Abstract: Due to the complexity of the cooperation mode, the key to ensuring successful implementation of a PPP project is the reasonable allocation of risk and profit between the private entity and the government. Considering the earning uncertainty during operation period, the flexible concession mode is more effective than the fixed concession mode in terms of solving the problem of regulation failure, and the forecasting error of demand is the key factor influencing the accuracy of forecasting revenue. To reduce negotiation costs and ensure the dynamic equilibrium of risks and benefits, this paper proposes a concession period-price adjustment model taking into account demand uncertainty based on the credibility theory of fuzzy mathematics. In this model, the forecasting error of demand is regarded as fuzzy variable, and the strategy of symmetric adjustment of the concession period and price is regarded as the decision variable; the expected return error under different combination, and the credibility distribution under positive earnings expectation can be derived through fuzzy simulation, so we can achieve feasible combinations. According to the case study, the model can effectively address the estimation influence on concession period incurred by demand uncertainty, provide a more scientific decision-making basis for determining reasonable combination of concession period and price adjustment by considering forecasting error of demand neglected in previous studies.

Key words: Public-Private Partnership, credibility theory, concession period, price, fuzzy simulation

摘要： 需求预测误差是影响PPP项目收益预测准确性的主要因素。为减少谈判争议,确保风险和收益的动态均衡,本文基于模糊数学可信性理论,构建了考虑需求不确定的特许期-价格联合调整模型。将项目运营期间的需求预测误差作为模糊变量,将运营期内特许期和价格的联合调整策略作为决策变量,通过模糊模拟求解出不同特许期和价格调整组合下的期望收益误差以及正收益预期下的可信性,进而得到特许期和价格的联合调整策略可行解集。并将该模型应用于某污水项目中,结果表明,该模型能够有效地解决需求不确定性风险对特许期测算影响的问题,弥补了目前PPP项目特许期和价格调整决策研究中未考虑需求预测误差的不足,对PPP项目特许期和价格的调整决策有着重要的参考意义。

关键词: 公私合作, 可信性理论, 弹性特许期, 价格调整, 模糊模拟