Kriti Acharya

Hybrid water supply systems (WSSs) integrating centralized and decentralized water systems have gained increasing interest in recent years to enhance water service sustainability and system resilience. An example of implementing hybrid WSSs is water microgrids, inspired by energy microgrids. Water microgrids can be depicted as a network (grid) of localized networks (sub-grids) comprising local water sources and their storage and distribution systems that operate in conjunction with a central WSS. They can operate in both ‘grid-connected or ‘islanded’ mode and support interaction and demand trade-offs with centralized WSSs at varying degrees of decentralization, providing flexibility and increased control over water resources. However, the concept of water microgrids is still in its infancy, and their application is limited due to a lack of design guidance and frameworks. This paper provides a comprehensive review of water microgrids, discussing the concept, design, benefits, and potential challenges by drawing insights from energy microgrids, and also discusses the standpoint in comparison with centralized, decentralized, and hybrid WSSs. It also explores integration of decentralized and hybrid infrastructure within existing WSSs, highlighting the balance between localized optimization and systemwide sustainability. The findings aim to broaden understanding of water microgrids, assessing their applicability and operational strategies in urban settings.

Traditional centralized water systems are facing sustainability challenges due to climate and socioeconomic changes, extreme weather events, and aging infrastructure and their uncertainties. The energy sector has addressed similar challenges using the microgrid approach, which involves decentralized energy sources and their supply, improving system resilience and sustainable energy supply. This study investigated the resilience effects of water microgrids, which feature operational interactions between centralized and local systems for sustainable water supply. A lab-scale water distribution model was tested to demonstrate centralized, decentralized, and microgrid water systems under the disruption scenarios of pump shutdown, pump rate manipulation, and pipe leaks/bursts. The water microgrids integrate centralized and local systems’ operations, while the decentralized system operates independently. Then, functionality-based resilience and its attributes were evaluated for each disruption scenario. The results reveal that, overall, the microgrid configuration, with increased water supply redundancy and flexible operational adjustment based on system conditions, showed higher resilience, robustness, and recovery rate and a lower loss rate across disruption scenarios. The resilience effect of water microgrids was more evident with longer and more severe disruptions. Considering global challenges in water security under climate and socioeconomic changes, the findings suggest insights into a hybrid water system as a strategy to enhance resilience and water use efficiency and provide adaptive operations for sustainable water supply.