Someone above made reference to a statement that diesel would never be higher than gas.
It reminds me that several years ago, I predicted that natural gas (for residential heat) was going to go up faster than electricity, so people should opt for a heat pump when feasible rather than gas heat. Then we elected a guy who doesn't like coal five years ago, which has tended to push up electric rates thanks to the EPA's tightening emission rules, and the 'fracking' revolution has led to a huge drop in gas prices. A few years ago, who among us had heard of fracking?
It keeps one humble.
(BTW, a heat pump still runs cheaper than gas heat at reasonable outside temps, say down to 40 degrees. If anyone cares, I'd recommend a hybrid system today: gas heat below about 40, heat pump above. All the major HVAC companies have hybrid/dual fuel systems available.)