What will it take to get to net-zero emissions in California?

In this work, a new modeling tool called DECAL (DEcarbonize CALifornia) is developed and used to evaluate what it will take to reach California's climate mandate of net-zero emissions by 2045. DECAL is a scenario-based model that projects emissions, society-wide costs, and resource consumption in response to user-defined inputs. DECAL has sufficient detail to model true net-zero pathways and reveal fine-grain technology insights. Using DECAL, we find the State can achieve 52 % of the emissions abatement needed to meet net-zero by 2045 using technologies that are already commercially available, such as electric vehicles, heat pumps, and renewable electricity & storage. While these technologies are mature, the speed and scale of deployment required will still pose significant practical challenges if not technical ones. In addition, we find that 25 % of emissions abatement will come from technologies currently at early-stage deployment, and 23 % from technologies at research scale, motivating the continued research & development of these technologies, including zero-emission heavy-duty vehicles, carbon capture & sequestration, clean industrial heating, low global warming potential refrigerants, and direct air capture. Significant carbon dioxide removal will also be needed for California to meet its net-zero target on time, at least 45 Mt/yr and more likely up to 75 Mt/yr by 2045. Accelerating deployment of mature technologies can further reduce the need for carbon removal, nevertheless, establishing enforceable carbon removal targets and conducting policy planning to make said goals a reality will be needed if California is to meet its net-zero by 2045 goal. • A new decarbonization pathways model for California was developed called DECAL. • California can get halfway to net-zero by scaling existing technologies. • Several technologies at early stage development or research scale will be needed. • Challenges include practical deployment barriers, lag-time, & resource constraints. • Significant carbon dioxide removal will be needed to meet net-zero by 2045.