This work presents an Energy Storage Systems (ESS) sizing strategy, that allows grid connected PV systems to provide peak-shaved maximum-power-Ramp-Rate (RR) compliant power while storing exceeding power. For this purpose power generation and power loss caused by complying several RR restrictions were estimated. The estimation is based on irradiance and temperature real data from a measuring station located in the Atacama desert in Chile. The presented sizing strategy is based on Discrete Wavelet Transform (DWT) and allows to obtain an energy and power ESS sizing matching different criterion. Moreover, the selection of the ad-hoc wavelet and decomposition level, required filter the estimated PV power, is also presented.