Board Thread:Questions and Answers/@comment-5878752-20121216183318/@comment-98.225.22.50-20121216210134

In single player, only one dimension is allowed to be loaded, despite anchors, probably to save RAM. This means that you can either go to the nether to fill it up and come back to use it, or you can move to the nether. Unfortunately, there is no good way to exploit nether lava lakes from the overworld. IMHO, with nether ores and canning machines for rotten flesh, living in the nether is perfectly viable, and I have done it myself. Good Luck.