Presumably your small city is using waste heat, so efficiency isn't as important: the goal is electric and the heat is just waste heat that needs to be dumped anyway. When there isn't the co-generation involved efficiency matters more.
Note too that nobody has defined the actual size. Your idea of a small town could be larger than my idea of a large city. Local factors matter in this definition as well.
Note too that nobody has defined the actual size. Your idea of a small town could be larger than my idea of a large city. Local factors matter in this definition as well.