Short- to seasonal-range streamflow forecasting in reservoirs of the Brazilian National Interconnect Electric Power System

The Electric Energy Company of Parana (COPEL GeT), the Meteorological System of Parana (SIMEPAR) and RHAMA Consulting company are undertaking the research project PD-6491-0503/2018 for the development of a hydrometeorological seasonal forecasting for Brazilian reservoirs. The project, sponsored by the National Agency for Electric Energy (ANEEL) under its research and development programme, aims the forecasting of streamflow, at temporal scales ranging from 1 to 270 days which are integrated by the National Power System Operator (ONS) through its Interconnected System (SIN). The SIN is composed of more than 150 hydropower plants and reservoirs located over a wide range of climate and hydrological conditions. It is responsible for more than 50% of the total electricity produced in the country. In this work we describe the overall characteristics of this project, comprising its structure, main research results and its usefulness for assisting decision makers in the field of energy, as will be demonstrated through some application sceneries. We used the precipitation short-medium-range, sub-seasonal, and seasonal ECMWF forecasts as input to a continental-scale, hydrologic hydrodynamic model (MGB-SA) to produce streamflow forecasts for the SIN hydropower reservoirs. On the short-medium-range horizon we used persistency and the control member as benchmarks, while in the sub-seasonal and seasonal we used the ESP. On the short-medium-range and sub-seasonal, the ensemble average performance was superior to the control deterministic predictions for ECMWF (MGB-SA), both for the prediction quality metrics and for the event discrimination metrics. On the seasonal forecast, the ECMWF results were consistently superior to the benchmark on the first lead time month, decreasing performance with the horizon. The results of the project are expected to benefit energy generation planning, routine and emergency hydraulic operation (e.g., flood and droughts), as well as energy commercialization procedures in the country.