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.

Spatially and Temporally Resolved Analysis of Environmental Trade-Offs in Electricity Generation.

The US power sector is a leading contributor of emissions that affect air quality and climate. It also requires a lot of water for cooling thermoelectric power plants. Although these impacts affect ecosystems and human health unevenly in space and time, there has been very little quantification of these environmental trade-offs on decision-relevant scales. This work quantifies hourly water consumption, emissions (i.e., carbon dioxide, nitrogen oxides, and sulfur oxides), and marginal heat rates for 252 electricity generating units (EGUs) in the Electric Reliability Council of Texas (ERCOT) region in 2011 using a unit commitment and dispatch model (UC&D). Annual, seasonal, and daily variations, as well as spatial variability are assessed. When normalized over the grid, hourly average emissions and water consumption intensities (i.e., output per MWh) are found to be highest when electricity demand is the lowest, as baseload EGUs tend to be the most water and emissions intensive. Results suggest that a large fraction of emissions and water consumption are caused by a small number of power plants, mainly baseload coal-fired generators. Replacing 8-10 existing power plants with modern natural gas combined cycle units would result in reductions of 19-29%, 51-55%, 60-62%, and 13-27% in CO2 emissions, NOx emissions, SOx emissions, and water consumption, respectively, across the ERCOT region for two different conversion scenarios.

Removal of Less Commonly Addressed Metals via Passive Cotreatment.

The viability of removing less commonly addressed metals (e.g., Cd, Cu, Ni, and Pb) in a passive cotreatment concept was tested using a microcosm-scale, three-stage batch reactor system in which acid mine drainage from an abandoned adit on Cerro Rico de Potosí and raw municipal wastewater from Potosí, Bolivia, were introduced at a 5:1 ratio. The acid mine drainage had pH 3.58, acidity 1080 mg L as CaCO equivalent, and elevated concentrations of dissolved Al, Fe, Mn, Zn, Cd, Cu, Ni, and Pb, among other metals/metalloids. The municipal wastewater had pH 9.05 and alkalinity 418 mg L as CaCO equivalent, with 5.6 and 38 mg L of nitrate and phosphate, respectively. Previous analyses noted substantial pH increase, phosphate removal, denitrification, and removal of Al, Fe, Mn, and Zn. Prompted by these results, subsequent analyses were conducted for the current study, which noted that dissolved concentrations of Cd, Cu, Ni, and Pb decreased by 78.5, 18.3, 25.5, and 45.9%, respectively. Additionally, concentrations of Ce, Cr, Gd, and La decreased throughout the system. The study revealed the broader applicability of passive cotreatment of acid mine drainage and municipal wastewater, specifically for removing metals that are often difficult to address with conventional passive treatment approaches, such as Cd, Cu, Ni, and Pb. Results could be applicable for treatment alternatives in developing and developed countries where these waste streams occur in close proximity.