Within IC2, you are suppose to move up from a coal generator,
to a geothermal generator,
to a liquid fuel generator (you can create bio-fuel within IC2 )
to a nuclear generator,
to a steam based nuclear set-up,
to a steam based nuclear set-up that uses mox fuel rods instead of uranium rods.
Also keep in mind that the fuel burning generators burn an entire fuel item, even if only a fraction of that is used. So if you have a machine that uses a small amount of EU a tick for a very long time, you will burn though stacks of coal, where most of it is wasted. (especially if you have multiple generators in parallel)
To prevent this, try make a contraption that only inputs fuel if a nearby battery is below a certain amount.
You can also use solar panels/ wind mills/ water mills, to keep things going that use a small amount of energy continuously.
I think the real progression is: Coal > Solar > Nuclear
Coal gives you the entry level power you need to build your first machines.
With those machines you can make enough solar cells to generate ~32EU/t.
With 32 EU/t you can run the 3 stage ore processing pipeline and refine uranium and make uranium rods, and thus a simple nuke.
That gives you a stable starting 60EU/t in a reactor that you can upgrade to reach 420 EU/t.
From there you can build the 5x5x5 reactor and harvest its power either using thermoelectric generators, or Steam, But steam is frankly complicated as there is no design that can actually produce the correct amount of heat to operate the steam system efficiently. The 7 rod 420EU/t layout instead generates 1344 HU/s as a fluid reactor: Thermoelectric generators yield 1EU/t for every 2HU/s - so that would give 672EU/t - the Superheated steam>Steam pipeline gives up to 1.5 EU/t for each 2 HU/t: so you could reach a theoretical 1008EU/t with that design as a Fluid reactor.
Or you can stick with the 3x3x3 reactor and use that Plutonium you are getting to run a MOX reactor that, properly heated, provides an up to almost 5x power multiplier to your reactors base output - so a 5 Quad MOX reactor can reach a theoretical 1500 EU/t output - with a far simpler build than Fluid>Steam requires.
MOX reactors are the real way forwards, as the plutonium you collect from those you craft into Plutonium bricks that you can put into radioisotope generators that will then provide (Each) a completely passive unlimited supply of 32EU/t.
You can't really mix Fluid and MOX as the only way to build up heat in a Fluid reactor is to produce more heat than you are draining which is a recipe for disaster. There are people on the IC2 forums who build reactors that... achieve great efficiency with the complication that heat buildup occurs - and they manage this with the blast proof blocks, red stone timers to cycle the reactor on and off, and, presumably, the occasional rebuild.
Suffice it to say: stable designs are stable - if you implement a stable reactor design there is no need to build it away from your base, or to encase it in blast proof blocks.
