禽肉產品碳排放檢視及改善措施之研究－以白肉雞屠宰場為例

Abstract

屠宰是肉製品生產的重要過程，是碳排放的關鍵來源之一，瞭解屠宰流程的碳排熱點，能作為改善產品碳足跡的依據。關於碳足跡管理的國際標準中有ISO 14064和ISO 14067，ISO 14064是用於指導組織量化和報告其溫室氣體排放，這包括直接和間接的排放，並提供了一個框架，幫助組織確定和實施溫室氣體減排目標，這項標準有助於企業評估其對氣候變化的影響，並制定相應的減排策略；而ISO 14067則是一個指導企業評估產品碳足跡的標準，它提供了一套方法，幫助企業量化其產品的碳排放量，並通過採取相應的減排措施來減少這些排放，這有助於企業更好地了解其產品對氣候變化的貢獻，並促使它們採取更環保的生產方式。此兩項標準的實施皆有助於推動企業向更永續性的發展方向轉變，減少對環境的負面影響。因糧食系統於全球溫室氣體排放佔比近1/3，其中肉品生產更視為大宗項目，隨著全世界人口不斷的上升，可以預期對於肉品的需求及消費將大幅增加，進而導致嚴重的環境衝擊，因此改變肉品生產方式以減少環境衝擊是重要課題。本研究以臺灣2家（皆為臺灣前10大家禽電宰廠）具有於三個屠後檢查站之白肉雞屠宰場為調查標的，盤查其於2021年度屠宰白肉雞所排放的總碳量，並對各場屠程實狀分析熱點及排碳佔比，同時提出可供未來改善的建議。主要研究方向有三：（i）單位碳足跡分析；（ii）各階段排碳量分析；（iii）各項目排放量分析。結果如下：（i）A屠宰場年屠宰量為18,246,909隻（屠體總重40,136公噸），總排放量為7,231.190噸CO2e，平均屠宰每公斤毛雞之單位碳足跡為0.180 kgCO2e/kg，平均屠宰每隻毛雞之單位碳足跡為0.396 kgCO2e/隻；B屠宰場年屠宰量為20,835,775隻（屠體總重43,547公噸），總排放量為5,242.072噸CO2e，平均屠宰每公斤毛雞之單位碳足跡為0.120 kgCO2e/kg，平均屠宰每隻毛雞之單位碳足跡為0.252 kgCO2e/隻；（ii）屠宰分切階段A屠宰場排碳佔比達93.36%，B屠宰場達77.70%；廢棄物處置階段A屠宰場占6.61%，B屠宰場占22.16%；廢棄物運輸階段2家屠宰場排碳佔比皆小於1%；（iii）A屠宰場排放熱點以電力為主要排碳貢獻占71.76%，次之為製冷設備冷媒逸散占11.76%，而鍋爐使用之天然氣占6.97%及廢水處理占5.09%；B屠宰場排放熱點電力排碳貢獻占62.53%，次之為廢水處理占21.63%，而鍋爐使用之液化石油氣占8.59%及製冷設備冷媒占6.01%。比較國外相關調查，臺灣此形式之白肉雞屠宰排碳單位量較高。進一步分析兩場的明顯差異包括製冷設備的設置及熱能化石燃料項目選擇，致使A場在電力、冷媒逸散及熱能使用項目的排碳量偏高；此外改善廢污水處理模式（例如B場加設甲烷收集設備）也將有效降低排放總量。因應未來的碳權管理，設備升級、改善流程與效率及再生能源利用都是必要措施，屠宰產業宜儘早針對個別場區進行碳盤查，瞭解個別場域的碳排熱點，以規劃未來減碳作為。

Slaughtering is an important process in the production of meat products and one of the key sources of carbon emissions. Understanding the carbon emission hotspots in the slaughtering process can be used as a basis for improving the carbon footprint of products. The international standards related to carbon footprint management include ISO 14064 and ISO 14067. ISO 14064 is used to guide organizations in quantifying and reporting their greenhouse gas emissions, including both direct and indirect emissions. It provides a framework to assist organizations in identifying and implementing greenhouse gas reduction targets. This standard helps businesses assess their impact on climate change and develop corresponding emission reduction strategies; ISO 14067, on the other hand, is a standard guiding businesses in assessing the carbon footprint of their products. It provides a methodology to help companies quantify the carbon emissions of their products and reduce these emissions through corresponding mitigation measures. This aids businesses in better understanding the contribution of their products to climate change and encourages them to adopt more environmentally friendly production methods. The implementation of these two standards helps drive businesses towards more sustainable development, reducing their negative impact on the environment. Because the food system accounts for nearly 1/3 of global greenhouse gas emissions, and meat production is considered a bulk item, as the world's population continues to rise, it can be expected that the demand and consumption of meat will increase significantly, leading to serious environmental impact, so changing meat production methods to reduce environmental impact is an important issue. This study takes two broiler slaughterhouses in Taiwan (both of which are among the top 10 largest poultry slaughterhouses in Taiwan) with three post mortem inspection stations as the subject of investigation, and examines the total carbon emissions emitted by slaughtering broilers in 2021. It also analyzes hot spots and carbon emission proportions of each slaughtering process, and puts forward suggestions for future improvements. There are three main research directions: (i) unit carbon footprint analysis; (ii) analysis of carbon emissions at each stage; (iii) analysis of emissions from each item. The results are as follows: (i) The annual slaughtering quantity of SA is 18,246,909 birds (the total carcass weight is 40,136 metric tons), the total emissions are 7,231.190 tons of CO2e, the average unit carbon footprint per kilogram of slaughtered chickens is 0.180 kgCO2e/kg, the average unit carbon footprint of each slaughtered chicken is 0.396 kgCO2e/bird; the annual slaughtering quantity of SB is 20,835,775 birds (total carcass weight 43,547 metric tons), the total emissions are 5,242.072 tons of CO2e, the average unit carbon footprint of each kilogram of slaughtered chickens is 0.120 kgCO2e/kg, and the average unit carbon footprint of each slaughtered chicken is 0.252 kgCO2e/bird; (ii) the carbon emission ratio of SA in the slaughtering and cutting stage is 93.36%, and that of SB is 77.70%; waste disposal stage in the SA accounts for 6.61%, and in the SB accounts for 22.16%; in the waste transportation stage, the carbon emissions of the two slaughterhouses are both less than 1%; (iii) At SA, the primary carbon emission hotspot is electricity, accounting for 71.76% of emissions, followed by refrigerant leakage from refrigeration equipment at 11.76%, with natural gas used in boilers contributing 6.97%, and wastewater treatment contributing 5.09%. At SB, the main carbon emission hotspot is electricity, contributing 62.53% of emissions, followed by wastewater treatment at 21.63%, with liquefied petroleum gas used in boilers contributing 8.59%, and refrigerant leakage from refrigeration equipment contributing 6.01%. Comparing with other countries, the carbon emissions per unit of broiler slaughtered from this style in Taiwan are higher. Further analysis reveals significant differences between SA and SB, including the refrigeration equipment and the usage of fossil fuel for heating, resulting in higher carbon emissions in SA in electricity, refrigerant leakage, and energy for heat. Additionally, optimization the wastewater treatment mode (such as installing methane collection facility in SB) would also effectively reduce the total emissions. In response to future carbon credit management, upgrading equipment, improving efficiency, and choosing renewable energy are necessary. The slaughter industry should conduct carbon audits for individual sites early to understand the carbon hotspots of each location, in order to plan future carbon reduction measures.