I would recommend mekanism, they play well together and you'll need the pipes and cables from mekanism. Plus mekanism gases work with nuclearcraft! As far as something to use all the power for, you could use immersive engineering for resource collection, those excavators use a hell of a lot of RF. Wouldnt be a bad idea to setup a ton of them and power them off nuclearcraft reactors. More on reddit.com

There are various additions and changes in the latest version of NCO , but the ones I'm most excited about are the new custom components and script addon systems. First, there are now one-line CraftTweaker methods for actually adding new custom components to the mod, e.g. heat sinks, coolant heaters, dynamo coils, rotor blades, etc. by hooking into ContentTweaker’s resource loader. Placement rules, stats etc. are all dealt with via a parsing system which (Java) addons can append with more options. Second, NC now has a modular ‘script addon’ loader, where multiple ‘addons’, each consisting of CT scripts adding new components, new assets for those components, and their required localisation, are put into a particular directory, squashed together before NC loads and so all work together (in particular, the lang files are joined together into one .lang and the assets and scripts are copied into the correct locations). There are already four script addons in development: ”Moar Heat Sinks” and "Moar Fuels" by QuantumTraverse, "Nuclearcraft Overhauled: Unrealistic Turbine Overhaul" by Thalzamar, and "NC Extra Ingot Blocks" by FishingPole. Installing a script addon is as simple as extracting the addon zip to the resources/nuclearcraft/addons/ directory (you also need ContentTweaker installed). Writing your own script addon only takes a bit of knowledge about writing CraftTweaker scripts and the basics of resource packs; for more info on how to get started, ask me here or ping me in our Discord server :) [2o.4.0 Changelog] More on reddit.com