Steve Hansen also points to the Exxon Mobil report that says, "Diesel will surpass gasoline as the number one transportation fuel worldwide by 2020 and continue to increase its share through 2040, according to ExxonMobil's recently published Outlook For Energy: A View To 2040. The relative shift away from motor gasoline to diesel is driven by improving light-duty vehicle fuel economy and the growth in commercial transportation activity. Diesel demand accounts for 70% of the growth in demand for all transportation fuels through the forecast period to 2040. Although natural gas will play a greater role as a transportation fuel by 2040, it remains only a small share of the global transportation fuel mix, at 4% by 2040, up from today's 1%.”
He also points to the "The World Energy Outlook” finds that diesel fuel will remain the "dominant” growth fuel between now and 2035, according to the International Energy Agency (IEA), the author of a November 2012 report. Even with assumed growth in natural gas and biofuel substitutes, diesel fuel continues to be the dominant fuel for well into the future, according to the IEA report. Globally, the report suggests the possibility of only a two percent share of natural gas in the heavy duty transport market by 2035.
The National Petroleum Council in its 2012 report "Advancing Technology for America's Transportation Future” for the U.S. Department of Energy stated: "Diesel engines will remain the power-train of choice for HD vehicles for decades to come because of their power and efficiency. There are, however, opportunities to improve the technology. Significant fuel economy improvements in diesel powered trucks are possible. Indeed, the fuel economy (mpg) for new Class 7 & 8 HD vehicles, which consume more than 70% of the fuel in the trucking fleet, could be doubled.”