Synergistic effects of green building policies on urban water resource management: A case study of typical low-carbon cities in China and Bangkok, Thailand

Under the double pressure of global climate change and urbanization, green building “water-energy synergy” has become a key link for low-carbon city governance. To address the significant difference between Chinese and Thai green building policies, this study focuses on the effects of policy differences on synergies. By combining policy text analysis, panel data regression analysis, and case comparison, the study was conducted in Shenzhen, Changning District in Shanghai, and Bangkok in Thailand. The results show that China's compulsory policies (plus economic incentives) are much better than Thailand's voluntary policies to promote the utilization of reclaimed water as well as the conservation of water and energy. Between 2018 and 2023, Shenzhen recorded a markedly stronger improvement in water-energy performance than Bangkok. The reclaimed water utilization rate in Shenzhen increased from 28% to 45%, equivalent to an average annual increase of 3.4%, whereas the corresponding increase in Bangkok was from 15% to 22%, or 1.4% /year. Over the same period, water-treatment energy consumption decreased more substantially in the Chinese case than in the Bangkok case. The differences can be attributed to three aspects: institutional strength, policy coherence, and technology adaptability. This research suggests that China should strengthen collaboration between departments and regions, while Thailand should strengthen policy restraint and adapt local technology. At the same time, we should set up a Sino-Thai cross-border policy and technology sharing mechanism in order to provide a practical reference for the collaborative management of green buildings worldwide.