Regarding nuclear power: I've read the IC2 forums, I have the planner tool and have copied the "best" configs into a CSP world. Out of 5 reactor designs I've tried to emulate in creative only one didn't leave a large crater: the 0 chamber. Tried MOX: explosion. Tried 3 chamber reactor: explosion. Tried 6 chamber reactor: explosion. Tried fluid reactor: even bigger explosion. 0 chamber reactors are great and all, but they don't really produce very much EU/t. I'm pretty sure my problem is that when I attempt to copy the config from the reactor planning tool into my game client I'm just swapping a heat exchanger here with a coolant cell there. But really, that's all it takes to hose it up. It's sad really because I have a gold chest full of thorium dust from processing uranium 238 into Mutagen
But now that I have both plutonium and naquadah bees I'm turning all the plutonium into RTG pellets that I'm going to turn into an array of RTG generators facing into MFSUs to provide backup power for my AE2 network. And the naquadah is coming in slow even with 2 alvearies with perfect trait bees since the centrifuge recipes are so awful. But once I get a decent stock of enriched naquadah bolts I'll build a Mark1 reactor for this and point it into a 16 slot EV battery buffer full of lapotron orbs. This will power, um, something I guess
Regarding steam power: My 48 coke ovens are still going strong, but they'll get disassembled as soon as I get around to setting up a chilli pepper farm and redoing my charcoal production with thaumcraft. This will mean converting my 2 36LP boilers from liquid to solid fuel. But that's OK as the only thing I use steam for anymore is to power some old LV machines that are tucked away in a back corner of my base. These are used for automated processes where I don't care about speed: like compressing cobblestone, generating obsidian, making rubber bars from rubber trees, ore washing, and some centrifuging. It'll be good to take down my last RC iron tank used for creosote and replace it with...nothing. I'll keep my max size RC steel tank around for looks I guess even if a bedrockium drum would be better now that I can make the top tier eIO fluid pipes.
Regarding liquid power: IC2 biomass into GT distillation tower is powering most of my base right now from 1 carrot farm. I fully expect this to get nerfed somehow, some day. But for now I'm working on filling my 3rd bedrockium drum with biogas and I'm even considering building a 2nd distillation tower sharing the same multiblock structure with the one I have now because I'm producing biomass with 1 fluid/solid canner faster than 1 distillation tower can handle. I'm guessing by the time IC2 biomass becomes less viable that GT oil processing will be a thing so I can switch pretty seamlessly to that.
Don't forget about magic power!: I've also got draconic bees, every type of TC shard producing bee, and well basically every type of bee except for those in the attuned branch (made a 2nd ender quarry last night that is going to just mine magic forests for these). I just need to make some blank schematics for strontio aspect and then I can churn out a pile of HV magical energy absorbers. Whether I plunk a dragon egg on top or just feed more hungry nodes, this will be an interesting power source