Probably the most annoying problem in the removal of IC2 is the lack in TE of some sort of serious mid-late game energy sources as in tekkit lite are nuclear reactors and solar arrays and mostly the total lack of fully renewable power like windmills , watermills solars or the most used late game power source the HV solar array . Sure you can go on with TE even without these power source but to reach a comparable energy production you will have to build huge power plants that use non renewable resources like lava or oil and that's not good . There are quiet a few ways to produce energy with renewable resources tough but still you have to get loads and loads of these machines to reach a comparable energy uotput . Anyway the new Tekkit is pretty awesome , and the "unified" energy system ( BC's MJs ) simplifies a lot the way Tekkit works and that's a good thing . For some serious late game power source , well , lets hope that the TE developer or some unkown guy who wants to make a addon for BC gives us a mod with a lot of new machines that work on renewable resources .