I remember a guy telling me his car was electric, and I said, (just to bust his chops a bit) "You mean coal powered?". He didn't get it at first, but we then laughed about it.
My first business vehicle was an Excursion towing a dump trailer. It averaged 17 MPG between Highway and Town. I modified it to operate on waste vegetable oil. The lowest I ever paid for fuel was $0.00. That's pretty low. I saved a huge amount of money on fuel costs, operating my business and driving with my band to performances, until the Excursion rusted into pieces. I'm still thinking of finding another one from "down south" and re-visiting that first business model.
I like diesel because of it's history, and that Rudolph originally designed the engine around a bio-fuel. I think we can get back to bio-fuels with algae and other options without diesel engine owners having to change out their drive train. Of course, if solar, wind, tidal, and other energies develop further, they may help. I still think it would be great to use bicycles and hand tools when possible, and limit the amount of hauling material off job sites. That's an entirely different conversation involving varied points of views.