This data is derived by National Grid ESO using REMIT Data published from the BMRS. The data provides three levels of aggregation: National Output Usable (NOU), Fuel Output Usable (FOU) and Balancing Mechanism Unit Output Usable (UOU). For more information, see https://developer.data.elexon.co.uk/api-details#api=prod-insol-insights-apim&operation=get-generation-availability-summary-14d