Performance data from the NIST photovoltaic arrays and weather station

Abstract

In July 2012, the National Institute of Standards and Technology (NIST) completed construction of threephotovoltaic (PV) arrays on its Gaithersburg, MD campus. Comprehensive data acquisition systems were installed and an onsite weather station was also built to collect ancillary solar and meteorological measurements that are needed for the full characterization and modeling of the PV arrays. These datasets provide high-resolution, low-uncertainty, comprehensive PV performance and weather data for extended, continuous time periods. The creation of these datasets is fulfilling a need of the research and energy communities that few other datasets meet. Data from these systems have been collected for about three years at the time of this publication, between August 2014 and July 2017, and are being provided to the public via an online web portal for viewing and download. The three arrays on campus use the same monocrystalline silicon module but are mounted in different configurations: the Canopy Array is mounted on east/west facing canopies over a parking lot, the Ground Array is mounted on tilted ground supports in an open field, and the Roof Array is mounted on tilted, weighted racks on a flat building roof. There is a single inverter at each array that is connected to the local grid via the NIST campus grid. The arrays are instrumented with research-grade sensors measuring various electrical, temperature, and meteorological parameters. At each array there are wind, ambient temperature, and various solar measurements being conducted. There is also a comprehensive weather station installed on a nearby building. The weather station includes instruments measuring the various solar components, spectral curves, ultraviolet (UV) light and infrared radiation (IR) energy, and a full suite of standard weather conditions. Reference modules are also installed near the weather station in the same manner and orientations as those in the arrays. These modules are maximum power tracked, with the current-voltage (I-V) curves traced every minute. Cameras capture images of these reference modules, the arrays, and the entire sky.