The traded water footprint of global energy from 2010 to 2018.

The energy-water nexus describes the requirement of water-for-energy and energy-for-water. The consumption of water in the production and generation of energy resources is also deemed virtual water. Pairing the virtual water estimates for energy with international trade data creates a virtual water trade network, facilitating analysis of global water resources management. In this database, we identify the virtual water footprints for the trade of eleven different energy commodities including fossil fuels, biomass, and electricity. Additionally, we provide the necessary scripts for downloading and pairing trade data with the virtual water footprints to create a virtual water trade network. The resulting database contains country-to-country virtual water trade from 2010-2018, broken down by commodity. The purpose of this data descriptor is to provide detailed methods and validation of the dataset beyond the complementary research publication. The resulting database provides opportunities to understand global energy-related water demands and advance future global water resources research.

A framework for estimating the United States depression burden attributable to indoor fine particulate matter exposure.

Recently published exploratory studies based on exposure to outdoor fine particulates, defined as particles with a nominal mean diameter less than or equal to 2.5 µm (PM2.5) indicate that the pollutant may play a role in mental health conditions, such as major depressive disorder. This paper details a model that can estimate the United States (US) major depressive disorder burden attributable to indoor PM2.5 exposure, locally modifiable through input parameter calibrations. By utilizing concentration values in an exposure-response function, along with relative risk values derived from epidemiological studies, the model estimated the prevalence of expected cases of major depressive disorder in multiple scenarios. Model results show that exposure to indoor PM2.5 might contribute to 476,000 cases of major depressive disorder in the US (95% confidence interval 11,000-1,100,000), approximately 2.7% of the total number of cases reported annually. Increasing heating, ventilation, and air conditioning (HVAC) filter efficiency in a residential dwelling results in minor reductions in depressive disorders in rural or urban locations in the US. Nevertheless, a minimum efficiency reporting value (MERV) 13 filter does have a benefit/cost ratio at or near one when smoking occurs indoors; during wildfires; or in locations with elevated outdoor PM2.5 concentrations. The approach undertaken herein could provide a transparent strategy for investment into the built environment to improve the mental health of the occupants.

Water and Carbon Footprints of Electricity Are Sensitive to Geographical Attribution Methods.

Environmental footprinting methods provide a means to relate the environmental externalities of electricity production to electricity consumers. Although several methods have been developed to connect the environmental footprint of electricity generation to end users, estimates produced by these methods are inherently uncertain due to the impossibility of actually tracing electricity from the point of generation to utilization. Previous studies rarely quantify this uncertainty, even though it may fundamentally alter their findings and recommendations. Here, we evaluate the sensitivity of water and carbon footprints estimates among seven commonly used methods to attribute electricity production to end users. We assess how sensitive water and carbon electricity footprint estimates are to attribution methods, how these estimates change over time, and the main factors contributing to the variability between methods. We evaluate and make available the water and carbon footprints of electricity consumption for every city across the contiguous United States for all assessed methods. We find significant but spatially heterogeneous variability in water and carbon footprint estimates across attribution methods. No method consistently overestimated or underestimated water and carbon footprints for every city. The variation between attribution methods suggests that future studies need to consider how the method selected to attribute environmental impacts through the electrical grid may affect their findings.

Unlocking the Impacts of COVID-19 Lockdowns: Changes in Thermal Electricity Generation Water Footprint and Virtual Water Trade in Europe.

Drastic changes in electricity demand have been observed since March 2020 in Europe, after several countries implemented lockdown-like measures to contain the spread of COVID-19. We investigate the sensitivity of the electricity-water nexus in the European electric grid to large-scale behavior changes during the COVID-19 pandemic lockdown-like measures. We quantify changes in the blue virtual water trade between five European countries heavily affected by COVID-19 during the same period. As a result, the consumptive water footprint of thermal power plant operations in Europe decreased by 1.77 × 106 m3/day during the COVID-19 lockdowns, compared to the average of the past four years. Reduced electricity demand accounts for 16% (0.29 × 106 m3/day) of the decrease, while the remainder is attributable to changes in the electricity generation mix toward less water-intensive technologies before 2020 and during lockdowns. Virtual water transfers associated with electricity were also affected: Italy, a hotspot of COVID-19, reduced its water footprint by 8.4% and its virtual water imports by 70,700 m3/day. Germany and France slightly reduced their domestic water footprint of electricity but increased their virtual water imports. These findings improve our understanding of the impacts of large-scale behavior and technological changes to the European electricity-water nexus.

Quantifying Energy and Water Savings in the U.S. Residential Sector.

Stress on water and energy utilities, including natural resource depletion, infrastructure deterioration, and growing populations, threatens the ability to provide reliable and sustainable service. This study presents a demand-side management decision-making tool to evaluate energy and water efficiency opportunities at the residential level, including both direct and indirect consumption. The energy-water nexus accounts for indirect resource consumption, including water-for-energy and energy-for-water. We examine the relationship between water and energy in common household appliances and fixtures, comparing baseline appliances to ENERGY STAR or WaterSense appliances, using a cost abatement analysis for the average U.S. household, yielding a potential annual per household savings of 7600 kWh and 39 600 gallons, with most upgrades having negative abatement cost. We refine the national average cost abatement curves to understand regional relationships, specifically for the urban environments of Los Angeles, Chicago, and New York. Cost abatement curves display per unit cost savings related to overall direct and indirect energy and water efficiency, allowing utilities, policy makers, and homeowners to consider the relationship between energy and water when making decisions. Our research fills an important gap of the energy-water nexus in a residential unit and provides a decision making tool for policy initiatives.