Given all the concerns we have today over vehicle emissions, it’s almost impossible to imagine that just a few decades ago, engineers at GM came up with a car that could run on coal — specifically, superfine coal dust. The dust was blown into a turbine engine like you would find on a jet and burned as fuel. The turbine engine has a lot of desirable traits. It’s relatively compact and it can burn just about anything as fuel. It’s an incredibly smooth means of propulsion because the motion of the motor is all rotational, not reciprocating. It also sounds like a jet taxiing. Unfortunately, the downside is that the exhaust produced by the turbine is hot enough to set just about anything on fire. It’s also not exceptionally efficient when it’s idling at 22,000 revolutions per minute. In fact, turbine engines are inherently dirty, which is why the idea never really took off.
