Impacts of climate change and deforestation on hydropower planning in the Brazilian Amazon

The Amazon Basin is Brazil’s next frontier for hydropower, but alterations to the water cycle from climate change and deforestation could affect river flows fuelling electricity generation. This research investigated the effects of global and regional changes to the largest network of planned and existing dams within a single basin in the Amazon (the Tapajόs River), which altogether accounts for nearly 50% of the inventoried potential expansion in Brazil. Future hydrological conditions could delay the period of maximum daily generation by 22–29 d, worsening the mismatch between seasonal electricity supply and peak demand. Overall, climate change could decrease dry season hydropower potential by 430–312 GWh per month (−7.4 to −5.4%), while combined effects of deforestation could increase interannual variability from 548 to 713–926 GWh per month (+50% to +69%). Incorporating future change and coordinating dam operations should be a premise in energy planning that could help develop more resilient energy portfolios. Hydropower is important in Brazil, but climate change and deforestation are changing river flows. This study finds that future conditions will worsen a mismatch between seasonal electricity supply and peak demand.