基于混合生命周期评价的不同坝型温室气体排放对比分析

为了研究不同坝型对环境造成的影响,采用混合生命周期评价方法定量分析并比较同规模的重力坝和堆石坝水电枢纽布置在全生命周期内的温室气体排放.研究基于糯扎渡工程实例,生命周期考虑材料设备生产阶段、运输阶段、施工阶段和运行维护阶段.结果表明:重力坝方案和堆石坝方案生命周期温室气体排放量分别为1145.49×104和815.85×104t(以CO2当量计),重力坝比堆石坝多排放40.4%.其中,重力坝在生产、运输和运行阶段的碳足迹比堆石坝大,但堆石坝在施工阶段的碳足迹比重力坝大.运行阶段的温室气体排放量占全生命周期碳足迹的比例最大,其次是材料设备生产阶段、施工阶段和运输阶段.糯扎渡水电工程的碳排放因子明显低于火电碳排放因子,合理开展水电建设,是实现我国"十二五"规划碳减排目标的有效途径.

Comparative analysis of greenhouse gas emissions from different dam types based on the hybrid LCA

In order to explore the effects of different dam types on the environment, a hybrid life cycle assessment (hybrid-LCA) method is presented to analyze and compare the greenhouse gas (GHG) emissions for different hydropower project layouts with the same size throughout the whole life cycle. For this purpose, the Nuozhadu project with concrete gravity dam and rockfill dam schemes is selected as the example. The production stage, transportation stage, construction stage and operation and maintenance stage of the material and equipment are taken into consideration in the life cycle. The results show that the CO₂ emissions of gravity dam and rockfill dam are 1145.49×10⁴ t and 815.85×10⁴ t CO₂-eq, respectively. The gravity dam increases CO₂ emissions by approximately 40.4% as compared with the rockfill dam. The carbon footprints of the gravity dam in the production, transportation and operation stages are larger than that of the rockfill dam. However, the carbon footprints of the rockfill dam is smaller than that of the gravity dam in the construction stage. The operation stage is the greatest contributor to CO₂ emissions, followed by the production stage, the construction stage and the transportation stage. The carbon emission factor of Nuozhadu hydropower station is obviously lower than that of the coal-fired power plant. The reasonable development of hydropower is an effective way to achieve carbon emission reduction in the 12th Five-Year Plan.