Absolute sustainability assessment of the power generation sector: a prospective insight towards the Chilean decarbonization targets

Assessing the environmental performance of systems from an absolute perspective is a recent trend for achieving a sustainable world. We present a framework for evaluating different power generation scenarios for Chile and their effects in terms of absolute sustainability performance. In this context, seven energy transition scenarios to 2060 are analyzed, including a business-as-usual scenario, high fossil fuel prices, climatic variability in terms of extreme droughts, a fully renewable system, different levels of hydrogen production, and a conservative case considering a low growth in electricity demand. The scenarios were modeled using the Open Source Energy Modeling System (OSeMOSYS), while environmental impacts were calculated using life cycle assessment methodology for five midpoint categories: global warming, freshwater eutrophication, marine eutrophication, ozone depletion, and water consumption. The planetary boundaries were calculated following a top-down approach under different downscaling-upscaling methods. Electricity demand ranges from 121 TWh in the conservative scenario to 353 TWh in the case of high (2.72 Mton) hydrogen production by 2060. For the remaining scenarios, electricity demand is around 205 TWh, aligned with projections from the Chilean government. In terms of environmental impacts, all prospective scenarios showed an average reduction of 66 % across all evaluated categories, shifting the main contributor to these impacts from fossil fuels (baseline scenario) to photovoltaic and wind energy. Although none of the scenarios fully operate within the safe operating space of the planetary boundaries, a fully renewable matrix and a conservative increase in electricity demand are identified as the most favorable scenarios. To operate within the planetary boundaries across all categories, the Chilean electricity mix must not only increase the share of renewable sources but also reduce per capita electricity consumption by up to one-half by 2060, relying exclusively on renewable sources. This research is expected to have implications for policymaking and research on the transition of power generation towards the climate targets of Chile.