Roadmaps to net-zero emissions systems: Emerging insights and modeling challenges

Understanding economic and technical characteristics of net-zero emissions energy systems is important, given the growing number of national, subnational, and company net-zero targets. Emerging modeling studies examine how to achieve these net-zero goals, but differences across countries, model structures, and input assumptions make comparisons difficult. This perspective reviews insights from country-level studies on net-zero emissions systems. There is robust agreement on near-term low regrets'' strategies: rapid reduction of coal generation and expansion of renewables in the power sector; lower fossil fuel use; end-use efficiency improvements; electrification of end uses especially in transportation; and research, development, and deployment to buy down learning curves for emerging technologies that might be valuable for deeper decarbonization. However, although nearer-term trends are qualitatively similar, studies exhibit variation in decarbonization strategies, especially as net-zero goals are approached. Net-zero emissions targets lead to shifts toward clean electricity and declines in fossil fuel use, though magnitudes of these changes vary considerably across countries, models, and scenarios. This work also highlights modeling and analysis needs moving forward, including ways to provide more actionable information for stakeholders and research gaps where collaborations are increasingly valuable.

Automated summary

Understanding the economic and technical characteristics of net-zero emissions energy systems is crucial due to the increasing number of net-zero targets set by governments, regions, and companies. There is a general consensus on near-term low regrets strategies to achieve net-zero goals, including reducing coal generation, increasing renewable energy use, improving energy efficiency, electrifying end-use sectors, and investing in emerging technologies. However, differences in decarbonization strategies emerge as countries approach their net-zero emissions targets, with shifts towards clean electricity and reductions in fossil fuel use varying significantly across different countries, models, and scenarios. Collaborations in research are increasingly valuable to address modeling and analysis needs for stakeholders.