Integrating climate-driven hydropower variability into long-term energy planning: A Bolivian case study under El Niño and La Niña scenarios

As climate change effects become more evident worldwide, particularly regarding the variation in hydro resources availability, quantifying their potential impacts is critical to enable adequate adaptation strategies and facilitate planning efforts. In this sense, countries heavily reliant on hydropower must assess and integrate the implications of this variability to ensure a reliable electricity supply. Considering Bolivia as a case study, the impact of alternative hydro availability scenarios is evaluated through the analysis of extreme weather conditions associated with El Niño and La Niña events. To this end, a modeling framework is presented that combines global precipitation projections downscaled to a local level, with which three scenarios (Control, El Niño, and La Niña) are developed for 2030, 2040, and 2050. These scenarios are later analyzed using a cost-optimization energy model tailored to Bolivia, developed with PyPSA-Earth, which allows the representation of region-specific conditions with hourly resolution, both for hydro resources availability and electrical components. Results indicate that both El Niño and La Niña events can reduce hydropower availability significantly, by up to 37 % compared to average years, with neither of them being strictly linked to a higher reduction in hydropower generation. Regarding the operation of the system, it is seen that Bolivia’s legacy power plants can handle hydrological variability until 2040. However, the decommissioning of fossil capacity by 2050 significantly increases system vulnerability. As a result, deployment of flexible technologies and battery storage will play a key role in addressing both long-term capacity adequacy and short-term flexibility.