In the early 1970s, American gasoline consumption was increasing rapidly while domestic oil production was declining. As a result, Americans were becoming more and more dependent on foreign supplies of oil. Then the unthinkable hit. Due to our involvement in the 1973 Yom Kipper conflict, an oil embargo was imposed on the United States by the members of OPEC. Within days, there were country-wide fuel shortages in the US and sky-rocketing prices.
Most of the nation’s automobile makers considered this oil embargo to be a wakeup call. Without petroleum, the cars and trucks they make would be pretty useless. Perhaps now was the time to start to look at alternatives.
Petroleum products, such as gasoline and diesel fuel, are not the only way to power cars and trucks. A solid alternative, certainly these days, is electricity. Funny thing is that it’s actually an old-time power source because many of the earliest automobiles were electrically powered. The limiting factor for most of the old electric cars, Suburban of Ann Arbor, a local Chrysler, Dodge, Jeep, Ram dealer in Ann Arbor, MI, explained to us was the amount of electricity that the on-board batteries could hold. This equates to the range of the vehicle which in the old days could be just 5-10 miles. Today, of course, range is not a significant issue because batteries are so much better.
Today we routinely hear of other alternative transportation fuels. Among the most common are fuels such as Hydrogen, Methanol, Propane, and Natural Gas. Just about everything except coal. Funny thing is, coal has been explored as a viable transportation fuel and few people know about it.
Three decades ago, General Motors developed a prototype engine that was powered by coal. The selection of the fuel source was based on sound principles: the United States has greater coal reserves than any other country, nearly 500 billion tons according to the Federal Energy Department. And coal beats other fossil fuels by being the least expensive energy source when measured in B.T.U.s per dollar. Since there was concern in the 1970s that the United States was becoming overly dependent on petroleum, coal-powered cars seemed like a good idea.
The engine that GM designed was not powered on the chucks of coal that you see in coal fired furnaces. It was a finely ground coal dust that was fed to a specially designed turbine engine. Compared with a piston engine that normally operates at 800-4,000 rpm, the G.M. coal turbines idled at 35,000 rpm, and ran at 65,000 rpm. For that reason, a beefy gear reduction system was added to the turbine engine. The transmission used was a conventional G.M. three-speed automatic transmission. While the engine and fuel were experimental, the engineers tried to use as many production parts as possible on the car to keep costs down. There was a very real possibility that this vehicle could go into production.
The final prototype engine was installed under the hood of a 1978 Cadillac Eldorado. The coal was stored under the hood so it was near the engine. The delivery system, as described by engineer John Schult, was something of a Rube Goldberg contraption with an tiny conveyor belt that fed the coal dust to the engine. Mr. Schult also recalled the unusual starting procedure and sound of the Eldorado. “The engine was started with diesel fuel, and then once running it switched over automatically to the coal,” he said. “The sound was unique, that characteristic whine of a jet engine. And then there was the constant high-frequency buzz of the agitator that kept the coal dust ready for delivery, overlaid with the noise of the compressed air system that blew the coal from the conveyor into the gasifier. It didn’t sound anything like a regular car engine.”
General Motors built only one coal-fired passenger car, Mr. Schult said. The experiment proved it could be done but, he added, was “too exotic to be practical at that time.” Today a coal-powered car is but a footnote in automotive history.