Abstract

Water security has become a priority for adaptive policy and measures taken in response to climate change around the world. This is an opportunity and a challenge for the Taiwan government to establish a climate-resilient water supply portfolio to ensure water security. This study incorporated the costs of water production, intermittency, and carbon dioxide emission reduction, as well as the currently available water sources and how they will be affected by climate change, and applied optimal control theory to establish a cost-effective model to plan a long-term (2031) climate-resilient water supply portfolio for Taiwan. The study then uses the Penghu area as an empirical case study for this water supply portfolio. The results showed that desalination will become the major source of water, accounting for 71.81% of the water supply by 2031. However, this high proportion of desalination water will result in a significant increase in the unit cost of water production and the carbon footprint. Therefore, water demand management is also needed, and is recommended to ensure sustainable water resources in the Penghu area.