中文摘要
中国于2021年启动了全国性的基于强度的碳市场。该市场覆盖全球最大的二氧化碳排放国，其履约取决于碳排放强度而非绝对上限。我们借鉴关于基于强度体系的理论文献，首次提供了关于早期采用者的实证证据。利用来自卫星影像的工厂层面数据和机器学习方法，我们发现，相对于低效率电厂，高效率电厂将发电量和二氧化碳排放量提高了约5%。由于中国的碳市场几乎监管所有燃煤电厂，我们聚焦于按电厂效率划分的差异化反应，未发现排放强度出现差异化下降的证据（尽管这些估计并不精确）。相对于没有碳市场的印度尼西亚和菲律宾的燃煤电厂，中国的高效率电厂同样增加了排放，而对其低效率电厂的估计较小且不显著。这一反应模式表明，高效率电厂的排放增加超过了来自低效率电厂的替代。凸显出对更高效中国电厂的生产刺激的是，高效率电厂下风向的空气质量相对于低效率电厂下风向有所恶化，损害了中国相对清洁地区的空气质量。为抑制中国的碳排放水平从而减缓气候变化，需要在现有体系内收紧基准，或采用一种不会同时激励电力生产的替代体系。
Abstract
China launched a nationwide, rate-based carbon market in 2021. Covering the world’s top C O 2 emitter, compliance depends on the intensity of carbon emissions rather than an absolute cap. We draw on the theoretical literature on rate-based systems to provide the first empirical evidence on an early adopter. Using plant-level data from satellite imagery and machine learning methods, we find that high-efficiency power plants increased electricity generation and C O 2 emissions by approximately 5% relative to low-efficiency plants. Because its carbon market regulates nearly all coal plants in China, we focus on the differential responses by plant efficiency, finding no evidence of a differential reduction in emission intensity (though these estimates are imprecise). Relative to coal plants in Indonesia and the Philippines, which had no carbon market, China’s high-efficiency plants also increased emissions, while the estimate for its low-efficiency plants is small and insignificant. This pattern of responses suggests that emission increases of high-efficiency plants exceeded substitution away from low-efficiency plants. Underscoring the production stimulus to more efficient Chinese plants, air quality worsened downwind of high-efficiency plants relative to low-efficiency plants, compromising air quality in relatively clean areas of China. To curb the level of China’s carbon emissions and thereby slow climate change, benchmarks need to be tightened within the existing system or an alternative system adopted that does not simultaneously incentivize electricity production.