Market power in emissions trading has been extensively investigated because emerging markets for tradable emissions permits, such as the European Union's Emissions Trading Scheme (ETS), can be dominated by relatively few large sellers or buyers. Previous studies on market power in emissions trading have assumed the existence of a subset of competitive players. However, a key feature of emissions trading markets is that emissions permits are often traded by a small number of large sellers and buyers. Using a laboratory experiment, our objective in this paper is to test the performance of an emissions trading market utilizing a double auction in a bilateral oligopoly. Our results suggest that the theoretical bilateral oligopoly models can better describe market outcomes of emissions trading. The effects of the slope of the marginal abatement cost function on market power in laboratory experiments are found to be consistent with those predicted by the theoretical bilateral oligopoly model. How market power is exercised depends on the curvature of the abatement cost function. If the marginal abatement cost function of buyers (sellers) is less steep than that of sellers (buyers), the price of permits is lower (higher) than that under perfect competition. This is because the market power of buyers (sellers) exceeds that of sellers (buyers). The price of permits is close to the perfect competitive price when all traders have the sameslope of the marginal abatement cost function.

排放交易的市场力量已得到广泛研究，因为可交易的排放许可证的新兴市场，例如欧盟的排放交易计划（ETS），可以由相对较少的大型卖方或买方主导。先前有关排放权交易中市场支配力的研究假设存在竞争参与者。但是，排放交易市场的一个关键特征是排放许可证通常由少数大型卖方和买方进行交易。通过实验室实验，我们的目标是通过双边寡头垄断的双重拍卖来测试排放交易市场的表现。我们的结果表明，理论上的双边寡头垄断模型可以更好地描述排放权交易的市场结果。在实验室实验中，边际减排成本函数的斜率对市场支配力的影响被发现与理论上的双边寡头垄断模型所预测的一致。如何行使市场支配力取决于减排成本函数的曲率。如果买主（卖方）的边际减排成本函数不如卖主（买方）的边际减排成本函数陡峭，则许可证的价格要比完全竞争时的价格要低（更高）。这是因为买方（卖方）的市场力量超过卖方（买方）的市场力量。当所有贸易商的边际减排成本函数具有相同的斜率时，许可证的价格接近完美的竞争价格。如何行使市场支配力取决于减排成本函数的曲率。如果买主（卖方）的边际减排成本函数不如卖主（买方）的边际减排成本函数陡峭，则许可证的价格要比完全竞争时的价格要低（更高）。这是因为买方（卖方）的市场力量超过卖方（买方）的市场力量。当所有贸易商的边际减排成本函数具有相同的斜率时，许可证的价格接近完美的竞争价格。如何行使市场支配力取决于减排成本函数的曲率。如果买主（卖方）的边际减排成本函数不如卖主（买方）的边际减排成本函数陡峭，则许可证的价格要比完全竞争时的价格要低（更高）。这是因为买方（卖方）的市场力量超过卖方（买方）的市场力量。当所有贸易商的边际减排成本函数具有相同的斜率时，许可证的价格接近完美的竞争价格。