Natural Gas or Ultra Low Sulfur Diesel? Which is the best choice for class 8 heavy duty truck fleets?
By: Bob Johnson CEO
The choice of natural gas versus diesel fuel to power class 8 heavy duty trucks in the United States is complicated but natural gas is gaining traction with trucking companies and shippers.
Advantages of Diesel Technology
On the one hand, diesel technology has several inherent advantages. The technology is durable, safe, with higher fuel economy per diesel gallon equivalent DGE) than natural gas. There is also a nationwide diesel fueling infrastructure and diesel powered engines have an extended operating range between refueling.
Natural Gas is domestically produced, has a significantly lower price per DGE, and with fracking technology there is abundant supply which should mean stable pricing as compared to diesel fuel. Natural gas engines are also reported to run cleaner than diesel engines. However, this benefit is shrinking as older diesel engine technology is replaced by ultra low sulfur diesel burning engines.
How Is the Enviroment Impacted?
This environmental impact benefit of natural gas can engender a lot of debate when life cycle environmental impacts of the two fuel technologies are studied and compared. For example, there is growing concern about methane leaks from natural gas wells and the impact on the environment.
The incremental cost of a natural gas powered truck versus a diesel powered truck are currently substantial. A natural gas powered truck can cost from $40,000 to over $75,000 per truck more than a diesel powered truck. The cost difference is heavily impacted by the number of fuel tanks a buyer wants in order to extend the miles range between refueling. The cost difference issue may be addressed through some form of government subsidy.
Industry experts also point out that the cost of maintenance is $0.02 to $0.03 more per mile for natural gas powered engines. Maintenance facilities must also be upgraded to meet National Fire Protection Association (NFPA) regulations.
The natural gas fueling infrastructure is being built out but still has some significant gaps in it.
Fuel Choice Effects Life Span of Engine
The real wild cards in the cost comparisons between the fuel choices are engine life span, resale values, and new diesel technology with 9 plus mpg in testing environments. The current natural gas heavy duty truck engine is 8.9 liters. This Fall a 12.9 liter engine will become standard for heavy duty trucks. This should increase engine life and increase payloads to diesel technology equivalent. Significantly higher diesel mpg technology would cut into the fuel cost advantage of natural gas.
The natural gas technology for heavy duty trucks is new and evolving. The fueling infrastructure will be built out based on demand. Early adopters of this new technology will help the industry and shippers better understand the benefits and limitations of natural gas versus diesel.
Years ago the debate was between changing from gasoline technology to diesel technology for heavy duty trucks. While the conversion may not be as complete as gasoline to diesel, there are and will continue to be applications where natural gas technology is the best choice.