Suspect the 6 year time frame is due to restricted operating window due to weather and enviro regs, time to build infrastructure (pipelines to bring oil from well to Trans Alaska Pipeline, electric power to pumps etc.), and permitting turnaround times.
During the warmer months that ground turns into mush meaning no equipment moving, only when frozen solid can trucks and equipment roll. There’s a convoy of vehicles going to and from rigs once they start drilling.
Power is less of a concern, most of that comes from the well itself. Motors running off of casing gas and gas lift wells are self supporting.