水資源安全已成為全球因應氣候變遷的重要調適策略，如何建立一個氣候韌性的水資源供給組合，已成為政府維護水資安全的機會與挑戰。爰此，本研究以最適控制理論（optimal control theory），考量產水成本、間歇性成本、減碳成本、氣候變遷影響下各種水資源可供給量等因素，建立一個成本有效性（cost effectiveness）理論模型，評估長期（至2031年）最適水資源供給組合。本研究再以澎湖地區為例，實證分析澎湖地區的最適水資源組合，研究顯示，海淡水將成為澎湖地區最主要的供給水源，至2031年最適占比約71.81%，從而，也提高產水成本及碳足跡。因此，建議透過需求面管理來確保水資源的永續發展。

Water Security has become a priority adaptive policy and is used to measure the response of climate change around the world. This is an opportunity and a challenge to establish a climate resilience water supply portfolio for water security by Taiwan government. This study incorporated water production cost, intermittency cost, decarbonized cost, and available water from different sources under climate change, and applied optimal control theory to establish a cost effectiveness model to plan a long-term (2031) climate resilience water supply portfolio in Taiwan. Furthermore, this research uses Penghu area as an empirical case study of water supply portfolio in 2031. The results showed that the desalination water will become the major source of water supply which accounts for 71.81% water supply share in 2031. However, high share of desalination water will result in significant increase on unit water production cost and carbon footprint. Therefore, water demand management is also needed and recommended to sustain water resources in Penghu area.