绿色PPP项目组合的最优契约:经济与环境效应的福利视角  

The Optimal Contract for Green PPP Project Portfolios:A Welfare Perspective for Economic and Environmental Effects

作　　者：魏晓云[1] 韩立岩[2] WEI Xiaoyun;HAN Liyan(School of Statistics,Capital University of Economics and Business;School of Economics and Management,Beihang University)

机构地区：[1]首都经济贸易大学统计学院,北京100070 [2]北京航空航天大学经济管理学院,北京100191

出　　处：《金融研究》2022年第3期60-78,共19页Journal of Financial Research

基　　金：国家自然科学基金(71673020,71690244,71850007)的资助。

摘　　要：绿色PPP搭配高收益项目的激励方式是吸引社会资本参与环境治理的举措之一。本文基于经济与环境的双重福利效应,从理论上研究了该激励方式的契约设计问题,阐释了博弈均衡的存在性以及最优特许期的形成逻辑和关键决定因素。研究表明:第一,绿色PPP搭配高收益项目能够提高企业利润,激发社会资本参与环境治理来应对环境风险。第二,政企双方博弈决策模式决定了契约能否订立。如果独立决策,使企业利润最大的特许期也能够带来最高的环境效益,但此时博弈结果展现为“刀刃上的均衡”,契约难以建立;如果合作博弈,双方最优特许期选择达成一致,契约得以订立,政府向企业让渡经济利润而收获环境效益,最终实现经济与环境福利的双赢。第三,绿色PPP搭配高收益项目优于传统政府补贴的激励方式,在收获同等环境效益的基础上,能够带动社会总福利的提升。研究结论为绿色PPP搭配高收益项目激励方式的推广实施、从而助力实现碳达峰和碳中和战略目标提供了契约设计理论依据和相关框架。Green finance serves green investment,which serves the green economy.In practice,there is a huge demand for funds to develop green finance and promote environmental protection.In addition,it is unsustainable to rely solely on government financial support.Therefore,an important solution for this problem is public-private partnerships(PPP),in which the government and enterprises work together.However,enterprises are not enthusiastic participants of pollution prevention,green,and low-carbon PPP projects because they generally experience problems such as high investment thresholds,competition homogeneity,and high market risk.Although the direction of the new incentive method is clear,relying only on the traditional PPP contract framework is insufficient to manage the complex problems that arise when managing project portfolios.Thus,the contract model for traditional single-commercial PPP projects cannot be directly adopted.The key issues involved in the green PPP project portfolio are as follows:What elements must be considered when concluding the contract?What coordination mechanism must be selected to ensure that the contract is signed?Is there an optimal concession period for green PPP projects?Is the green PPP project portfolio better than the traditional incentive mechanisms of direct government subsidies?Exploring these issues will provide a good theoretical basis and technical support for the promotion and implementation of the combination of green PPP and high-yield projects.This paper uses the net present value method to propose a decision-making model for the optimal concession period of green PPP project portfolios based on the win-win goal of economic and environmental benefits.Our model differs from those of the literature in three dimensions.First,we introduce environmental benefits and extend the optimal concession period model for a single PPP project to the green PPP project portfolio.The goals of combining green PPP and high-yield projects include social welfare,environmental benefits,consumer surpl

关 键 词：绿色PPP项目 公私合作制 最优特许期 绿色金融 环境风险 

分 类 号：F283[经济管理—国民经济] F832[环境科学与工程—环境科学] X22