Solar power as an alternative energy source in Hawai'i has grown in recent years [1], with increasing amounts of photovoltaic panels found statewide. Power resource management and grid stability require that the variability in irradiance, hence, solar power coming into the electric grid be understood. The aim of this study is to produce an irradiance dataset for Oahu, Hawai'i, containing temporal and spatial variability, so it can be used in modeling power generation. Images from the Geostationary Operational Environmental Satellite are used to estimate surface irradiance within the Heliosat method and are validated against ground-based pyranometer measurements. The diurnal cycle was then removed to assess the accuracy of the Heliosat method in estimating atmospheric attenuation. Lastly, the irradiance data was converted into DC power to consider the dataset in terms of power generation. The irradiance dataset produced has RMSE values of 15-30% depending on location, with correction for viewing angle discrepancies found to improve the performance. Variability on sub hourly, diurnal, monthly and yearly time scales are found within the dataset, as well as events such as an El Nino year, a La Nina year and Kona lows, together with a spatial distribution consistent with previous research. (C) 2018 Elsevier Ltd. All rights reserved.