skip to main content


Title: 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 energy-for-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.

 
more » « less
Award ID(s):
1845931
NSF-PAR ID:
10303278
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
Environmental Research Communications
Volume:
2
Issue:
1
ISSN:
2515-7620
Page Range / eLocation ID:
Article No. 015003
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    Climate change, drought, and chronic overdraft represent growing threats to the sustainability of water supplies in dry environments. The Monterey/Salinas region in California exemplifies a new era of integrated or “one water” management that is using all of the water it can get to achieve more sustainable supplies to benefit cities, agriculture, and the environment. This program is the first of its kind to reuse a variety of waters including wastewater, stormwater, food industry processing water, and agricultural drainage water. This study investigates the partnerships, projects, and innovations that shape Monterey’s integrated water network in order to better understand the challenges and opportunities facing California communities as they seek to sustainably manage peri-urban water supplies. Water reuse in the Monterey region produces substantial economic and environmental benefits, from tourism and irrigation of high-value crops to protection of groundwater and increases in environmental flows and water quality. Water resource managers in other communities can learn from Monterey’s success leveraging local needs and regional partnerships to develop effective integrated water solutions. However, key challenges remain in resolving mismatched timing between water availability and demand, funding alternative water supplies, and planning effectively under uncertainty. Opportunities exist to increase Monterey’s recycled water supply by up to 50%, but this requires investment in seasonal storage and depends on whether desalination or additional recycling forms the next chapter in the region’s water supply story. Regulatory guidance is needed on seasonal subsurface storage of tertiary-treated recycled water as distinct from potable recharge. By increasing the supply of recycled water to Monterey’s indirect potable use system, the region’s potential need for seawater desalination may be delayed as much as 30 years, resulting in cost and energy savings, and giving the opportunity to resolve present planning concerns. 
    more » « less
  2. Abstract

    Urban communities around the world are grappling with the challenges associated with population increases, drought, and projected water shortages. With a substantial global shortfall between water supply and demand expected by 2030, water planning strategies must adapt to a new reality characterized by higher temperatures and less precipitation, requiring new ways of thinking about water management, use, and governance. Commonplace strategies such as water conservation and nonpotable water reuse might not be sufficient to adequately stretch water supplies in water‐scarce parts of the industrialized world. In the United States, planned potable water reuse (i.e., purification of domestic wastewater for reuse as drinking water) is emerging as a way forward to mitigate water shortages without significant changes to lifestyle, behavior, or infrastructure. But potable reuse is not the only solution: paradigm shifting and disruptive options that more holistically address water scarcity, such as composting toilets and market‐based approaches to water use, are also gaining traction, and they could be pursued alongside or instead of potable water reuse. However, these options would require more significant changes to lifestyles, behavior, infrastructure, and governance. While all of the options considered offer advantages, they each come with new concerns and challenges related to cost, public perception, social norms, and policy. The goal of this work is to consider a number of plausible solutions to water scarcity—partial and complete, traditional and disruptive—to stimulate forward‐looking thinking about the increasingly common global problem of water scarcity.

    This article is categorized under:

    Engineering Water > Sustainable Engineering of Water

    Engineering Water > Planning Water

     
    more » « less
  3. Abstract

    Rapidly growing cities along the Interstate‐85 corridor from Atlanta, GA, to Raleigh, NC, rely on small rivers for water supply and waste assimilation. These rivers share commonalities including water supply stress during droughts, seasonally low flows for wastewater dilution, increasing drought and precipitation extremes, downstream eutrophication issues, and high regional aquatic diversity. Further challenges include rapid growth; sprawl that exacerbates water quality and infrastructure issues; water infrastructure that spans numerous counties and municipalities; and large numbers of septic systems. Holistic multi‐jurisdiction cooperative water resource planning along with policy and infrastructure modifications is necessary to adapt to population growth and climate. We propose six actions to improve water infrastructure resilience: increase water‐use efficiency by municipal, industrial, agricultural, and thermoelectric power sectors; adopt indirect potable reuse or closed loop systems; allow for water sharing during droughts but regulate inter‐basin transfers to protect aquatic ecosystems; increase nutrient recovery and reduce discharges of carbon and nutrients in effluents; employ green infrastructure and better stormwater management to reduce nonpoint pollutant loadings and mitigate urban heat island effects; and apply the CRIDA framework to incorporate climate and hydrologic uncertainty into water planning.

     
    more » « less
  4. Abstract

    It is widely acknowledged that distributed water systems (DWSs), which integrate distributed water supply and treatment with existing centralized infrastructure, can mitigate challenges to water security from extreme events, climate change, and aged infrastructure. However, it is unclear which are beneficial DWS configurations, i.e., where and at what scale to implement distributed water supply. We develop a mesoscale representation model that approximates DWSs with reduced backbone networks to enable efficient system emulation while preserving key physical realism. Moreover, system emulation allows us to build a multiobjective optimization model for computational policy search that addresses energy utilization and economic impacts. We demonstrate our models on a hypothetical DWS with distributed direct potable reuse (DPR) based on the City of Houston's water and wastewater infrastructure. The backbone DWS with greater thanlink and node reductions achieves satisfactory approximation of global flows and water pressures, to enable configuration optimization analysis. Results from the optimization model reveal case‐specific as well as general opportunities, constraints, and their interactions for DPR allocation. Implementing DPR can be beneficial in areas with high energy intensities of water distribution, considerable local water demands, and commensurate wastewater reuse capacities. The mesoscale modeling approach and the multiobjective optimization model developed in this study can serve as practical decision‐support tools for stakeholders to search for alternative DWS options in urban settings.

     
    more » « less
  5. Abstract

    Nonresidential irrigation is a unique and important yet understudied urban water sector. Knowing how urban irrigators use water is critical for projecting future demands, planning diverse supply portfolios, and designing conservation strategies. In this study, we developed a holistic, analytical approach to advance knowledge about the temporal and spatial dimensions of nonresidential outdoor water use, also known as large landscape irrigation. Our approach employed data from two forthcoming technologies: dedicated irrigation meters and smart meters (i.e., advanced metering infrastructure). We then applied our methodology to a case study city in the San Francisco Bay Area, California, from 2013 to 2016 during a historic, high‐profile drought. Importantly, we uncovered behavioral differences between customers with potable versus recycled water connections and different subsectors of large landscape irrigation. Overall, conservation patterns mimicked those across California. Although they saved at lower rates, customers with recycled water followed similar conservation trends despite receiving no mandates. A weekly water use model revealed drivers of water demand, while spatial analyses showed hot and cold spots of conservation, with those in higher‐income areas conserving less as the drought progressed. A conditional inference tree partitioned diverse customers based on their conservation rates, identifying characteristics of customers who could provide the most savings in future droughts. As increasing water scarcity and population growth prompt water suppliers to optimize resources through supply diversification and demand‐side management, large landscape irrigation presents one avenue for achieving those goals.

     
    more » « less