资源循环助推碳中和的路径

 再生资源的循环利用是实现可持续发展和碳中和目标的强大支撑。为了定量评估再生资源循环利用的碳减排潜力,基于物质流分析和生命周期评价方法,核算了大宗物质资源,主要包括水泥、沙子、碎石、砖块、石灰、玻璃、橡胶、木材、塑料、沥青、钢铁、铝和铜等的循环利用潜力,特别对“高耗能、高排放、高产量”的钢铁和水泥行业的碳减排路径和碳中和潜力进行了梳理和分析。测算结果表明,大宗物质资源的需求量将在2022—2025年达峰后持续减少,2030年后物质资源报废量将逐年增加,并于2060年达到约54.6亿t/a,建筑垃圾的比例高达90%且集中在东南沿海省份; 2019—2060年,大宗物质资源需求量的减少导致了碳排放的持续降低,若协同资源高效循环策略,2060年碳排放量将下降至4.3亿t/a,比2018年排放水平低77%。其中,废金属尤其是废钢铁的循环利用碳减排潜力最大,若在2060年将废钢铁的循环利用率提高至90%以上,碳减排量将达到4.4亿t/a,比2018年碳排放量降低90%。相比之下,水泥由于回收处理技术和产品回收价值的限制,仅能通过提高资源使用效率和延长产品使用寿命等策略达到碳减排效果。最后,阐述了“十四五”时期作为推动再生资源循环利用的关键期和窗口期需要部署的资源循环政策、模式和技术等,为助力碳中和目标的实现提供重要支撑。

Reducing carbon emissions by recycling bulk materials: Potentials and pathways

The recycling of renewable resources is a feasible, cost-controllable, replicable and popularizable carbon emission reduction scheme, which is a strong support for achieving sustainable development and carbon neutrality. In view of the lack of quantitative assessment of carbon emission reduction potential of renewable resources recycling, this study evaluates the recycling potential of bulk material resources, including cement, sand, gravel, brick, lime, glass, rubber, wood, plastics, asphalt, steel, aluminum and copper. In particular, the carbon emission reduction path and carbon neutralization potential of the steel and cement industries with "high energy consumption, high emission and high output" were sorted out and quantitatively assessed. The calculation results show that the demand for bulk material resources will continue to decrease after reaching the peak around 2025, and the amount of scrapped material resources will increase after 2030. The amount of scrapped material resources will reach about 5.46 billion tons per year in 2060, and the proportion of construction waste will be as high as 90% and concentrated in the southeastern coastal provinces. From 2019 to 2060, the reduction of demand for bulk material resources has led to the continuous reduction of carbon emissions. If the circular economy strategies are coordinated, the CO2 emissions in 2060 will be reduced to 430 million tons per year, 77% lower than the emission level in 2018. Among them, the recycling of scrap metals, especially scrap iron and steel, has the greatest potential for CO2 emission reduction. If the recycling rate of scrap iron and steel is increased to more than 90% in 2060, the carbon emissions of the iron and steel industry in 2018 will be reduced by 90%, and the carbon emissions will be reduced by 440 million tons. In contrast, due to the limitation of recycling technology and product recycling value, cement production can only achieve CO2 emission reduction by improving resource efficiency and prolonging product service life. Finally, this study describes the resource recycling policies, models and technologies that need to be deployed during the "14th Five-Year Plan" period as the key period and window period to promote the recycling of renewable resources. Our study provides important support for the realization of carbon neutrality goals.