  Quantum computing has the potential to solve many computational problems
exponentially faster than classical computers. The high shares of renewables
and the wide deployment of converter-interfaced resources require new tools
that shall drastically accelerate power system computations, including
optimization and security assessment, which can benefit from quantum computing.
To the best of our knowledge, this is the first paper that goes beyond quantum
computing simulations and performs an experimental application of Quantum
Computing for power systems on a real quantum computer. We use five different
quantum computers, apply the HHL quantum algorithm, and examine the impact of
current noisy quantum hardware on the accuracy and speed of an AC power flow
algorithm. We perform the same studies on a 3-bus and a 5-bus system with real
quantum computers to identify challenges and open research questions related
with the scalability of these algorithms.
