Energy–Water Nexus Analysis of Enhanced Water Supply Scenarios: A Regional Comparison of Tampa Bay, Florida, and San Diego, California

Abstract

Increased water demand and scarce freshwater resources have forced communities to seek nontraditional water sources. These challenges are exacerbated in coastal communities, where population growth rates and densities in the United States are the highest. To understand the current management dilemma between constrained surface and groundwater sources and potential new water sources, Tampa Bay, Florida (TB), and San Diego, California (SD), were studied through 2030 accounting for changes in population, water demand, and electricity grid mix. These locations were chosen on the basis of their similar populations, land areas, economies, and water consumption characters as well as their coastal locations and rising contradictions between water demand and supply. Three scenarios were evaluated for each study area: (1) maximization of traditional supplies; (2) maximization of seawater desalination; and (3) maximization of nonpotable water reclamation. Three types of impacts were assessed: embodied energy, greenhouse gas (GHG) emission, and energy cost. SD was found to have higher embodied energy and energy cost but lower GHG emission than TB in most of its water infrastructure systems because of the differences between the electricity grid mixes and water resources of the two regions. Maximizing water reclamation was found to be better than increasing either traditional supplies or seawater desalination in both regions in terms of the three impact categories. The results further imply the importance of assessing the energy-water nexus when pursuing demand-side control targets or goals as well to ensure that the potentially most economical options are considered.

Water-energy nexus for urban water systems: A comparative review on energy intensity and environmental impacts in relation to global water risks

“…A1). One thing to note is that San Diego was constantly removed from the relationship analysis as its water supply depends substantially on non-reliable imported water sources [19]. Detailed framework of the analysis is illustrated in Fig.…”

“…A study of energy use by urban water systems in major Australian cities reported that electricity consumption could increase remarkably if alternative water sources such as desalination and wastewater recycling were implemented [18]. In an energy-water nexus analysis of water supply scenarios in coastal communities (Tampa Bay and San Diego) in the USA, maximizing water reclamation was found to be a better solution compared to desalination from embodied energy, greenhouse gas (GHG) emissions and energy cost perspectives [19]. However, a study of the energy requirements needed to deliver reclaimed water up-gradient of six watersheds indicated that the water needed for the energy exceeded the amount of water that would be pumped to the various delivery locations [20].…”

Evaluating the electricity intensity of evolving water supply mixes: the case of California’s water network

“…It shows the potential range of EIs for a particular water source, depending on sitespecific conditions, and illustrates that alternatives to conventional supplies tend to have higher EIs. Studies of electricity use by water systems have been previously conducted, including some that evaluated the effects of water scarcity and diversification on energy consumption in selected cities [5][6][7][8][9]. Though energy use generally increased with scarcity, results were mixed and depended on the locations and alternatives evalu-ated.…”

Water and Energy Nexus in China: Current Situation and Future Perspective in Energy Industry, Water Industry and Agriculture

“…It will be important for China to seek the sewage treatment technologies with high efficiency and low energy consumption. Mo et al [18] reported that maximizing water reclamation was found to be better than increasing either traditional supplies or seawater desalination in both Tampa Bay and San Diego.…”