1.5.2:
Various arrays of IC2 reactors + solar arrays + water mills
Efficient, semi-renewable, not cheap, powerful+
GT Diesel generators + geothermal generators
Efficient+ non-renewable, cheap, powerful
1.7.10:
Various arrays of 1 chamber IC2 reactors + solar panels + water mills + kinetic wind generator
Efficient++, semi-renewable, semi cheap, powerful+
Now using this:
6 core fission reactor from reactorcraft
Producing 5K+ EU/t it's efficient++, semi-renewable (if you condense the steam like I do) not cheap+,but powerful+++
I can grab screenshots of my 6 core reactor after I finish rewiring my base and complete the new 6core design. (I made it in creative and got over 5K EU/t)