Ensuring Reliability in Coupled Water and Electricity Infrastructure Systems Under Increasing Temperatures

With increasing heat and growing populations, desert cities are of interest for researchers who want to understand how water and electricity provision might be constrained with climate change and affect basic services. Past... [ view full abstract ]

With increasing heat and growing populations, desert cities are of interest for researchers who want to understand how water and electricity provision might be constrained with climate change and affect basic services. Past research has identified that there is a water-energy nexus at the macro level, highlighting that a city’s electricity consumption is associated with water provision and water consumption is associated with electricity provision. For example, in the US it has been found that roughly 4% of electricity generation is used in the treatment and conveyance of water, and 39% of water withdrawals are used for thermoelectric power generation. This interconnectedness implies that as extreme climate events become more frequent, any increased vulnerability in the water system may propagate to the electricity system, and vice versa. To help water and electricity utilities proactively manage their systems in the face of climate change, we used reliability engineering methodology to develop stochastic models of failure in the coupled systems under the threat of increasing temperatures. We identified which components of the respective systems are sensitive to heat, and the mechanisms that may lead to large-scale failure. From failures in physical components (such as pumps, pipes, and transmission lines) to failures in quality (such as water quality due to changes in biological and chemical process, or electricity load balancing), the chance of failure propagating to large cross-scale outages was assessed. Water and electricity utilities in Phoenix, Arizona are used as case studies, because Phoenix is a city that is projected to experience significant increases in temperatures. The types of water infrastructure considered are bulk water extraction and transmission, water treatment, water distribution, and wastewater conveyance. The types of electricity infrastructure considered are generation plants and transmission lines. Ultimately there are three main interdependencies identified between the water and electricity system that could increase in vulnerability with increasing temperatures. Namely water interruptions from blackouts or brownouts, decreased electricity generation capacity with a water interruption, and water pipe breaks causing electricity substation flooding. We find that though increasing temperatures has the potential to decrease the reliability of the coupled water and electricity systems in Arizona, proactive governance and strategic improvements to maintenance practices can mitigate the risk.