Projection of Climate Change and Consumptive Demands Projections Impacts on Hydropower Generation in the São Francisco River Basin, Brazil

Abstract

Climate change impacts may influence hydropower generation, especially with the intensification of extreme events and growing demand. In this study, we analyzed future hydroelectric generation using a set of scenarios considering both climate change and consumptive demands in the São Francisco River Basin. This project will increase consumptive demands for the coming decades. Five models from the recently released Coupled Model Intercomparison Project Phase 6 and two scenarios, SSP2-4.5 and SSP5-8.5, were considered to estimate climate change projections. The affluent natural flows, regulated flows, and the hydroelectric energy generated were estimated for four multi-purpose reservoirs considering all existing and new demands. The conjunction of scenarios indicated a possible significant reduction in water availability, increased consumptive demands, especially for irrigation, and reduced power generation. Only at the Sobradinho hydroelectric plant, the decrease ranged from −30% to −50% for the period 2021 to 2050 compared to the historical period (1901 to 2000). The results can provide insights into future energy generation and water resources management in the basin.

Impact of Climate Change and Consumptive Demands on the Performance of São Francisco River Reservoirs, Brazil

“…However, this new demand may increase existing water conflicts, especially during extreme events, such as the recent drought from 2012 to 2018, when water supply to urban areas was prioritized according to the federal water resources law (law no. 9433/97), as well as the production of food with irrigation, to the detriment of hydroelectric power generation, which was reduced from 87.7% in 2011 to 21% in 2017 of the total electricity demand of the region [5].…”

“…Regions that already have a history of recurrent and prolonged droughts, such as the Northeast region of Brazil (NEB), may experience this problem even more frequently, with an increase in temperatures between 4 • C and 5 • C, and a possible reduction in rainfall, with percentage anomalies ranging between −20% and 20% in the most pessimistic scenarios in the coming decades [3]. Considering this, it is possible that the outflows of the main river basins will decrease between 60% and 90% [3][4][5].…”

“…The São Francisco River is the main water system in the NEB region, being responsible for supplying water for multiple uses (consumer and non-consumer), such as human supply, irrigation, industry and navigation, among others. Among the consumptive uses, irrigation has been the predominant demand in most of the reservoirs that make up the São Francisco River Basin (SFRB) [5].…”

“…This hypothesis has been tested in several studies [5,[7][8][9]. They showed that climate change together with increased water demands bring significant impacts to reservoirs.…”

Drought Assessment in São Francisco River Basin, Brazil: Characterization through SPI and Associated Anomalous Climate Patterns

“…For the next decades, climate projections also show an increase in the water deficit, a reduction of the flow in the basin, and, as consequence, a reduction of almost 60% in the annual average of energy generated by hydro power plants in the SFRB. These projections suggest that the region would become more susceptible to drier conditions [33,[64][65][66].…”