I have many different power sources.
My AE system is powered by solars; currently one MV array and five LV arrays, for a total of 52 EU/t (I have the output of all IC2 renewables nerfed by 50% in the configs, including the compact solars). As the network grows, this number will increase.
My MJ machines are powered by a bank of six combustion engines, controlled by pipe gates to only run when the intermediate redstone energy cell has room for energy. That's a theoretical 36 MJ/t minus a small bit of loss. However, I've had five of those deactivated for ages. The single remaining engine is more than enough to cover my MJ needs, and even so it's sitting idle often. The combustion engines run on fossil fuel; since the start of this map, I've consumed about 200 out of the ~1000 buckets of oil that my local oil well yielded. MJ machines I have: the six TE machines, three carpenters (water/seed oil/honey), Forestry centrifuge and squeezer, assembly table with six lasers. Also a quarry, but not currently set up.
My EU machines draw power from an array of four MFSUs. Energy input comes from either a pair of nuclear reactors at 672 EU/t (2x 280 at +20% output boost config), or four GregTech thermal generators at 96 EU/t. Both are activated manually when needed, depending on how much juice I need and how much lava I have stored. Nether pumping is disabled, I grab lava from overworld lakes I encounter while mining only. EU machines I have: three industrial grinders, one industrial blast furnace, one matter fabricator, two industrial centrifuges, two assembly machines, one wiremill, one automatic one canning machine, one chemical reactor, one macerator, one compressor, one extractor, one implosion compressor. Three more nuclear reactors stand ready for future expansion.
I also have a single 1 LP boiler running off creasote oil that used to power a Forestry tree farm. But now that I have multiple thousands of all 4 vanilla wood log types, that is shut down too.
