I totally agree with the futility of 1-3 hour buildings, but the EPP has its uses-get it up to ten and you can collect more than a first level nano-every hour. Pretty decent, and really helpful during events. Was a snob to the Electric till WP pointed all this out a while ago.
My strategy is to simply pick up the buildings with the biggest IPH and upgrade them till I can't afford to anymore. I have a 30% discount now so this might be harder for others, but I have 2 level 4 chem plants, level 3 and 4 OR, and will think about the EPP and/or nuke plant.