Optimal design of energy and water supply systems for low-income communities involving multiple-objectives

This paper proposes the use of Combined Heat and Power systems for providing water and energy, and thermal and electric utilities, in geographically isolated communities, where the interconnection with the grid is not available. A common design practice is to implement different energy storage technologies, usually batteries, for reducing the gap between energy generation and electric consumption. However, in communities with low incomes, it is not possible to use batteries due to the high capital costs. This work presents a new approach for providing simultaneously electricity and water using the fresh water extraction and storage for reducing the gaps between generation and consumption. The proposed approach is based on a mixed integer nonlinear programming formulation, which accounts for the optimal selection of multiple combined heat and power technologies and the sizing of the water storage and pumping technologies. A multi-objective analysis is presented considering as objective functions the economic costs and environmental impact associated with the space used by the system and water consumption. A community in the mountains of Mexico is presented as case study. The results show that it is possible to provide energy and water at low costs and reducing the environmental impact, reaching a trade-off between the considered objective functions.