Comparing ramp rates from large and small PV systems, and selection of batteries for ramp rate control

We compare the AC power fluctuations from a 1.6 MW and a 2 kW photovoltaic (PV) system. Both of these PV generating stations exhibit fluctuations exceeding 50% of their rated capacity in under 10 seconds. The smaller system can fluctuate more rapidly, exhibiting 50% dropouts in 3 seconds. Although the MW-scale system covers 4000 times as much ground area, the bandwidth of the fluctuations is remarkably similar. We explore explanations for this observation, and we discuss the impact of this on battery sizing.