Economic feasibility of subsidy-free rooftop PV enabled by green electricity certificates

Amidst the recent subsidy retrenchment for solar PV, environmental attribute revenue presents a promising mechanism to support the industry's transition to a subsidy-free era. This is the first study that develops a multi-regional economic feasibility assessment model for rooftop PV incorporating green electricity certificates (GEC) and quantitatively compares the profitability enhancement potential of GEC versus the emissions trading system (ETS) for rooftop PV. The results indicate that, in the absence of subsidies, all provinces can achieve a positive net present value (NPV), and 93.55 % attain an internal rate of return (IRR) exceeding the 6 % discount rate and a discounted payback period (DPBP) within the 20-year lifespan. Tibet, Beijing, and Heilongjiang exhibit the strongest economic viability, whereas Guizhou, Chongqing, and Yunnan demonstrate the lowest profitability. Northern and northwestern provinces have significantly lower levelized costs of electricity (LCOE) compared to southern regions. GEC income contributes between 4.80 % and 81.31 % to the total NPV. Monte Carlo sensitivity analysis reveals that the self-consumption ratio, surplus electricity feed-in price, discount rate, and initial investment cost are key variables driving substantial variations in economic feasibility. Comparative analysis shows that ETS outperforms GEC in enhancing rooftop PV profitability in most regions, except for Qinghai, Sichuan, Yunnan, and Tibet. Based on these findings, the study proposes regionally differentiated policy recommendations to promote future rooftop PV development in the post-subsidy era.