I've been tinkering with buildcraft, industrial craft and the crossover mod for sometime now, and i built something which works rather well for my needs:
x4 oil refineries which transfer the fuel into a series of tanks, which then transfer the fuel into x4 petrochemical generators, and then into x3 MFSU'S.
Total output: 20.4 million EU
Energy input: 1.2 million eu over two solar array grids (one to power the industrial engines, the other to power the small electric engine used to power the buildcraft pump.