Extra utilities survivalist generator is my 1st RF generator. It only makes 5 RF/t, but a single piece of coal lasts for 15 minutes. I used to use a leadstone energy cell to start for power storage, but with the new tiered Ender IO capacitor banks, I've switched to them since they are expandable. That is good to power early ore processing. In my last world, I used them until I could get a small Big Reactor going. In my current infinity world, I spawned next to a desert with lots of oil, so decided to use a few compression dynamos with the efficiency upgrades. 1 bucket of fuel gets 1.5 million RF with no augments. Once you get the 3rd upgrade, one bucket gets almost 2.8 million RF.