The importance of system configuration for distributed direct potable water reuse

Nature Portfolio (Springer Nature) | April 27th, 2020

Water and wastewater infrastructure worldwide faces unprecedented demand and supply conflicts that require unconventional solutions. In this study, we develop a novel mod

Water and wastewater infrastructure worldwide faces unprecedented demand and supply conflicts that require unconventional solutions. In this study, we develop a novel modelling framework to assess the environmental and economic implications of a hybrid water supply system that supplements a centralized surface water supply with distributed direct potable reuse (DPR) of municipal wastewater, as a strategy to address such challenges. The model is tested with real water and wastewater systems data from the City of Houston, Texas. Results show that supplementing the conventional centralized water supply with distributed DPR would reduce water age in the drinking-water distribution network and hence improve water quality; properly designed system configurations attain system-wide net energy savings even with the high energy consumption of existing technologies used for advanced treatment of the wastewater. A target energy efficiency for future advanced treatment technologies is identified to achieve net energy saving with all hybrid system configurations. Furthermore, distributed DPR remains financially competitive compared with other unconventional water supply solutions. The modelling framework and associated databases developed in this study serve an important research need for quantitatively characterizing distributed and hybrid water systems, laying the necessary foundation for rational design of integrated urban water systems.

The Steam Wells of California

Nature Portfolio (Springer Nature) | May 5th, 1928

The utilisation of the steam of the soffioni of Tuscany as a source of mechanical power has steadily developed since 1904 when the first pioneer experiments were

The utilisation of the steam of the soffioni of Tuscany as a source of mechanical power has steadily developed since 1904 when the first pioneer experiments were carried out at Larderello by Prince Ginori Conti. The remarkable results which have since been achieved were described in NATURE of Jan. 14 last. Similar sources of geothermal energy were first tapped in California in 1921, and since then several deep wells have been successfully sunk, some of them being superior both in pressure and steam output to any yet reported from Italy. The active region is known as ‘The Geysers,’ and lies on the western side of the St. Helena Range, one of the coast ranges of California. Along a line some twentyfive miles in length, which appears to mark a fault or shatter belt, hot springs, some of which are associated with quicksilver deposits, occur at intervals. There are no actual geysers at ‘The Geysers,’ but over an area of thirty-five acres the ground is dotted with hot springs and fumaroles and salt patches, and steam and gases are constantly seeping through the surface. A thorough investigation of the locality has been made by Dr. E. T. Allen and Dr. A. L. Day, and the results, beautifully published by the Carnegie Institution of Washington,1 add very materially to our knowledge of subterranean supplies of magmatic steam.

The Water Footprint of California’s Energy System, 1990–2012

Pacific Institute | February 1st, 2015

A new article by Julian Fulton and  Heather Cooley  evaluates the amount of water consumed in meeting California’s energy needs – also referred to as the water foot

A new article by Julian Fulton and  Heather Cooley  evaluates the amount of water consumed in meeting California’s energy needs – also referred to as the water footprint of energy. The article, published in Environmental Science and Technology, examines how the water footprint of energy changed between 1990 and 2012 – finding that the amount of water consumed substantially increased over recent decades without utilizing more of the state’s water resources, but rather by relying more heavily on water resources from outside the state. Much of that increase is attributable to the production of bioethanol, which recent energy policies have promoted to meet state greenhouse gas targets. Fulton and Cooley demonstrate that while efforts to mitigate climate change in California have been successful in reducing greenhouse gases, these policies may have shifted burdens from energy to water, rather than alleviate them. They conclude that more integrated analysis and planning of water and energy systems are needed to ensure that climate adaptation and mitigation strategies do not work at cross purposes. Abstract: California’s energy and water systems are interconnected and have evolved in recent decades in response to changing conditions and policy goals. For this analysis, we use a water footprint methodology to examine water requirements of energy products consumed in California between 1990 and 2012. We combine energy production, trade, and consumption data with estimates of the blue and green water footprints of energy products. We find that while California’s total annual energy consumption increased by just 2.6% during the analysis period, the amount of water required to produce that energy grew by 260%. Nearly all of the increase in California’s energy-related water footprint was associated with water use in locations outside of California, where energy products that the state consumes were, and continue to be, produced. We discuss these trends and the implications for California’s future energy system as it relates to climate change and expected water management challenges inside and outside the state. Our analysis shows that while California’s energy policies have supported climate mitigation efforts, they have increased vulnerability to climate impacts, especially greater hydrologic uncertainty. More integrated analysis and planning are needed to ensure that climate adaptation and mitigation strategies do not work at cross purposes.

Trade-offs across the water-energy-food nexus: A triple bottom line sustainability assessment of desalination for agriculture in the San Quintín Valley, Mexico

Environmental Science & Policy (Elsevier) | September 30th, 2020

This paper introduces a novel triple bottom line sustainability assessment to evaluate the water-energy-food nexus of desalination for agriculture. Falling technology cos

This paper introduces a novel triple bottom line sustainability assessment to evaluate the water-energy-food nexus of desalination for agriculture. Falling technology costs and rising water scarcity worldwide make desalination an increasingly attractive proposition, and agriculture is one of the main sectors grappling with its potential impacts. To explore this issue, we combine a wide range of primary and secondary environmental, economic, and social data with a triple bottom line / WEF nexus analysis, to demonstrate both the holistic sustainability impacts of desalination for agriculture, and the multi-sectoral policy environment within which desalination is adopted. We apply this approach to 54 privately-owned desalination plants that treat brackish groundwater for agricultural use in the San Quintín Valley of Baja California, Mexico. We find that subsidized energy for local agribusinesses plays an important role in making desalination economically viable in the region. This in turn fuels a large agricultural export industry that represents a significant virtual water transfer to the US market. Rapid population growth in the area driven by agricultural labor needs exacerbates the issues of social equity and sustainability that these subsidies and transfers raise. We conclude with a discussion of how to manage these identified trade-offs across the water-energy-food nexus.

Trend analysis of ground-water levels and spring discharge in the Yucca Mountain region, Nevada and California, 1960–2000

U.S. Geological Survey (USGS) | July 1st, 2002

Urban water and electricity demand data for understanding climate change impacts on the water-energy nexus

Nature Portfolio (Springer Nature) | January 23rd, 2024

Valuing energy flexibility from water systems

Nature Portfolio (Springer Nature) | September 27th, 2024

From Maven's Notebook preview: * The researchers suggest a way to measure the value of using water systems to help manage energy needs. * Water systems are generall

From Maven's Notebook preview: * The researchers suggest a way to measure the value of using water systems to help manage energy needs. * Water systems are generally very efficient at adjusting their energy use, but with current designs, they can only provide a moderate amount of power and energy under typical conditions. * Upgrading facilities to improve their energy flexibility is often a good investment and is usually cheaper than adding battery storage on-site. * Different pricing systems for energy in the U.S. and around the world have the biggest impact on whether these upgrades will be profitable. * Recognizing the value of energy flexibility is the first step to encouraging energy storage, flexible energy use, and renewable biogas generation in the water industry.

Water and Energy in California

Public Policy Institute of California (PPIC) | December 6th, 2022

Water and Energy Sector Vulnerability to Climate Warming in the Sierra Nevada: Simulating the Regulated Rivers of California’s West Slope Sierra Nevada

California Energy Commission (CEC) | August 7th, 2012

Climate warming is expected to affect the beneficial uses of water in the Sierra Nevada, impacting nearly every resident of California. This paper describes the developme

Climate warming is expected to affect the beneficial uses of water in the Sierra Nevada, impacting nearly every resident of California. This paper describes the development and results from an integrated water resource management model encompassing water operations and hydropower generation for the west slope Sierra Nevada spanning the Feather River basin in the north to the Kern River basin in the south at the weekly time step. This model application includes management of reservoirs, run-of-river hydropower plants, water supply demand locations, conveyances, and instream flow requirement. Model validation indicates that most major hydropower turbine flows were simulated well, with wetter years modeled more effectively than drier years. The results of this work indicated that hydropower generation will be reduced by approximately 8 percent with 6°C (10.8°F) warming, consistent with other studies, with a conservative parameterization of no change in precipitation. Reservoir operations adapt to capture earlier and greater runoff volumes that result from earlier and greater runoff due to climate warming. Seasonal compensation in operations is insufficient to overcome warming mediated losses.

Water and Energy Sector Vulnerability to Climate Warming in the Sierra Nevada: Water Year Classification in Non?Stationary Climates

California Energy Commission (CEC) | July 31st, 2012

This paper explores the sensitivity of water indexing methods to climate change scenarios to better understand how water management decisions and allocations will be affe

This paper explores the sensitivity of water indexing methods to climate change scenarios to better understand how water management decisions and allocations will be affected by climate change. Many water management decisions, such as environmental flow requirements and water supply allocations, are based on numerical “water year type” designations. Water year type designations vary by region and index, but most are defined by some measure of runoff in the current water year compared to average historical runoff, with numerical thresholds categorizing year types. Climate change is anticipated to alter the timing and volume of runoff, and change the relative frequency of water year types as presently defined. California’s Sacramento Valley and San Joaquin Valley Indices are used as a case study to examine climatic changes. These indices provide a framework for allocating and transferring water among users. Streamflow estimates for 1951–2099 from the climate-forced Variable Infiltration Capacity hydrologic model are used to estimate potential changes in runoff and water year type frequency, using six global circulation models for the A2 and B1 emissions scenarios. Results vary by emissions scenario and global circulation model, but indicate that critically dry water years in the Sacramento Valley and San Joaquin Valley are expected to be about 8 percent and 32 percent more likely by the latter half of the twenty-first century, respectively, if water year type definitions remain unchanged. If current water year type thresholds are maintained, more years will be classified as dry and less water will be allocated for environmental outflows, perhaps failing to provide adequate hydrologic variability to support species, habitats, and ecosystems. If thresholds are redefined to reflect the historical distribution of year types, the burden of climate change falls to consumptive users and water exporters. This case study illustrates how water policy and allocation frameworks were designed assuming climatic stationarity, and that adapting water policy (or maintaining the status quo) affects which users bear the burden of climate change.