions for two people would cost $488 and emit 0.12 tons of CO2 (https://ecotree.green/en/calculate-train-co2). Similar to air travel, once at my destination, I’d either need UBERs or a rental car that would add more expense not factored in here. And, as I stated in the beginning, in America, this is simply not currently an option - the train does not travel to Asheville. And the train stops near Asheville have connections aligned with going northeast toward DC or New York; or southwest toward Atlanta and New Orleans - no routes cross the Appalachian Mountains to efficiently travel from the Southeast to the Midwest.
Hotel Stay
The options where I drive for this trip also includes a hotel stay in both directions, as I typically break the drive up into 2 days. A double check on the emissions, indicates that this does not materially change the conclusions from the emissions listed above. The average emissions from a single hotel room near Cincinnati, OH is 0.02 tons CO2e per room-night (https://www.hotelfootprints.org/), or 0.04 tons CO2e for the two hotel rooms, one driving north and one driving south. Adding these emissions into the calculations for travel by automobile listed above doesn’t change the comparison of the emissions for each type of travel.
Relation to my other trips
This exercise took some time to complete. It wasn’t complicated, but it also wasn’t a quick check using some app on my phone. The exact emission ranking will not match the other trips plan, or you might take, but I believe the relative differences that jump off the page are helpful in evaluating the options we have and how we choose to travel.
Probably the largest reduction I see is trying to eliminate the trips I take on an airplane. This can be significantly impacted by what destinations I choose to travel to. If my family were in England or across the country in Boise ID, driving might not be an option. But for my vacation travel I do have a choice on the destination - so maybe I’ll pick a vacation in the beautiful southeastern United States instead of the trip to Boise ID or England - that change in destination would have a very material impact on my emissions. And, I know there are many beautiful and interesting destinations within an 8 hour drive from my house.