Even offsetting a twelfth of our annual diesel fuel consumption would be a major accomplishment towards reducing our dependence on foreign oil.
But perhaps this sort of thing will proceed grassroots, as it has been - the last time my brother bought diesel fuel was 2 gallons on the way home to Berkeley from a trip to Los Angeles, after burning 40-odd gallons of used fryer oil that he took off the hands of a San Francisco restaurant during the trip.
That comes under the heading of "every little bit helps," but it is not transformative. Private consumption of diesel is negligible in terms of total consumption. Also, diesel alternatives cannot be used everywhere, and for some uses require considerable reprocessing.
We already run a VERY significant part of our commercial transportation on hybrid technology - every locomotive is primarily a set of electric motors to drive the wheels. Most of them also contain a large, diesel-electric generator to drive those motors, but in many places they run off of external power, supplied by a third rail or a trolley.
By the way, this is why I have to laugh when I hear about the difficulty of scaling up the small hybrid cars that are available today.
But suppose most of our cars were like this - electric powered, but with on-board generation capability to free us from the tether of external power. And now suppose that for intercity trips, or even for in-town driving by some means, you could tap into an electric grid for motive power. This would actually require little more power than our current grid can provide, and would provide a great deal of relief from dependence on oil. This would be truly transformative, and send the oil sheiks back into their tents in the desert, where they could use their oil to keep warm because we don't need to buy it from them any more.
Today, nearly 3/4 of all crude oil becomes transportation fuel, and over 95% of transportation fuel comes from oil. The lead article addresses some ways to change these numbers, but it will not happen overnight.