Abstract: The measurements of spatial correlations of the cluster kinetic Sunyaev Zeldovich (KSZ) flux can in principle allow the measurement of the cluster peculiar velocity power spectrum. Future large sky coverage KSZ surveys may allow a peculiar velocity power spectrum estimates of an accuracy reaching ~10%. In contrast with conventional techniques, this new method does not require measurements of the thermal SZ signal or the X-ray temperature. Moreover, this method is optimal in the sense that the expected systematic errors are always subdominant to statistical errors on all scales and redshifts of interest.