Energy use for urban water management by utilities and households in Los Angeles

Abstract

Reducing energy consumption for urban water management may yield economic and environmental benefits. Few studies provide comprehensive assessments of energy needs for urban water sectors that include both utility operations and household use. Here, we evaluate the energy needs for urban water management in metropolitan Los Angeles (LA) County. Using planning scenarios that include both water conservation and alternative supply options, we estimate energy requirements of water imports, groundwater pumping, distribution in pipes, water and wastewater treatment, and residential water heating across more than one hundred regional water agencies covering over 9 million people. Results show that combining water conservation with alternative local supplies such as stormwater capture and water reuse (nonpotable or indirect potable) can reduce the energy consumption and intensity of water management in LA. Further advanced water treatment for direct potable reuse could increase energy needs. In aggregate, water heating represents a major source of regional energy consumption. The heating factor associated with grid-supplied electricity drives the relative contribution of energyfor-water by utilities and households. For most scenarios of grid operations, energy for household water heating significantly outweighs utility energy consumption. The study demonstrates how publicly available and detailed data for energy and water use supports sustainability planning. The method is applicable to cities everywhere.

The Energy Trade-Offs of Transitioning to a Locally Sourced Water Supply Portfolio in the City of Los Angeles

“…The electricity demand intensity of the water supply system is relatively higher for S2, S3 and S4 (between 1.5 and 2 kWh/m 3 ) as compared to S1 (between 0.5 to 1 kWh/m 3 ). The total electricity demand intensity value estimates are comparable to the range of energy intensities reported by Porse et al [17]…”

“…The energy intensity values of the various water supplies and treatment processes applied within this framework are presented in Table 1. When available, we use EI values reflecting those received by a communication with LADWP or from LADWP's UWMP [7]; otherwise we use EI values from literature [17,34,35]. To address issues related to uncertainty in EI values, we provide electricity demand estimates based on a range of EI values that reflect values in the literature.…”

FROM THE SANITARY CITY TO THE CIRCULAR CITY? Technopolitics of Wastewater Restructuring in Los Angeles, California

“…At Hyperion, utility managers and political leaders highlight vast unused capacities for wastewater recycling when outlining a future of direct potable water reuse within Los Angeles’ city limits. While retrofitting Hyperion aims at minimizing the economic risks of regional groundwater recharge, it implies high energy costs for the advanced treatment of recycled water and its redistribution against gravity (Porse et al ., 2020). More generally, the technopolitics of fixing water scarcity through wastewater recycling at the ‘end of the pipe’ defer pressing questions about the way water is consumed, managed and governed in Los Angeles.…”

Assessing the Level of Inter-Sectoral Policy Integration for Governance in the Water–Energy Nexus: A Comparative Study of Los Angeles and Beijing

“…Recognizing the potential for the water-energy sectoral misalignment that could lead to environmentally undesirable outcomes, there has been an increased awareness of the need for a greater horizontal EPI-the motivation for this analysis. Across California, and in the Los Angeles region specifically, many researchers have begun quantifying the energy, water, and environmental tradeoffs of alternative water supply strategies like recycling [38][39][40][41][42]. However, few have explicitly examined the policy factors that help to explain EPI outcomes, as we do in the following sections.…”