A low-cost two-camera sky-imager ground-based intra-hour solar forecasting system with cloud base height estimation capabilities working in a smart grid

This work presents the first results of a low-cost intra-hour solar forecasting system based on two sky-imagers deployed last year in La Graciosa Island (Canary Islands, Spain), in the framework of the GRACIOSA project. The system identifies the clouds on the images, predict their movement and deliver irradiance predictions in the 2.5 and 5-minutes forecast horizon. A procedure to obtain cloud base height estimations using both cameras is also implemented in the system. First evaluations show that, although there is still room for improvement regarding other metrics, the forecast system outperforms persistence model when mean absolute error is considered.