Centrais fotovoltaicas consorciadas à centrais geradoras hidrelétricas (CGHS) - um estudo de caso

Abstract

The use of photovoltaic systems installed over water has some advantages over systems installed on land, roofs, etc., such as cooling the panels, increasing their efficiency, avoided cost in land acquisition/leasing, reduced evaporation in the reservoir and decrease in CO2 emissions. It is considered that the use of Floating Photovoltaic Plants (CFVF) in consortium with Hydroelectric Power Plants (UHEs) also has as a positive point its low cost of connection to the electricity grid due to the existence, generally, of a connection structure for the UHEs. The system is subdivided into three parts: generator subsystem, composed of panels and assembly structures; power conditioning subsystem, consisting of the photovoltaic inverter and its controls, and an energy store, which in this case would be the reservoir itself that holds the water to be turbined. In this way, the reservoir works as an “energy store” and the hydroelectric generators will produce the energy, for example, during peak demand hours and/or when there is low solar irradiation. For the development of this work it is proposed to use structured Excel spreadsheets with simple data entries that allow to simulate the generation of CGHs against the investigated basic arrangement configurations and the availability of photovoltaic energy against the local availability. The case study presents a proposal for the installation of a 3.375 MW Floating Photovoltaic Plant (CFVF) in the auxiliary reservoir for regularization of the REPI Hydroelectric Generating Plant (CGH REPI), located in the city of Wenceslau Braz / MG. The plant supplies energy to the Military Material Industry (IMBEL), falling under the category of Self Producer of Energy. The results obtained demonstrate that an inclination of the PV panel of approximately 5° can generate energy with the lowest cost, of R$ 588.00/MWh, occupying only 23% of the auxiliary reservoir and avoiding the evaporation of 46,956.18 m3 of water per year. From an energy point of view, the average energy gain generated by the hydroelectric plant after the addition of floating PV generation would be 53%. The payback period for the investment was estimated in 7 years with initial costs of R$25,038,499.20 for the energy sale price of R$0.78/kWh. And CO2| emissions can be offset after 3 years and 10 months of CFVF operation.