現行國際生物炭碳信用獲取技術與方法學於臺灣之適用性評估研究

Abstract

為實現 2050 年淨零排放目標，生物炭作為負碳技術之一，具有固碳減排、增強土壤碳匯，並可參與國際碳交易市場之經濟價值。本研究選用兩項國際現行方法學《VM0044 生物炭於土壤與非土壤應用之使用方法學》（VM0044: Biochar utilization in soil and non-soil applications）與《Puro.earth生物炭方法學》（Puro.earth Biochar Methodology）作為實驗方法架構，將其應用於臺灣農業廢棄物資源情境中，估算可達成的碳移除量與潛在經濟收益，以此來初步評估農業廢棄物生物炭碳信用獲取在臺灣之適用性。根據行政院農業部113年度農業廢棄物統計資料，稻殼與稻蒿約占臺灣農業廢棄物總量的77%（約185萬噸），顯示其具有高度資源化潛力。本研究假設以熱裂解技術將其轉化為生物炭，為評估臺灣農業廢棄物熱裂解轉化為生物炭之產量，根據不同方法學所規範之農業廢棄物最高可使用上限量，推估每年可利用稻殼稻蒿量約為84-117萬公噸。考量熱裂解設備每年處理數量上限，依各區稻殼與稻蒿產量比例，，本研究將全臺劃分為北、中、南、東四區，按比例配置熱裂解處理數量。將以上情境與參數進一步代入兩種國際方法學進行民國113年度潛在的稻殼、稻蒿生物炭生產量以及碳信用之推估。 根據模擬結果，VM0044專案於2025年可生產約28萬噸生物炭，每公噸的生物炭能夠移除1.26噸CO2，而Puro.earth專案可生產37萬噸生物炭，每公噸生物炭則能移除0.88噸CO2。根據生物炭碳交易市場價格之估計（每移除1 tCO2e），若依VM0044於2025年成功取得並售出約 23.8萬至 35.5萬個 VCUs，預期可產生約4,227萬至6,287萬美元（約新台幣12億至18億元）之收益；若依 Puro.earth Biochar Methodology取得約32.8萬個 CORCs，潛在收入則可達約5819萬美元（約新台幣17億元）。可見全台稻殼與稻蒿生物炭得出的碳信用具備可觀的經濟產值。但上述估算結果尚未扣除成本、手續費、風險準備金與其他交易支出，實際價格仍須視專案品質、匯率與市場行情而定。 生物炭生產雖具減碳與經濟潛力，仍涉及設置成本、能源消耗與污染風險，如重金屬與有機物逸散。目前本研究未進行相關評估，若欲推動碳信用專案，應納入完整成本結構與敏感度及不確定性分析，以確保其可行性與永續性。本研究結合臺灣農業廢棄物情境進行初步推估與方法學模擬，顯示生物炭具備應用與碳收益潛力，並具有碳封存與市場交易的實務參考價值，未來仍需更多在地實證驗證其成效。

To achieve the goal of net-zero emissions by 2050, biochar, which is recognized as a negative emission technology, offers the potential for carbon sequestration, greenhouse gas reduction, and soil carbon enhancement. Meanwhile, the carbon sequestrated by biochar can possess economic value through participation in international carbon markets. To achieve a preliminary assessment of the applicability of carbon credit acquisition from agricultural-waste-based biochar in Taiwan, this study estimated the potential carbon removal and economic benefits of biochar derived from agricultural waste in Taiwan. Two internationally recognized methodologies were adopted in this study, which are "VM0044: Biochar Utilization in Soil and Non-Soil Applications" and the "Puro.earth Biochar Methodology", as the analytical frameworks According to the statistics from the Ministry of Agriculture in 2024, rice husks and rice straw constitute approximately 77% of the total agricultural waste in Taiwan, equivalent to around 1.85 million metric tons. This indicates a substantial potential of agricultural waste for resource valorization such as production of biochar. In the calculation, this study premises an application of pyrolysis technology to convert these feedstocks into biochar. efer to the. Based on the maximum allowable usage limits stipulated by each methodology, there were 0.84 to 1.17 million metric tons of rice husks and straw can be utilized annually in 2024. Considering the processing capacity of pyrolysis systems and the regional distribution of feedstock supply, the study divides Taiwan into four zones (north, central, south, and east) and allocates feedstock accordingly. These data and assumptions are subsequently input into both international methodologies for carbon credit estimation. Simulation results indicate that, under the VM0044 methodology, approximately 280,000 metric tons of biochar could be produced in 2025, with each ton capable of removing 1.26 tons of CO2. In contrast, the Puro.earth methodology allows for the production of 370,000 metric tons of biochar, with each ton removing approximately 0.88 tons of CO2. Based on estimated market prices for biochar carbon credits (per tCO2e removed), if the VM0044 project successfully issues and sells between 238,858.23 and 355,219.98 Verified Carbon Units (VCUs) in 2025, it may yield revenue between USD 42.27 million and USD 62.87 million (approximately NTD 1.2 to 1.8 billion). Under the Puro.earth methodology, approximately 328,768.02 CO2 Removal Certificates (CORCs) could be generated, with a potential income of USD 58.19 million (around NTD 1.7 billion). This implies that the carbon credit derived from rice-waste biochar can provide a substantial economic output. However, these estimates exclude project costs, transaction fees, buffer reserves, and other expenses. Thus, the actual revenue will depend on project quality, exchange rates, and prevailing market conditions. Despite its carbon reduction and economic potential, biochar production involves capital investment, energy consumption, and environmental risks such as the release of heavy metals and organic pollutants. These factors are not included in the current analysis. For any future development of carbon credit projects, comprehensive cost structures, sensitivity analyses, and uncertainty assessments must be incorporated to ensure feasibility and sustainability. This study presents a preliminary estimation and methodological simulation contextualized for Taiwan's agricultural waste scenario, demonstrating that biochar holds considerable potential for carbon sequestration and market-based applications. Nevertheless, further local empirical validation is necessary to confirm its practical effectiveness.