GreenIRR CEO Explains How Fuel Efficiency, Carbon Emissions Are the Same Number In Trucking

Celine King, CEO of Brown and White Ventures portfolio company GreenIRR, explains how, in trucking, a carrier’s fuel bill and its carbon emissions aren’t two metrics that happen to move together. They’re the same measurement in two units.

Burning a gallon of diesel produces a fixed quantity of CO2, about 22.4 pounds by the EPA’s factor, and that ratio never changes, because it’s chemistry rather than policy.

Diesel is roughly 87% carbon, combustion turns that carbon into CO2, and the molecular weights do the rest. So every gallon a fleet saves shows up twice: once as dollars, once as carbon.

That matters because fuel is one of the two largest costs a carrier carries. In ATRI’s latest data, fuel ran 48 cents per mile in 2024, about 21% of the $2.26 cost of operating a truck, and closer to a quarter in higher-price years. Back the numbers out and one gallon is worth roughly $3 and about 0.01 metric tons of CO2e.

Trim 1,000 gallons off a lane and you save on the order of $3,000 and avoid about 10 metric tons of CO2e, from the same action. Efficiency and decarbonization aren’t competing for budget. They’re one project with two reporting lines.

The room to move is real. The average Class 8 truck gets about 6.3 mpg while newer aero-spec trucks have demonstrated 9-plus mpg in on-road testing. A tractor running 100,000 miles a year at 6 mpg versus 7.5 burns about 3,400 more gallons, worth roughly $10,000 and about 34 metric tons of CO2e per truck.

The levers, aerodynamics, tires, idle reduction, routing, and fleet age, are ordinary operational decisions, and each gallon they save lands on both ledgers in the same 22.4-pound proportion.

The strategic upshot for shippers: you don’t have to choose between a cheaper carrier and a cleaner one.

On diesel freight, the efficient carrier is both, and fuel efficiency is the shared signal. It’s also why the GHG Protocol’s fuel-based method beats distance-based estimates, since the same fuel data that runs a carrier’s cost model produces a defensible Scope 3 number for the shipper.

Pay for verified gallons per ton-mile and you’re buying lower cost and lower emissions in one transaction. Get the operational number right and the carbon number is already there, in the same units.

Efficiency is the lever. Carbon is what the lever also moves.