Renewable Electricity Transition, Waste System Modernization, and Sustainable Methane Mitigation: Global Evidence on Governance-Conditioned Co-Benefits

Achieving sustainability requires that energy transition generates measurable environmental benefits beyond the power sector, yet it remains unclear whether renewable electricity expansion is associated with lower waste sector methane intensity, a major source of short-lived climate forcing. Using a global country–year panel and two-way fixed effects, we examine whether this relationship, and its sustainability implications, varies with development stage, institutional quality, and waste system characteristics. We find no robust inverted-U Environmental Kuznets Curve once country and year fixed effects are included. Instead, higher renewable electricity shares are consistently associated with lower waste sector methane intensity, and this association strengthens with income. A 10-percentage-point increase in renewable share corresponds to about 2.7%, 4.2%, and 6.0% lower intensity at the 25th, 50th, and 75th income percentiles. The negative association is stronger in countries with higher governance quality, while waste management capacity and organic waste composition reveal additional heterogeneity in the observed association. Overall, electricity decarbonization alone is not a uniform instrument for reducing diffuse biological emissions; sustainable methane mitigation likely requires coordinated governance linking renewable transition with waste system modernization.