Start a skirmish game with a limited resource/unit start (lowest of each), you start with 2500 credits. No other settings seem to matter (number of players, difficulty, etc). The enemy AI will build two power plants for 600 credits, starts building their refinery, and is not be able to complete it. They never start their economy.

This explains it:

For the second run, notice @6:05 I attack a power plant, but not enough to be a threat to sell before destruction. Then @6:56 I attack a different power plant with two units, with enough threat for the AI to sell both plants, immediately finish the refinery, and start his economy to break the bug and continue the AI build path.