环境税政策下企业副产品协同决策研究

Production Decision of Manufacturer Considering By-product Synergy under Environmental Tax Policy

副产品协同是实现废弃物资源化利用的有效策略。本文基于政府的环境税政策,在企业采取、不采取副产品协同策略两种情形下,构建了政府与企业的博弈模型,讨论了政府最优税收设置和企业的生产决策问题,并比较了两种情形下的社会福利、环境效益和企业利润。研究表明:环境税会降低主产品产量以减少废弃物排放,同时增加副产品产量以促进废弃物的资源化利用;企业选择副产品协同策略可以提升社会福利,改善环境效益;在环境税政策下,副产品协同并不总是企业的最优策略选择;存在副产品投资成本系数的阈值,当系数小于该值时,副产品协同策略总能提升企业的利润,当系数大于该值时,企业的策略选择与废弃物的环境损害成本有关。

With the increasing pressure of resources shortage and environmental pollution,the government and manufacturer are seeking measures to promote the sustainable development of economy.By-product synergy(BPS)is an effective way to achieve waste utilization and resources conservation.To encourage manufacturer to consider resource utilization of waste,environmental tax policy is designed by government.It aims to investigate the optimal production decision of manufacturer with the consideration of BPS and environmental tax policy in this paper.A manufacturer is considered that produces prime product A and generates a certain proportion of waste which may cause environment pollution.The government levies environmental tax on manufacturer to improve waste treatment and reduce environmental impact.Besides discharging waste into environment and paying the tax to the government,the manufacturer can also invest to implement BPS and convert waste into by-product B which will be sold in another market.Considering two cases:the manufacturer does not implement BPS,the manufacturer implements BPS,Stackelberg game models of the government and the manufacturer are established.As the leader,the government makes decision on tax rate to maximize social welfare,while the manufacturer decides the quantity of the prime product and by-product.The backward induction method is applied to get the equilibrium solutions of the models.By comparing the two cases,the impact of by-product synergy strategy of manufacturer on social welfare and environmental benefits is analyzed.Whether the manufacturer would choose BPS strategy under environmental tax policy is also discussed.The results show that the environmental tax will reduce the waste emissions of manufacturer by reducing the output of prime product and accelerate the utilization of waste by increasing the output of by-product.When the environmental damage cost is relatively small,the government will be inclined to set higher tax to stimulate manufacturer to implement BPS.When the manufacturer chooses BPS strategy,the social welfare and environmental benefits are better than that without BPS.So,BPS strategy is always conducive to environmental protection and social welfare improvement.The tax policy may affect the choice of manufacturer about BPS strategy.There is a threshold value of investment cost coefficient.When the investment cost coefficient is less than this value,the profit of manufacturer will be always improved if BPS strategy is chosen.On the contrary,when the coefficient is greater than this value,BPS strategy may not be chosen because the profit of the manufacturer who chooses BPS strategy may decrease when the environmental damage cost of waste is moderate.