Howdy,

The only efficient fuel for moving heavy loads is diesel fuel. Diesel fuel constituents are heavier at the molecular scale. One way to look at it is thus;
the flash point moderator for gasoline is C8H18 Octane, whereas the flash point moderator for diesel is C16H34, decahexane. Both moderators are in the paraffinic class of alkanes. Simple carbon chains with hydrogen atoms bonded. This is why diesel is used in compression ignition engines. Most cars have gasoline engines, and are SI, or spark ignition. Modern diesel engines have compression ratios that are 16:1 up to 18:1. Gasoline engines have CR's about 8:1.

Now think about this. Why are all large tractor-semi trailer combinations powered by diesel? Because the diesel engines produce more torque at output. Its a btu trade off. A car running on gasoline or ethanol can produce higher rpm with less torque, and go faster, but it (gasoline) cannot pull heavy weight.
If you have driven across I-70 from Salina Utah to Denver Colorado, you know why the big trucks need the greater torque. Thus the heavier fuel.

Diesel fuel has many constituents. The paraffins are used to lower flash point, thus setting off exothermic reactions in even heavier molecular structures. It's a combustion ladder. There are iso-paraffins, aromatics (benzene) and other compounds containing sulfur. The aromatics are the heaviest; a 6 carbon ring with hydrogen atoms locked in endothermic quadravalence with the carbon. This is the heaviest constituent, and once the carbon ring is destabilized by compressional heat, it then goes foward into exothermic oxidation. (With atmospheric air)

I don't see an end to big trucks using diesel as main line fuel as yet. I have not seen any electrical applications that can handle that kind of weight (80,000 pounds) Heat problems due to mass amperage runs. Believe me, I have worked on this problem. Sorry Chris, but I aced all my chem classes. My nemisis;
calculus.

Glen