基于混合生命周期评价的小型灌溉泵站碳排放核算方法研究

STUDY ON A CARBON EMISSION METHOD FOR SMALL IRRIGATION PUMPING STATIONS BASED ON HYBRID LIFE CYCLE ASSESSMENT THEORY

小型灌溉泵站是农田灌溉的重要基础设施,单座规模较小但数量庞大,从“双碳”角度对其开展全生命周期的碳排放核算分析对实现其可持续发展和促进高效供水具有重要意义。基于碳足迹理论,采用混合生命周期分析法,将灌溉泵站全生命周期分为材料设备生产、材料设备运输、建设施工、运行维护和拆除报废5个阶段,分析了灌溉泵站在建设、运行、管理整个过程中的碳排放规律,构建了小型灌溉泵站碳排放模型核算方法,包括核算原理、研究思路、计算流程和核算公式等。选择了6处不同地区小型灌溉泵站开展了碳排放核算方法的实例分析,结果显示:6处灌溉泵站的碳排放总量分别为402.87,34.30,849.37,140.93,1645.56,312.89 t CO_(2)e,年单位灌溉面积的碳排放系数分别为331,147,681,144,202,126 kg CO_(2)e/(hm^(2)·a);各个阶段的碳排放量具有较大差异,总体来看运行维护阶段(62.57%)和材料设备生产阶段(26.64%)排放量最大,建设施工阶段(5.32%)、拆除报废阶段(4.78%)、材料设备运阶段输(0.69%)的排放量相对较小;碳排放受地域提水灌溉特点、泵站规模、灌溉面积、灌溉作物及其用水量、抽水扬程、供电方式等因素影响,表现出一定的差异性;供电方式表现出较大的差异性,相比之下单独太阳能光伏供电比统一电网供电的碳排放量更低,且前者是在建设施工阶段(56.67%)排放量最大,其次是运行维护阶段(19.04%);参数的不确定性分析显示,构筑物寿命年限取值对碳排放核算的敏感性最强,在测算时应结合实际和规范综合考虑进行合理取值;针对不同类型灌溉泵站在不同阶段的碳排放特点提出了针对性的减碳措施。研究结果可为科学核算灌溉泵站碳足迹、建设绿色节约型水利基础设施、促进农村水利低碳发展提供技术参考。

As an important infrastructure for the irrigation of farmland in plain regions,small irrigation pumping stations are small in scale but large in number.This paper analyzes the full life cycle carbon emission accounting of the irrigation pumping stations from the perspective of‘dual carbon',which is of great significance for achieving its sustainable development and promoting efficient of water extraction.Based on the carbon footprint theory,this paper adopts a hybrid life cycle assessment method,and divides the whole life cycle of an irrigation pumping station into five stages:material and equipment production,material and equipment transportation,construction,operation and maintenance,and demolition.This study analyzes the carbon emission law of irrigation pumping stations in the whole process of construction,operation,and management,and establishes a carbon emission model accounting method,including the accounting principle,research ideas,calculation process,and the accounting formula,etc.The results show that the total carbon emissions of the six irrigation pumping stations are 402.87,34.30,849.37,140.93,1645.56,312.89 t CO_(2)e,and the annual carbon emission coefficients per unit of irrigated area are 331,147,681,144,202,126 kg CO_(2)e/(hm^(2)·a)),respectively;the carbon emissions of each stage vary greatly,with the largest emissions coming from the operation and maintenance phase(62.57%)and the material and equipment production phase(26.64%),while emissions from the construction phase(5.32%),the dismantling and scrapping phase(4.78%)and the material and equipment transportation phase(0.69%)are relatively smaller.Carbon emissions are influenced by the characteristics of irrigation,pumping station size,irrigation area,irrigated crops,and their water consumption,pumping head,power supply method,etc.,and show some variability;the power supply method shows greater variability,with solar PV alone showing lower carbon emissions than uniform grid power supply in comparison,and the former type has the highest emissions during the construction phase(56.67%),followed by the operation and maintenance phase(19.04%).The uncertainty analysis of the parameters shows that the value of the lifetime of the structure is the most sensitive to the carbon emission accounting,and should be considered in the measurement of the actual and comprehensive consideration of the norms to make reasonable values.This has led to targeted carbon reduction measures for different types of irrigation pumping stations at different stages of their carbon emission characteristics.The research results provide a technical reference for scientific accounting of the carbon footprint of irrigation pumping stations,building green and economical water infrastructure,and promoting low-carbon development in rural water resources.