Wind momentum load, Ṗ_of/Ṗ_rad, as a function of the wind velocity for Mrk 509 (Tombesi et al. 2011, 2012; Liu et al. 2015, and this work), and a compilation of local AGN (PDS456: Nardini et al. 2015; Bischetti et al. 2019, Mrk 231: Feruglio et al. 2015, and IRASF11119+3257: Tombesi et al. 2015). The red symbols are UFOs; the green star is the ionised [OIII] wind for Mrk 509; the blue symbols are molecular winds, and the magenta star is the total wind (ionised plus molecular phases) for Mrk 509. The black dashed line indicates the expectation for momentum-conserving wind driven by the AGN in Mrk 509. The red shaded area represents the prediction for an energy-conserving wind with Ṗ_mol/Ṗ_rad = v_UFO/v.