Large hydropower, decarbonisation and climate change uncertainty: Modelling power sector pathways for Ecuador

Hydropower plays a critical role in global, South American and Ecuadorian energy policy and for achieving Nationally Determined Contributions (NDCs) aiming to reduce greenhouse gas emissions. However, long-term climatic changes may affect the role of hydropower in meeting energy and climate policy objectives. The effects of climate change on runoff availability for hydropower generation are largely uncertain. This paper uses climate change scenarios derived from a large ensemble of Global Circulation Models as input for an energy system optimisation model (TIMES-EC) to examine least-cost options for the hydropower-dominated Ecuadorian power system in the period to 2050. This is done in the context of three policy cases in order to assess trade-offs between power system configuration, emissions and costs. The results show that in the long-term hydropower will remain as one of the most cost-effective and low emission technologies in the Ecuadorian power sector. However, constraints on deployment and uncertainty around climate change impacts could hinder its ability to contribute to the fulfilment of NDC targets, as well as create uncertainty around long-term power system costs. Strategies to hedge against these risks will likely require that hydropower expansion be complemented by alternative sources, namely incremental shares of thermoelectric generation with natural gas, biomass and geothermal energy.