I admit ignorance of the mechanics of the subject, but how easy, hard, cheap, expensive is it to convert an existing gasoline engine to use natgas, butane, propane? It’s really the only viable alternative to gasoline and diesel that I see in the foreseeable future, but that’s JMO.
Found this in the article. Sounds like an outrageous cost to me. I gotta believe some good ol' boy shade tree mechanic has found a way to covert a vehicle at much less cost.