Green signal addresses the financing dilemmas in port development

With increasing global trade demands and the digital and green transformation of ports, the financing dilemma has emerged as a critical constraint on port development. To address the issue of information asymmetry between ports and investors, this paper proposes green port construction with the shore power berth installation rate as a core indicator as a signaling mechanism, constructing a dynamic Bayesian game model to analyze the strategic interactions and equilibrium conditions between ports and investors. The research demonstrates that when the shore power berth installation rate falls within a reasonable range (i.e., the cost of green construction for high-utilization ports is lower than their digitalization returns, while the cost exceeds returns for low-utilization ports), a separating equilibrium can be achieved—efficient ports signal their high quality through green construction to attract investment, while inefficient ports abstain from such initiatives. Numerical simulations, based on data from Hebei Port Group, validate the effectiveness of this mechanism and highlight that excessively high shore power installation standards can lead to a pooling equilibrium, resulting in investor refusal to finance. The numerical simulation also shows the speed at which the game tends toward equilibrium under different conditions. The stronger the profitability of the port after receiving investment, and the greater the probability that investors adopt a strategy to recognize green signals at the initial stage of the game, the faster the game tends to move towards a separating equilibrium.