  Practical quantum computing applications to power grids are nonexistent at
the moment. This paper investigates how a fundamental grid problem, namely DC
power flow, can be solved using quantum computing. Power flow is the most
widely used power system analysis technique, either as a stand-alone
application or embedded in other applications; therefore, its fast and accurate
solution is of utmost significance for grid operators. We base our studies on
the Harrow-Hassidim-Lloyd (HHL) quantum algorithm, which has a proven
theoretical speedup over classical algorithms in solving a system of linear
equations. Practical studies on a quantum computer are conducted using the WSCC
9-bus system.
