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Calculating Emissions reductions of Class 8 Vehicles if Converted to Electric

Posted by Clean Fuels Intern on Jul. 29, 2023  /  Case Studies  /  Subscribe 0

Written by: Trevor Spinosa; Clean Cities Intern

Medium and Heavy duty trucks play a crucial role in transportation and logistics, but they also contribute to greenhouse gas emissions, air pollution, and climate change. Thirty percent of total emissions in America come from transportation, so reducing vehicle emissions is a major step in optimizing greenhouse gas reduction and even costs. This research paper aims to quantify the total gas emissions generated by semi trucks in Louisiana over the course of one year. Additionally, it examines the potential reduction in total emissions that could be achieved by transitioning from conventional diesel-powered semi trucks to electric versions. 

To estimate the total gas emissions from semi trucks in Louisiana, several key factors need to be considered: 

• the number of semi trucks operating in the state, 
• average annual mileage per truck, 
• average fuel efficiency, 
• the carbon dioxide equivalent (CO2) emissions associated with the combustion of diesel fuel. However, precise data on gas emissions from semi trucks in Louisiana specifically is limited. 

According to the American Trucking Associations (ATA), there were approximately 2.3 million heavy-duty Class 8 trucks registered in the United States in 2021. Based on this estimation, it is reasonable to assume that there are approximately 82,000 semi trucks operating in Louisiana. 

According to AFDC (graph shown below), the average annual mileage for a semi truck in the United States is around 62,000 miles.

The average fuel efficiency of diesel-powered semi trucks ranges from 5 to 7 miles per gallon (mpg). We will assume an average fuel efficiency of 6 mpg. Based on these assumptions, the total annual fuel consumption for semi trucks in Louisiana can be calculated as follows: 

Total Fuel Consumption = (Number of Semi Trucks) x (Average Annual Mileage) / (Average Fuel Efficiency) = 82,000 trucks x 62,000 miles / 6 mpg = 847,333,333 gallons of diesel fuel 

Considering that burning one gallon of diesel fuel emits approximately 22.38 pounds of CO2, the total gas emissions from semi trucks in Louisiana for one year is: 

Total Gas Emissions = (Total Fuel Consumption) x (CO2e Emissions per Gallon) = 847,333,333 gallons x 22.38 pounds CO2e/gallon = 18,963,319,992 pounds of CO2e 

Transitioning from diesel-powered semi trucks to electric versions offers the potential for significant emission reductions. Electric trucks produce zero tailpipe emissions and have lower overall well-to-wheel emissions compared to their diesel counterparts. 

Louisiana's electricity generation mix plays a significant role in determining the emissions associated with electric vehicles. According to the U.S. Energy Information Administration, Louisiana relies primarily on natural gas and nuclear energy for electricity generation, with smaller contributions from coal and renewable sources such as hydroelectric power.

Efficiency of Electric Trucks: The efficiency of electric trucks, measured in miles per kilowatt-hour (kWh), determines how much energy is consumed per unit of distance traveled. Higher efficiency means the truck can travel longer distances on the same amount of energy. 

While the efficiency of electric trucks can vary depending on various factors, a range of 1.5 to 2.5 miles per kWh is commonly observed in current electric truck models. According to the EIA, the emission from producing one kWh is about 0.97 pounds of CO2 using natural gas, which is the leading source in Louisiana. So, if we use the same number of miles driven per year as stated above (62,000), we can estimate the total amount of CO2 emissions by an electric vehicle. 

(Total Miles) / (Miles per kWh) * (CO2e emissions per kWh) = (62,000) / (2.0) * (0.97) = 30,070 pounds of CO2 per Electric Class 8 Vehicle. 

Multiplying that by the total number of trucks estimated in Louisiana used above (82,000), the total number of pounds emitted is 2,465,740,000 lbs of CO2 emitted yearly by Class 8 trucks. 

Conclusions:

This means that 87% of transportation emissions from Class 8 trucks in Louisiana can be reduced through a transition to electric class 8 trucks. This process will take many years but will be worth it financially and environmentally.

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