What is the point in promoting it? From the whole 'environmental, sustainability' perspective it's pointless; I see no reason to promote a biofuel which cannot extrapolate into a significant reduction in fossil fuel usage on the large scale.

You may as well keep this one in house, ie for those who are currently using it. It only takes two or three people per fish 'n chip shop radius to result in this little 'hobby' being no more cost effective than gasoline.