Biofuel is the way to go. Start with steam engines and make your own manual tree farm using oak saplings. Connect the trees in a row not a big clump because you want to break the whole bunch with an axe but increase the sapling drops. Soon you can make some bio fuel and bio reactors. But to start just farming those trees and cooking logs into charcoal will give plenty of energy. Magmatic engins are going to lag the server and you will need to find new lava sources all the time. Skip the mag's and go for bio fuel and self sustaining farms that will last you forever.