But all the junk you want in a DSU(Deep Storage Unit). It holds up to 2 billion items, so no problem with space there.
The main only source of energy in Tekkit now is MJ. You should get started in Thermal Expansion. Basically, make some steam engines(note: not sterling engines, TE's steam engines), and get a pulverizer and a powered furnace. To supply the steam engines with water, get an aqueous accumulator. Place down the AA, and put two buckets of water on the left and right sides of it. This will give you infinite water for your engines. The best part is that you don't even need a wooden waterproof pipe to pump it out, it auto-exports. Beyond that, I'd say to start building up your array of machines, make a powersuit, and get an Applied Energistics network going.