The legacy of experimentation with alternative fuels to gasoline is nothing new. It started back in the earliest days of the car in the late 19th century. Alternatives to piston engines are also not new, although none but the Wankel rotary
have had any notable commercial success. Starting back in the 1950s, there was a lot of interest in trying to run cars on turbine engines. Turbines had some inherent advantages,including high power density and, most importantly, the ability to run on virtually anything combustible. In the wake of the first Middle East oil embargo, the search for gas alternatives heated up again, and the engineers at General Motors came up with a novel idea: a coal-powered Caddy. The US had plenty of coal, after all, and GM had a turbine engine. The General's engineers therefore built a Cadillac Eldorado with a turbine engine that ran on powdered coal. As a proof of concept, it worked. The car ran fine. As a practical alternative? Not so much. The coal powder was messy and difficult to handle and the engines produced high NOx emissions. Then there was that pesky problem of a re-fueling infrastructure. Where have we heard that one before?
[Source: New York Times