One of the pressing issues currently faced by the water industry is incorporating sustainability considerations into design practice and reducing the carbon emissions of energy-intensive processes. Water treatment, an indispensable step for safeguarding public health, is an energy-intensive process. The purpose of this study was to analyze the energy consumption of an existing drinking water treatment plant (DWTP), then conduct a modeling study for using photovoltaics (PVs) to offset that energy consumption, and thus reduce emissions. The selected plant, located in southwestern United States, treats 0.425 m 3 of groundwater per second by utilizing the processes of coagulation, filtration, and disinfection. Based on the energy consumption individually determined for each unit process (validated using the DWTP's data), the DWTP was sized for PVs (as a modeling study). The results showed that the dependency of a DWTP on the traditional electric grid could be greatly reduced by the use of PVs. The largest consumption of energy was associated with the pumping operations, corresponding to 150.6 Wh m −3 for the booster pumps to covey water to the storage tanks, while the energy intensity of the water treatment units was found to be 3.1 Wh m −3 . A PV system with a 1.5 MW capacity with battery storage (30 MWh) was found to have a positive net present value and a levelized cost of electricity of 3.1 cents kWh −1 . A net reduction in the carbon emissions was found as 950 and 570 metric tons of CO 2 -eq year −1 due to the PV-based design, with and without battery storage, respectively.Water 2020, 12, 28 2 of 21 consumption of drinking water and wastewater treatment plants (WWTPs) has been evaluated by various studies [7][8][9][10][11][12]. Ref. [8,9] determined the energy consumption and the associated carbon emissions for water reuse plants and WWTPs, respectively, whereas [11] utilized metafrontier data envelopment analysis to analyze the energy efficiency of DWTPs. Ref. [12] reported that the city of Qingdao, China, utilized about 1% of its total energy consumption for drinking water treatment, whereas utilization was 4%-5% for the distribution of the drinking water, as well as the treatment of the generated wastewater.The changing climate, coupled with the growing population, places increased demands on water treatment facilities [13]. Between the years 1950-2000, the United States' population increased from 152.3 to 272.7 million [14], but the demands on its water supply systems increased by more than three-fold during this period, as determined by the U.S. Environmental Protection Agency (USEPA) [15]. The energy consumption of DWTPs and WWTPs corresponds to about 56-75 billion kWh year −1 [16,17], and costs about $4 billion annually [6]. These facilities account for up to 35% of a municipal government's energy budget [18]. A reduction in carbon emissions and reduced energy costs may be the motivating factors for incorporating PVs into the design of existing water infrastructures [15]. Ref. [19] determined that among t...
