We analyze SDSS spectra of 568 obscured luminous quasars .
The [ OIII ] \lambda 5007Å emission line shows blueshifts and blue excess , indicating that some of the narrow-line gas is undergoing an organized outflow .
The velocity width containing 90 % of line power ranges from 370 to 4780 km/sec , suggesting outflow velocities up to \sim 2000 km/sec , and is strongly correlated with the radio luminosity among the radio-quiet quasars .
We propose that radio emission in radio-quiet quasars is due to relativistic particles accelerated in the shocks within the quasar-driven outflows ; star formation in quasar hosts is insufficient to explain the observed radio emission .
The median radio luminosity of the sample of \nu L _ { \nu } [ 1.4GHz ] = 10 ^ { 40 } erg/sec suggests a median kinetic luminosity of the quasar-driven wind of L _ { wind } = 3 \times 10 ^ { 44 } erg/sec , or about 4 % of the estimated median bolometric luminosity L _ { bol } = 8 \times 10 ^ { 45 } erg/sec .
Furthermore , the velocity width of [ OIII ] is positively correlated with mid-infrared luminosity , which suggests that outflows are ultimately driven by the radiative output of the quasar .
Emission lines characteristic of shocks in quasi-neutral medium increase with the velocity of the outflow , which we take as evidence of quasar-driven winds propagating into the interstellar medium of the host galaxy .
Quasar feedback appears to operate above the threshold luminosity of L _ { bol } \sim 3 \times 10 ^ { 45 } erg/sec .