Recent developments (blackouts, green energy, shut off of nuclearpower plants in Germany) have drawn focus towards the efficientcalculation of flows in AC power grids, which are difficult to solvesystems of nonlinear equations. The common linearization approachleads to the well known and often used DC formulation, which has somemajor drawbacks. To overcome these drawbacks we revisit an alternativelinearization of the AC power flow. Work on this model has already bedone in the 1990s but was intractable at that time. In view of recentdevelopments in the field of integer programming, we show that thismodel is now more computationally tractable.