Grid-Scale BESS Operational Datasets for Battery Modeling Research

Research and development across the battery energy storage system (BESS) field depends on real-world operational data, yet standardized collections of grid-scale BESS datasets are largely absent from the literature. Laboratory testing of single cells does not capture several factors present in field operation, including variable duty cycles, auxiliary loads, battery management system (BMS) estimation errors, string imbalances, and communication lags. This article releases a collection of datasets from 12 grid-scale BESS spanning three chemistry families: lithium iron phosphate (LFP), nickel manganese cobalt (NMC), and vanadium redox flow (VRF). The datasets were collected by Pacific Northwest National Laboratory (PNNL) through the Washington Clean Energy Fund (WACEF) Grid Modernization project and through collaboration with the Electric Power Research Institute (EPRI). Each WACEF system was subjected to reference performance testing following U.S. Department of Energy protocols and to use case duty cycles representative of grid services including peak shaving, frequency regulation, arbitrage, and outage mitigation. We describe each dataset's system specifications, metering configuration, available data tags, and known issues arising from BMS behavior, data collection infrastructure, and operational anomalies. Power values are normalized to C-rates and timestamps are reported as elapsed time, which allows cross-system comparison and keeps confidential system specifications out of the released data. A data quality flag marks observations affected by metering issues or maintenance. The datasets are released with per-system documentation of specifications, metering, and known data issues.