Case study for hydro–photovoltaic power generation in Brazilian semiarid region

What is it about?

Hydropower is currently the primary energy resource to service the Brazilian electricity sector. However, the dry seasons in the Brazilian semiarid region have become longer due to climate variability, and they have affected the operation of hydropower plants during the last decade. Brazil has a growing energy demand, and energy mix diversification is essential to meet the power capacity required to support sustainable development. Investments in photovoltaic power plants are already a robust strategy to foster a new cycle of socioeconomic development based on a low-carbon economy. Hybrid power generation using hydro- and solar energy resources can be an alternative source due to the seasonal complementarity between them in the Brazilian semiarid region. During the dry periods, the photovoltaic power plant can replace hydropower generation. The present study aimed to evaluate the contribution of a solar photovoltaic plant to increase power generation in the Sobradinho hydropower plant operating in the São Francisco River, the most important water resource in the Brazilian semiarid region. The results showed that the PV power plant contributes to saving water for other multiple usages and avoids emissions of greenhouse gases by thermal power plants in long periods of intense drought. According to the simulation results for the 2013–2015 period, the PV plant would add around 8350 GWh to the actual power generated in Sobradinho using an area smaller than 0.5% of its water reservoir surface. In addition, hybrid power generation would avoid emissions around 27.106 t CO2 released into the atmosphere by thermal power plants using fossil fuels for 3 years.

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Why is it important?

The semiarid region in Northeastern Brazil experiences drought seasons caused by the typical local rainfall regime. The São Francisco River is the primary water resource for electricity generation as well as for several purposes in the semiarid region including urban supply, industrial usages, and agriculture irrigation. The eight HPPs installed along the São Francisco River are usually responsible for about 9.8% of the installed electricity capacity in Brazil. However, there was a significant decline in electricity generation in the São Francisco River basin during the extended periods of intense droughts, such as the one observed between 2013 and 2015. Under such conditions, thermal power plants started operating to ensure the security of the Brazilian electricity system. Brazil needs to diversify its energy mix through power generation technologies that are clean and less harmful to the environment. The Brazilian semiarid region also stands out for the highest incidence of solar irradiance in the Brazilian territory. There is evidence that taking advantage of a solar energy resource is a good alternative concerning the social and economic development of the region.

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