Renewable energy investment and electricity procurement with ambiguity aversion under carbon emission trading and tradable green certificate policies

Under the policy frameworks of carbon emission trading (CET) and tradable green certificates (TGC), this study investigates power supply chain decision-making under multiple sources of uncertainty. An ambiguity-averse distributionally robust optimization approach is embedded into a dynamic game framework to characterize equilibrium outcomes under CET, TGC, and mixed policy scenarios. The model examines renewable capacity investment and electricity procurement decisions, and evaluates the emission reduction effects and environmental value of different policy instruments through numerical experiments. The results show that CET and TGC policies exhibit complementary investment incentives under uncertainty. Carbon and green certificate prices generate dual effects through their expected levels and volatility: higher price levels strengthen investment incentives, whereas increased volatility weakens them under ambiguity-averse behavior. On the demand side, CET helps sustain overall electricity consumption growth, while TGC is more effective in steering the consumption structure toward renewable electricity. Moreover, when the retailer shifts from ambiguity-neutral to ambiguity-averse behavior, electricity demand increases, leading to higher equilibrium profits for the generator. These findings provide policy-relevant insights for optimizing policy design under uncertainty and risk-averse behavior.