Many e-commerce supply chains adopt dual channels (marketplace and reselling) to reach more consumers. Comparison between the two channels has been thoroughly conducted in the literature. However, in most cases, the two channels are adopted sequentially rather than simultaneously. Research on whether to add another channel to a current channel is deficient. This paper investigates the channel addition problem of a manufacturer who currently sells products through an online platform via either marketplace or reselling channel. Regional carbon cap-and-trade regulation is applied on the manufacturer. We explore the optimal decisions and compare the optimal decisions and the profits of the manufacturer before and after channel addition. First, in the single channel, the optimal production quantities are increasing in the region-cap. However, in the dual-channel case, they are decreasing in the region-cap when the competition intensity between the two channels is moderate. Second, it is found that when adding reselling channel to marketplace channel, the manufacturer's profit will always increase; when adding marketplace channel to reselling channel, the manufacturer's profit will decrease if the commission rate is low and the order-fulfillment cost is high. Finally, the manufacturer and the platform cannot be coordinated in either marketplace channel or reselling channel without contracts, but can be coordinated in the dual-channel structure if the commission rate is low.

许多电子商务供应链都采用双重渠道（市场和转售）来吸引更多的消费者。文献中已经对两种渠道进行了比较。但是，在大多数情况下，这两个通道是顺序而不是同时采用的。关于是否将另一个频道添加到当前频道的研究不足。本文研究了当前通过市场或转售渠道通过在线平台销售产品的制造商的渠道增加问题。制造商适用区域性碳限额和贸易规定。我们探索最佳决策，并比较最佳决策和制造商在添加渠道之前和之后的利润。首先，在单通道中，区域上限的最佳产量正在增加。然而，在双通道情况下，当两个通道之间的竞争强度适中时，它们在区域上限中减小。其次，发现在将转售渠道添加到市场渠道时，制造商的利润将始终增加。当将市场渠道添加到转售渠道时，如果佣金率低且订单执行成本高，则制造商的利润将减少。最后，制造商和平台无法在没有合同的市场渠道或转售渠道中进行协调，但如果佣金率较低，则可以在双渠道结构中进行协调。制造商的利润将永远增加；当将市场渠道添加到转售渠道时，如果佣金率低且订单执行成本高，则制造商的利润将减少。最后，在没有合同的情况下，制造商和平台无法在市场渠道或转售渠道中进行协调，但如果佣金率较低，则可以在双渠道结构中进行协调。制造商的利润将永远增加；当将市场渠道添加到转售渠道时，如果佣金率低且订单执行成本高，则制造商的利润将减少。最后，制造商和平台无法在没有合同的市场渠道或转售渠道中进行协调，但如果佣金率较低，则可以在双渠道结构中进行协调。