  Using a scattering matrix approach we study transport in coherent conductors
driven by a time-periodic bias voltage. We investigate the role of
electron-like and hole-like excitations created by the driving in the energy
current noise and we reconcile previous studies on charge current noise in this
kind of systems. The energy noise reveals additional features due to
electron-hole correlations. These features should be observable in power
fluctuations. In particular, we show results for the case of a harmonic and
bi-harmonic driving and of Lorentzian pulses applied to a two-terminal
conductor, addressing the recent experiments of Refs. 1 and 2.
