Compound Drought-Heatwave Events: Brazil’s Energy Sector

Hydropower provides more than half of Brazil’s electricity, making the energy system sensitive to climate variability. Recent droughts have had severe impacts on hydropower generation, including the 2014/15 event that affected production in Southeast Brazil. Heatwaves in densely populated areas of the country can also drive an increase in energy demand for cooling. The co-occurrence of these drought and heatwaves events can be considered a spatially compound event which occur when interconnected locations experience hazards concurrently, amplifying impacts beyond that of the individual hazards. Therefore, these events represent a substantial risk to the energy security of Brazil.

This study investigates how the occurrence of these drought-heatwave compound events has changed since 2004. Impacts metrics, including the Standardised Precipitation Evapotranspiration Index and Cooling Degree Days derived from ERA5, combined with energy demand and energy production data were used to investigate both the univariate and compound nature of the changes observed, and the implications this has for the energy system. The results indicate that the nature of the most extreme compound events vary, and that a compound approach offers a more comprehensive assessment of climate impacts on the energy system than a univariate approach. These findings also have the potential to aid adaptation research by providing a basis to explore how climate-energy stress events may change under future climate projections.