Journal Article

Identifying Robust Decarbonization Pathways for the Western U.S. Electric Power System Under Deep Climate Uncertainty

Craig, Michael T., Sundar, Srihari, Lehner, Flavio, Voisin, Nathalie

2024

Overview

Climate change threatens the resource adequacy of future power systems. Existing research and practice lack frameworks for identifying decarbonization pathways that are robust to climate‐related uncertainty. We create such an analytical framework, then use it to assess the robustness of alternative pathways to achieving 60% emissions reductions from 2022 levels by 2040 for the Western U.S. power system. Our framework integrates power system planning and resource adequacy models with 100 climate realizations from a large climate ensemble. Climate realizations drive electricity demand; thermal plant availability; and wind, solar, and hydropower generation. Among five initial decarbonization pathways, all exhibit modest to significant resource adequacy failures under climate realizations in 2040, but certain pathways experience significantly less resource adequacy failures at little additional cost relative to other pathways. By identifying and planning for an extreme climate realization that drives the largest resource adequacy failures across our pathways, we produce a new decarbonization pathway that has no resource adequacy failures under any climate realizations. This new pathway is roughly 5% more expensive than other pathways due to greater capacity investment, and shifts investment from wind to solar and natural gas generators. Our analysis suggests modest increases in investment costs can add significant robustness against climate change in decarbonizing power systems. Our framework can help power system planners adapt to climate change by stress testing future plans to potential climate realizations, and offers a unique bridge between energy system and climate modeling. Plain Language Summary Over the past few years, large power outage events in California and Texas have underscored the vulnerability of our power systems to extreme weather. By increasing the intensity and frequency of extreme weather, climate change could lead to more power outages. In response, power system planners are grappling with how to plan for extreme weather and climate change when making investment decisions, such as in wind and solar power. In our research, we build and apply a new analytical framework for making power system investment decisions under climate change. Our framework draws on a hundred realizations of future climate, and integrates weather in those realizations with power system models that make investment decisions and explore the risk of power outages. We find five alternative investment pathways all could suffer from moderate to significant power outages under possible climate realizations by 2040. But by identifying what realizations drive outage risk in these pathways, we construct a new pathway that does not exhibit outage risks to our future climate realizations. Overall, these insights demonstrate the value of our new analytical framework for making better investment decisions under uncertainty posed by climate change. Key Points We identify a decarbonization pathway for the power system that is robust to future climate realizations Our framework is extensible to long‐term planning by utilities, regions, and regulators Large climate ensembles expose significant resource adequacy vulnerabilities in alternative decarbonization pathways

• Publisher: John Wiley & Sons, Inc,American Geophysical Union (AGU),Wiley
• Subject: Adequacy / Atmospheric carbon dioxide / capacity expansion / Climate / Climate adaptation / Climate change / Climate change adaptation / Climate models / Climatic extremes / Computer simulation / Computer-generated environments / Control / Decarbonization / Decision making / Economic aspects / Electric power / Electric power demand / Electric power generation / Electric power systems / Electricity / Electricity distribution / Emissions / Emissions control / Energy costs / ENERGY PLANNING, POLICY, AND ECONOMY / Environmental aspects / Failure / Gas generators / Hydroelectric power / Hydroelectric power generation / Long term planning / Natural gas / Power plants / power system planning / resource adequacy / robust decision-making / Robustness / single model initial‐condition large ensemble / Uncertainty analysis / Wind / Wind stress