GTCC電廠綠色氨基電力供應鏈的技術經濟評估

Abstract

全球氣候變遷與綠電分布不均，需要系統性的整合轉型策略。本研究建立完整的「電轉氨轉電（P2A2P）」零碳供應鏈模型，利用綠氨作為儲存氫氣的載體，將國外豐富的再生能源直接運送至缺乏能源的台灣，支持 2050 年淨零碳排目標。出口國製氫分析顯示高溫固態氧化物電解槽（SOEC）的長期成本將顯著下降。雖然 SOEC 在 2020 年成本超過 2,200 $/kW，但預計自動化量產將在 2040 年降至 600 $/kW，2050 年降至 500 $/kW，證實本研究採用 1250 $/kW 作為計算基準的合理性。此外，製程整合了空氣分離裝置（ASU）提供氮氣。優化結果顯示，將合成氨反應的大量廢熱回收用於預熱電解槽蒸汽，並平衡 SOEC 熱需求，能省下大量電力，成功將整個供應鏈的總回程效率（RTE）提高到 33.13%。海運物流評估顯示，氨氣在 -34°C 即可液化運送，技術與成本顯著優於需要 -253°C 的液態氫。靈敏度分析指出船速與成本呈「U型」關係：低於 5 節會浪費時間並增加蒸發損失，高於 20 節則因水阻力導致燃料消耗飆升。模型精準算出 15 節（knots） 是台灣進口總成本最低的黃金船速。GTCC 發電模擬利用 Aspen Plus 進行，當氨燃氣渦輪複合循環電廠在 30 bar 高壓與 1750°C 高溫下運作時，發電端可達到 60.54% 的高效率，並穩定輸出 715 MW 電力。針對氨氣燃燒時氮氧化物（NOx）污染飆升至天然氣 100 倍的缺陷，本研究整合煙氣再循環（FGR）與 30 級觸媒脫硝（SCR）系統，成功將終端排煙 NOx 濃度壓低至 9 ppm，符合嚴格環保法規。 整體經濟評估全面攤提了建造與營運成本，在出口國綠電價格為 30 $/MWh 的基準下，輸配至台灣的終端度電成本收斂在 223 $/MWh。此成本架構面對國際碳稅風險時展現出極佳的經濟韌性。本研究透過量化模擬結果證明綠氨進口策略的可行性，為台灣未來 2050 年規劃綠能採購與電網動態平衡時，提供了一套具備實務價值的評估架構與定量分析視角。

Global climate change and the uneven distribution of green electricity require integrated, system-level energy transition strategies. This study develops a complete Power-to-Ammonia-to-Power (P2A2P) zero-carbon energy supply chain model using green ammonia as a hydrogen storage medium to transport abundant renewable energy from international exporters directly to energy-scarce Taiwan, supporting the 2050 net-zero emissions target. Exporter hydrogen production analysis reveals significant long-term cost reductions for high-temperature Solid Oxide Electrolyzer Cells (SOEC). While SOEC capital costs exceeded 2,200 $/kW in 2020, automated mass production is projected to drive costs down to 600 $/kW by 2040 and 500 $/kW by 2050. This decline validates using 750 $/kW as a reasonable calculation basis in this study. Furthermore, an Air Separation Unit (ASU) is integrated to supply the required nitrogen. Process optimization shows that recycling ammonia synthesis waste heat to preheat electrolyzer steam, while balancing SOEC thermal demands, saves substantial electricity and raises the total supply chain Round-Trip Efficiency (RTE) to 33.13%. Maritime transport evaluations show that liquefying ammonia at -34°C offers major advantages over liquid hydrogen at -253°C. Sensitivity analysis identifies a "U-shaped" relationship between shipping speed and delivered costs: sailing below 5 knots incurs heavy time and boil-off penalties, while exceeding 20 knots spikes fuel consumption due to water resistance. The model identifies 15 knots as the optimal shipping speed that minimizes total import costs for Taiwan. GTCC power generation simulations using Aspen Plus show that an ammonia gas turbine combined cycle plant operating at 30 bar and 1750°C achieves a power generation efficiency of 60.54% and a stable output of 715 MW at the destination. To mitigate nitrogen oxide (NOx) emissions—which can spike to 100 times that of methane—the integration of Flue Gas Recirculation (FGR) and a 30-block Selective Catalytic Reduction (SCR) system successfully curtails exhaust NOx down to 9 ppm, meeting strict environmental standards. Overall economic evaluation factoring in all construction and operating costs shows that under a baseline export green electricity price of 30 $/MWh, the final delivered cost of electricity generated in Taiwan converges at 223 $/MWh. This framework demonstrates strong financial resilience against potential international carbon taxes. These quantitative model outcomes prove the viability of the green ammonia import strategy, serving as a practical evaluation framework and a quantitative analysis perspective for Taiwan’s future 2050 green procurement and grid stability.