Pretty good! Though it feels a bit monotone from start to finish...
Just a personal opinion but maybe adding a kind of goal for energy production might be good. Right now it's just a "max X multiplier" that can be achieved by linking the power plants pretty much in any order. A goal (or an optional challenge, more likely) like a "$ 3.00 M/min" would challenge the player to link things more carefully (especially after unlocking new areas) or serve as a comparison for how well they're doing. I made Y million / minute, but I don't know if I'm a genius or just average, or maybe even dumb. That kinda thing.