Elia is Belgiumâ€™s high-voltage transmission system operator and a key player in the energy market and interconnected electricity system in Europe. The company has set up multiple initiatives promoting the development of an efficient, transparent and fair electricity market including integrating renewable energy sources.
Elia offers a REST API for programmatic access to their Solar Forecasting page. The page displays solar-PV generation forecasts, real-time estimations of actual solar-PV generation and historical solar-PV power data. API methods include GetRegions, GetChartDataForZone and GetCapacities. The API is free to use and there are no signup requirements.