Regularization of hydroelectric reservoir levels through hydro and solar energy complementarity

Hydrological changes during prolonged droughts, as verified in the last two decades in Brazil, may reduce the level of hydroelectric reservoirs to the point that energy rationings become necessary. Such fluctuations, have been mainly complemented by thermo power, which is much more expensive and polluting. This work addresses the possibility of complementing the hydro system with solar energy. Daily-accumulated solar radiation from Sao Paulo, covering the period from 1961 to 2012, is used to evaluate the seasonal and interannual variability of solar power generation. The computed solar energy is applied in a hybrid solar-hydro model, where the turbine outflow is reduced accordingly to the solar power production, so that storage is improved in the long-term. The study region is Itumbiara reservoir in Brazil's Parana hydrographic basin. Results suggest that this hybrid system should improve the reservoir ability to confront interannual climate variability.