  Using the results of a previous X-ray photo-ionization modelling of
blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs
observed with XMM-Newton, in this letter we estimate the location and
energetics of the associated ultra-fast outflows (UFOs). Due to significant
uncertainties, we are essentially able to place only lower/upper limits. On
average, their location is in the interval ~0.0003-0.03pc (~10^2-10^4 r_s) from
the central black hole, consistent with what is expected for accretion disk
winds/outflows. The mass outflow rates are constrained between ~0.01-1
M_{\odot} yr^{-1}, corresponding to >5-10% of the accretion rates. The average
lower-upper limits on the mechanical power are log\dot{E}_K~42.6-44.6 erg
s^{-1}. However, the minimum possible value of the ratio between the mechanical
power and bolometric luminosity is constrained to be comparable or higher than
the minimum required by simulations of feedback induced by winds/outflows.
Therefore, this work demonstrates that UFOs are indeed capable to provide a
significant contribution to the AGN cosmological feedback, in agreement with
theoretical expectations and the recent observation of interactions between AGN
outflows and the interstellar medium in several Seyferts galaxies.
