Integrating solar and wind power: Examining transition pathways, integration stressors and policy responses across 41 countries

The feasibility of a rapid and seamless transition to 100% renewable energy systems has been debated: Solar and wind are cheap and widely available, but their variability presents challenges for their integration into existing energy systems. Energy systems modeling and engineering literatures highlight technologically feasible solutions to address these challenges, but do not address the political mechanisms of implementing these solutions. Here, we bridge a techno-economic understanding of VRE integration challenges with socio-technical insights into policy-driven technology change. We mobilize empirical evidence from 41 countries across four continents. First, we develop a method to trace countries’ progress through six phases of VRE integration, delineated by changes in hourly power generation patterns as shares of VRE generation increase. Second, we examine how system pressures like curtailment and declining VRE market value evolve throughout these phases. Third, we build an AI-assisted approach to classify public energy policies and examine policy change throughout the VRE integration phases. Finally, we examine the relationship between integration pressures, policy responses and growth rates of solar PV and wind power. We find that most countries are in Phase 3 of VRE integration, where solar and wind variability forces conventional generators to operate at times of low VRE generation. Only few advanced economies have progressed to phases 4 or 5. The annual rate of integration policy introduction tends to be highest in phase 3, when VRE generation begins to significantly impact power systems. Governments implement a mix of integration policies, but focus on different measures over time: for example, the share of hydrogen policies has increased in recent years.