From electricity to economy-wide Net-Zero: Comparative analysis of global energy pathways

The transition to Net Zero (NZ) energy systems has become a global priority for combating climate change and achieving sustainable energy systems. This paper presents a systematic review of national NZ electricity and energy system studies, with a primary focus on country-based modeling practices rather than purely academic literature. The review highlights how NZ pathways across nations reflect their unique energy resources, policy priorities, technological capabilities, and socio-economic contexts. Drawing from studies conducted after the Paris Agreement, the paper classifies NZ work into four categories: (I) clean electricity (CE) system studies, (II) NZ electricity system studies, (III) economy-wide NZ studies, and (IV) worldwide NZ economy studies. For each category, it examines the modeling frameworks used, the treatment of key technologies, and the integration of policy and market considerations. The analysis highlights significant differences in assumptions, time horizons, technology portfolios, and the treatment of grid reliability, flexibility, and seasonal balancing. By synthesizing results from multiple countries, including the United States, Japan, South Korea, China, the UK, Sweden, Thailand, France, Canada, Australia, Colombia, Indonesia, Vietnam, and EU member states, the paper identifies common challenges such as long-duration storage needs, transmission expansion, and operational stability under high inverter-based resource penetration. The findings reveal that while renewable energy and storage dominate most NZ strategies, achieving reliable and cost-effective transitions will require integrated planning across sectors, coordinated infrastructure investment, and context-specific policy design. This country-comparative perspective offers insights for policymakers, system planners, and researchers seeking to adapt global NZ strategies to national realities.