In recent years, the Brazilian electricity sector has seen a considerable reduction in hydroelectric production and an increase in dependence on the complementation of thermoelectric power plants to meet the energy demand. This issue has led to an increase in greenhouse gas emissions, which has intensified climate change and modified rainfall regimes in several regions of the country, as well as increased the cost of energy. The use of floating PV plants in coordinated operation with hydroelectric plants can establish a mutual compensation between these sources and replace a large portion of the energy that comes from thermal sources, thereby reducing the dependence on thermoelectric energy for hydropower complementation. Thus, this paper presents a procedure for technically and economically sizing floating PV plants for coordinated operation with hydroelectric plants. A case study focused on the hydroelectric plants of the São Francisco River basin, where there has been intense droughts and increased dependence on thermoelectric energy for hydropower complementation. The results of the optimized design show that a PV panel tilt of approximately 3º can generate energy at the lowest cost (from R$298.00/MWh to R$312.00/MWh, depending on the geographical location of the FLOATING PV platform on the reservoir). From an energy perspective, the average energy gain generated by the hydroelectric plant after adding the floating PV generation was 76%, whereas the capacity factor increased by 17.3% on average. In terms of equivalent inflow, the PV source has a seasonal profile that 3 compliments the natural inflow of the river. Overall, the proposed coordinated operation could replace much of the thermoelectric generation in Brazil.

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Inefficiency of sanitation companies’ operation procedures threatens the population’s future supplies. Thus, it is essential to increase water and energy efficiency in order to meet future demand. Optimization techniques are important tools for the analysis of complex problems, as in distribution networks for supply. Currently, genetic algorithms are recognized by their application in literature. In this regard, an optimization model of water distribution network is proposed, using genetic algorithms. The difference in this research is a methodology based on in-depth analysis of results, using statistics and the design of experimental tools and software. The proposed technique was applied to a theoretical network developed for the study. Preliminary simulations were accomplished using EPANET, representing the main causes of water and energy inefficiency in Brazilian sanitation companies. Some parameters were changed in applying this model, such as reservoir level, pipe diameter, pumping pressures, and valve-closing percentage. These values were established by the design of experimental techniques. As output, we obtained the equation of response surface, optimized, which resulted in values of established hydraulic parameters. From these data, the obtained parameters in computational optimization algorithms were applied, resulting in losses of 26.61%, improvement of 16.19 p.p. with regard to the network without optimization, establishing an operational strategy involving three pumps and a pressure-reducing valve.  We conclude that the association of optimization and the planning of experimental techniques constitutes an encouraging method to deal with the complexity of water-distribution network optimization.