Emacs is a bunch older than common lisp.
One of its more idiosyncratic design decisions was using dynamic scope, rather than lexical scope. They did add in per-file lexical scope, though.
It also just doesn't implement a lot of common lisp's standard library.
Yeah. Power plants are nowhere near 90% efficient.
It's worth emphasizing, though, that they're still way, way more efficient than car engines are.
Also, regenerative breaking saves a lot of energy. Basically, instead of using the motor to increase the cars speed, you use it as a generator to recharge the battery.