In Pinehurst, in the construction site (very above average sized), climb the stairs nearby (next-door to the Army Surplus store) all the way up to the roof, parkour over the trash and A/C unit onto the next higher roof level and drop down onto third level of the construction site. Put 1 motor oil into the generator to get it running, follow the cable down to the break and repair with 1 cable reel, repeat the steps to get back to the third floor, and insert your concrete bags until the power dies (should be able to get a few concrete slabs each time). Repeat all steps for more, after waiting some time for cooldowns (rather short time period).