I found that ammonia was used as a fuel for some modified internal combustion (IC) engines, it also was used in conjunction with gasoline but the 2 were fed separately. If ammonia is miscible with gasoline, then burning such a mixture may be more environmental friendly. (Something tells me that this is not a case, since I can't find any references to that). Ammonia is a clean burning fuel with 15.3 MJ/l (compared to gasoline 36.2MJ/l, ethanol 23.4 MJ/l, liquid H2 9.9MJ/l) that can be produced from methane and holds promise for fuel cells, particularly Direct Ammonia PCC. Ammonia could also be produced from renewable sources only, since all input ingredients are: air + water + energy. It is easier to store and handle then hydrogen.