What are the problems with steam power, and why isn't it used to power automobiles? Footnote -- this isn't intended as some sort of whacko alternative energy thread. I Really only want to know the real fundamental problems behind the steam engine, and why the average joe's car isn't powered by one. If anyone suggests a couple of ideas (example -- fuel is needed to heat the boiler, then why not use an electric element similar to stove). Feel free to call this stuff practical/impractical, and explain why.