碳限额与交易机制下供应链运作优化研究

Study on Supply Chain Operations Optimizationunder Carbon Cap and Trade Mechanism

碳限额与交易机制是一种利用市场手段来控制碳排放总量的有力措施,受到了世界各国的高度关注。本文针对碳限额与交易机制下供应链运作优化问题,考虑由供应商和采购商构成的两级供应链系统,建立了碳限额与交易机制下的供应链联合经济批量(JELS)模型,求解出了最优生产批量和最优订购批量。通过与传统的联合经济批量模型比较,论证了碳限额与交易机制的有效性,解析和数值算例分析了碳限额与交易机制下碳价和碳限额等因素对供应链决策、碳排放总量和总成本的影响,从解析结论和数值算例分析中得到了一些碳限额与交易机制下供应链运作管理的新见解。

Global warming caused by carbon emissionsposes a serious threat to globalecosystems and human survival. How to reduce carbon emissions effectively has become a worldwide concern. Carbon cap and trade mechanism are effective measures to regulate carbon emissions by market means. These measures areregarded as one of the most effective market mechanisms. EU emissions trading system （EU ETS） is one of the most influential carbon emission trading market in the world. In order to cope with regulation policyon carbon emissions, firms need to take carbon emissions intoconsideration in their operations. Some scholars have studied the production operation of a single firm at micro level, includingoperations optimization models with carbon emission constraints and the analysis of the influence of carbon emissions factors on firm＇s operationsoptimization. However, firms are not isolated. If only considering carbon emissions from the perspective of a single firm, we would overlook the impact ofthe interactions among multiple firms onthe supply chain system. In addition, the carbon footprint of other supply chain members increaseswith thearnounts of their transportations and inventories.Therefore, it is necessary to study the optimization of supply chain operations under carbon cap and trade mechanism from the perspective of supply chain management. Moreover, the study tries tooptimize operational costs and carbon footprint as a whole. This paper focuses onthe optimization of supply chain operations under carbon cap and trade mechanism. Based onthe two-level supply chain that consists of a single vendor and a single buyer, this paper proposes a modified joint economic lot sizing （JELS） model under carbon cap and trademechanism, and analyze how to optimize operational costs and carbon emissions. Secondly, this study compared with the classic JELS model, and discussed the impact of carbon cap and trade, carbon price and carbon cap on supply chain decisionsforcarbon emissions and operational costs. Some managerial insights of supply chain operations under carbon cap and trade mechanism are provided based onthe analysisresults. The study shows that the optimal value of production quantity or order quantity of the modified JELS model is between that of classical JELS model and that of the model which only considers minimizing carbon emissions. The carbon cap and trade mechanism can induce the supply chain to reduce carbon emissions, which implies the effectiveness of carbon cap and trade mechanism. Especially, carbon emission reduction does not necessarily lead tuthe increase of operational costs in the supply chain. The conditions under which supply chain may reduce carbon emissions andoperational costs simultaneouslyare analyzed, There exists a threshold of carbon cap which determines whether to trade carbon emission permits or not in the supply chain. The operational costs of a supply chain are bound to increase when a supply chain buys carbon emission permits from market. If carbon price is assumed fixed, the carbon cap of a single supply chain has no effect on order quantity, production quantity and operational costs of the supply chain system, This conclusion does not mean the invalidation of carbon cap and trade mechanism. On the contrary, it emphasizes the necessity of reasonable carbon pricing when adopting carbon cap policy.Furthermore, if the carbon cap decreases （or increases）, the supply chain has to trade more （or less） carbon emission permits, and leads to increase （or decrease） operational costs. The above results are useful for a supply chain to make right decisions under carbon cap and trade mechanism. Finally, the derived propositions and managerial insights are illustrated by numerical examples.