The fluctuations in the power delivered to the grid remain a problem in photovoltaic grid-connected systems. Energy storage systems are proposed as a solution in order to comply with these standard power quality requirements. Due to their distinctive properties, supercapacitors can be considered as the most efficient energy storage systems available in the market today. Thus, their capability of fast charging and discharging and their high capacitance (hundred of farads) compared to the traditional ones have been the main reason of their massive integration in PV systems. This paper presents a comparison between a conventional capacitor and a supercapacitor used as DC-link in a PV grid connected system. The superiority of the supercapacitor is demonstrated through a performance evaluation based on simulation results.