Although LP has been more frequently tried, CNG experiments have been fairly constant for at least 40 or more years. Nearly all testing considered "successful" (often based on hallucination rather than observation) has been in "local fleets" such as taxis where wide speed ranges - and associated need for variable acceleration - were minimized. There have been multiple tests in (local) passenger/transit buses that have claimed some benefits, but tests in heavy haulers have been disasters, as a rule.
Although fairly popular with some truckers (for patriotic reasons?) the agri-fuel also as a rule reduces fuel mileage compared to petro-diesel by amounts estimated at 5 to 15%, according to the truckers who use it enough to know so that even though burning a pound of the ethanol spiked stuff gives slightly less polution than a pound of ordinary diesel, you have to burn enough more pounds of the home-brew stuff that the net difference "per ton-mile" in the better of the current engines at least is pretty marginal.
Continued investigation of alternatives to the current fuels is worthwhile, as long it offers the likelihood of improving something, but many of the infinitely repeated announcements of "new applications" are just rehashing what's already failed to produce any significant results.
Someone will report the "new use" of the "ultra-flywheel" system again within six months or a year, and it will be tried again, quite probably with the same results as in 1954.