產品碳、水足跡盤查案例探討-以橡膠產品為例

Abstract

近年來全球暖化問題日益嚴重，暖化現象造成的氣候變遷亦對水循環系統產生衝擊，為管理溫室氣體排放及水資源耗用問題，「碳足跡」及「水足跡」指標提供產業量化溫室氣體排放與水資源耗用情形的重要方法。綜觀，目前國內產品碳、水足跡盤查作業一般以單一產品、單一指標為評估標的，評估結果通常又因系統邊界之差異，造成同類產品數據間不具比較意義。本研究以橡膠產業為案例，選定聚丁二烯橡膠(PBR)、苯乙烯-丁二烯橡膠(SBR)及苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物(SEBS)等三產品為盤查標的；量化標準採用「ISO/TS 14067產品碳足跡量化與溝通要求」及「水足跡評估手冊」，以生命週期評估方法進行盤查作業；於相同盤查範疇與系統邊界的架構下，同時執行三項標的產品之碳、水足跡評估，可取得較豐富且具比較性的同類型產品數據，用以分析探討橡膠產品碳、水足跡的減量機會。 研究發現(一)標的產品碳、水足跡數據以SEBS最高、PBR次之、SBR最低。(二)標的產品碳、水足跡熱點均集中於製造階段之能資源消耗，其中又以燃料油項目衍生的碳、水足跡平均佔比較高。以研究產品為例，若以天然氣替代燃料油做為鍋爐燃料，平均可降低13.49%碳足跡與38.78%水足跡。(三)產品產能利用率為影響碳、水足跡之關鍵要素，迴歸分析顯示產能利用率與碳、水足跡量呈負線性關係；當產量越大時，該產品所產生之碳、水足跡量越低。(四)廢水排放若為納管處理，灰水計算應採用工業區污水處理廠放流之污染負荷為計算基準，並使用水量作為分配原則將污染負荷分配至標的產品生產廠區，以符合本土化之情境。

In the recent years, the global warming issue is an increasingly serious problem. Warming phenomenon not only caused the climate change but also impacted on water resources and circulatory system. In order to manage the problems of greenhouse gas emission and water resources consumption, carbon footprint (CFP) and water footprint (WFP) assessment indicator is the method provides industry to quantify these problems. In Taiwan, CFP/WFP inventory system is currently evaluated by single product and single-index indicator. However, due to different system boundaries, the data brings meaningless by evaluating single product. This study mainly focused on single industry--rubber industry, including polybutadiene rubber (PBR), styrene butadiene rubber (SBR) and styrene-ethylene/butylene-styrene (SEBS) as inventory targets. Standard quantification adopts “ISO/TS 14067 Greenhouse gases -- Carbon footprint of products -- Requirements and guidelines for quantification and communication” and “Water footprint assessment manual”, and completes the inventory procedure by the method of life cycle assessment. Under the structure of same type inventory category and system boundary, we can get a relatively abundant data when evaluating these three targets simultaneously by CFP/ WFP assessment which could analyze the possibility to reduce CFP/WFP assessment indicator on rubber products. This study found that (a) The CFP/WFP assessment indicator shows that SEBS is the highest, PBR is intermediate, and SBR is the lowest; (B) The hotspot of CFP/WFP centralized in the energy resource consumption during manufacturing phase, and compared with CFP/WFP derived from other the energy resources, those derived from the fuel oil occupies the highest proportion. In this study, we found that if fuel oil is replaced with the natural gas as boiler fuel, 13.49% of CFP and 38.78% of WFP will be reduced on average. (C) Capacity utilization is the key factor on CFP/WFP. Our regression analysis shows negative linear correlations between capacity utilization and CFP/WFP. When capacity utilization climbed up, the CFP/WFP decreases. (D) If some plant’s wastewater effluent is all treated by wastewater treatment plant in industrial park, the calculation of its grey water should be based on pollution loading of the wastewater treatment plant in the industrial park, and water quantity should be used as allocation principles to allocate pollution loading to the production plant of the target product in order to match the localized scenario.