Simulation of PV Variability as a Function of PV Generation and Plant Size: Preprint

Research output: Contribution to conferencePaper


The deployment of photovoltaic (PV) systems continues to show significant expansion; however, this growth has brought added attention to issues around the variability of the solar resource. Both spatial and temporal variability exist. Temporal scales can range from the sub-second to multiyear, whereas spatial scales can range from a few meters to tens of kilometers. There are multiple methods described in the literature to quantify PV variability at various spatial and temporal scales. This study focuses on short-term temporal variability and uses similar approaches with the addition of PV plant size a parameter to quantify variability. The method employed here incorporates the normalization of clear- and cloudy-sky conditions and PV plant size to quantify nominal variability metrics. The distribution and fluctuations of these metrics provide relevant information that is useful for system operations. The National Solar Radiation Database (NSRDB) is used to simulate PV variability as a function of PV generation and plant size. Hypothetical but realistic system information at 33 locations is used to model PV generation by feeding NSRDB solar irradiance data to the National Renewable Energy Laboratory’s System Advisor Model (SAM). Over the selected region, it is found that the aggregated ramp rates for the 1-minute data are associated with standard deviations ranging from 0.002–0.055 on a daily basis; however, hourly intervals induce higher aggregated ramp rates than the other timescales. Even though minute-to-minute variations are significant for the 1-minute timescale, the standard deviation aggregated into a daily metric is smaller because of the cancellation of values.
Original languageAmerican English
Number of pages7
StatePublished - 2021
Event48th IEEE Photovoltaic Specialists Conference (PVSC 48) -
Duration: 20 Jun 202025 Jun 2020


Conference48th IEEE Photovoltaic Specialists Conference (PVSC 48)

Bibliographical note

See NREL/CP-5D00-81132 for paper as published in proceedings

NREL Publication Number

  • NREL/CP-5D00-79710


  • irradiance
  • National Solar Radiation Database
  • photovoltaic systems
  • PV
  • SAM
  • solar energy
  • System Advisor Model


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