ECO-FRESH Nigeria: Integrating Circular Bioenergy, Solar Cold Chains, and Agroecology for Methane Mitigation and Food Security.

ECO-FRESH Nigeria is an integrated circular food-system model linking organic waste–tobioenergy (anaerobic digestion), solar-assisted cold storage, and agroecological production support to address methane mitigation and food security simultaneously. We evaluated ECOFRESH using a mixed-methods, quasi-experimental design across three pilot hubs with matched comparison communities and baseline endline measurement over 12 months. Operational monitoring tracked waste diversion, biogas production, and cold-room reliability, while impact evaluation assessed postharvest losses, quality outcomes, farmgate prices, and incomes. Methane mitigation was quantified using a measurement, reporting, and verification (MRV) framework with sensitivity analysis. Average organic waste diverted was 5.1 t/day and biogas production 410 m³/day. Cold-room throughput averaged 6.8 t/day with 95.2% uptime and 92.3% temperature compliance. Difference-in-differences estimates show postharvest losses declined by 12.0 percentage points (95% CI: -14.3 to -9.7), accompanied by higher Grade A share and lower rejection rates (p < .001). Farmgate prices increased by ₦40/kg, and monthly net farm income rose by ₦20,700 (≈24% growth). MRV results estimate an annualized net climate benefit of 18,540 tCO₂e/year (range: 14,200–23,900). Impacts were broadly inclusive, though smaller for producers farthest from hubs, highlighting logistics as a key equity constraint.