Abstract

The transition toward renewable energy has accelerated the development of self-sufficient off-grid communities. However, the intermittent nature of renewable generation necessitates large battery energy storage systems, significantly increasing infrastructure costs. Although water infrastructure represents one of the largest energy consuming sectors within such communities, its inherent operational flexibility remains largely underutilized in existing planning approaches. This paper proposes WATTER-NEX, a unified water-energy nexus co-optimization framework that simultaneously sizes and schedules photovoltaics, battery storage systems, an artificial lake, a potable water treatment plant, a potable water storage tank, and a wastewater treatment plant to achieve complete water and energy self-sufficiency. By explicitly modeling rainfall harvesting, wastewater recovery, PV soiling, and optimized PV cleaning within a single optimization framework, the proposed approach exploits waterside flexibility to complement battery energy storage and reduce overall infrastructure costs. The framework is evaluated using a representative off-grid residential community compared against a conventional rule-based benchmark under identical resource and demand conditions. Results demonstrate that WATTER-NEX reduces the total lifetime investment cost by 9.1% while decreasing the required battery storage capacity by 50% without compromising water or energy autonomy. Additional sensitivity analyses considering variations in photovoltaic generation, rainfall availability, and residential water demand demonstrate that the proposed framework maintains robust performance across a range of operating conditions. These findings highlight the potential of integrated water-energy co-optimization as a practical planning strategy for future self-sufficient renewable powered communities.

Index Terms

Water-Energy nexus; Cooptimization; Renewable microgrids; Self sufficient communities; Sustainable infrastructure.

Cite this paper:

Ann Mary Toms, Jesus Silva-Rodriguez, and Xingpeng Li, “WATTER-NEX: An Integrated Water-Energy Nexus Framework for Co-optimized Community Scale Renewable Microgrids and Water Infrastructure”, arXiv, Jul. 2026.