  The multi-rotor (MR) wind turbine concept can be used to upscale wind
turbines without increasing the rotor diameter, which can be beneficial for
transport, manufacture and design of wind turbines blades. The rotor
interaction of a MR wind turbine leads to a faster wake recovery compared to an
equivalent single-rotor (SR) wind turbine wake. In this article, the benefit of
the faster wake recovery of MR wind turbines is quantified using
Reynolds-averaged Navier-Stokes simulations of a 4x4 rectangular MR wind farm,
for three different inter wind turbine spacings. The simulations predict an
increase of 0.3-1.7% in annual energy production for the MR wind farm with
respect to an equivalent SR wind farm, where the highest gain is obtained for
the tightest inter wind turbine spacing. The gain in AEP is mainly caused by
the aligned wind directions for the first downstream wind turbine in a wind
turbine row of the MR wind farm, which is verified by an additional large-eddy
simulation.
