Journal of Sustainable Development; Vol. 11, No. 1; 2018 ISSN 1913-9063 E-ISSN 1913-9071 Published by Canadian Center of Science and Education 140 Impacts of Climate Change on Hydroelectric Power Generation – A Case Study Focused in the Paranapanema Basin, Brazil Rafael de Oliveira Tiezzi¹, Nathália Duarte Braz Vieira², André Felipe Simões³, Homero Fonseca Filho 4 , Ednílson Viana 4 , Dominique Mouette 4 & Mariana Soares Domingues 4 ¹ Assistant Professor at Federal University of Alfenas – UNIFAL, Brazil ² PhD student in Energy Planning Systems of State University of Campinas – UNICAMP, Brazil ³Associate Professor at School of Arts, Sciences and Humanities of University of São Paulo – EACH/USP, Brazil 4 Assistant Professor at School of Arts, Sciences and Humanities of University of São Paulo – EACH/USP, Brazil Correspondence: Nathália Vieira, Mechanical Engineering Department, University of Campinas, Campinas, SP, Brazil. Tel: 55-019-98444-4595. E-mail: nathaliadbv@unifei.edu.br Received: September 14, 2017 Accepted: January 10, 2018 Online Published: January 30, 2018 doi:10.5539/jsd.v11n1p140 URL: https://doi.org/10.5539/jsd.v11n1p140 Abstract Climate change is taking special attention among the economic agents, especially due to the uncertainties and risks associated with it. In countries with a significant share of renewables in their energy matrix, this phenomenon implies on challenges for the energy planning in future scenarios. In this context, this study establishes a correlation between energy security and climate change by understanding the ability to generate hydroelectric power in large-scale hydroelectric (HEP) and small hydroelectric plants (SHP), in the Alto Paranapanema Basin (São Paulo, Brazil), a region with rainfall anomalies and water flow changes due to climate change. This region was chosen based on its future scenarios on climate change, especially those of rainfall anomalies and change in water flow, using the Soil Moisture Accounting Procedure (SMAP) mathematical model. The water flow was simulated in the HidroLab model, resulting in the generation of hydroelectric power. The results indicated a loss of generation capacity, that can be attributed to negative anomalies of rainfall and its direct influence on river flow, which is a fundamental factor in hydropower generation. Thus, this study draws attention to the importance of considering climate vulnerability in energy planning now and in the future. Keywords: climate change, impacts of climate variability, hydroelectric power generation in Brazil, rainfall variation, energy security 1. Introduction Global climate variability, especially climate change and global warming, has become a major concern for governments, NGOs, companies, and society in general as its impacts on economies, population, food production, and the environment. The Intergovernmental Panel on Climate Change (IPCC) was categorical in stating that the observed global warming of the past 50 years is due to the accumulation of greenhouse gases generated by human activities. These greenhouse gases, especially carbon dioxide and methane, have the highest atmospheric concentrations in the last 650 000 years of the history of the planet. The Fifth IPCC Report projected that by 2100 the mean global temperature could rise on average from 2°C to more than 4°C (IPCC, 2014). Consequently, the high latitudes and the equatorial Pacific are likely to experience an increase in annual mean precipitation. In many mid-latitude and subtropical dry regions, mean precipitation will likely decrease while in mid-latitude wet regions, mean precipitation will likely increase. Extreme precipitation events over most mid-latitude land masses and over wet tropical regions will very likely become more intense and more frequent as global mean surface temperature increases. Globally, in all scenarios studied by IPCC, it is likely that the area encompassed by monsoon systems will increase and monsoon precipitation is likely to intensify and El Niño-Southern Oscillation (ENSO) related precipitation variability on regional scales will likely intensify (IPCC, 2014). The energy use is dependent on natural resources, and the availability and reliability of renewable sources are function of climate conditions, which can vary according to global climate changes (Lucena, Szklo, Schaeffer & Dutra, 2010). Climatic variability and climate change effects impacts on water resources use and associated