Evaluation of power generation operations in response to changes in surface water reservoir storage

We used a customized, river basin-based model of surface water rights to evaluate the response of power plants to drought via simulated changes in reservoir storage. Our methodology models surface water rights in 11 river basins in Texas using five cases: (1) storage decrease of existing capacity of 10%, (2) storage decrease of 50%, (3) complete elimination of storage, (4) storage increase of 10% (all at existing locations), and (5) construction of new reservoirs (at new locations) with a total increase in baseline reservoir capacity for power plant cooling of 9%. Using the Brazos River basin as a sample, we evaluated power generation operations in terms of reliability, resiliency, and vulnerability. As simulated water storage decreases, reliability generally decreases and resiliency and vulnerability remain relatively constant. All three metrics remain relatively constant with increasing reservoir storage, with the exception of one power plant. As reservoir storage changes at power plants, other water users in the basin are also affected. In general, decreasing water storage is beneficial to other water users in the basin, and increasing storage is detrimental for many other users. Our analysis reveals basin-wide and individual power plant-level impacts of changing reservoir storage, demonstrating a methodology for evaluation of the sustainability and feasibility of constructing new reservoir storage as a water and energy management approach.Mechanical Engineerin

Integrating Green Infrastructure Into Stormwater Policy: Reliability, Watershed Management, and Environmental Psychology as Holistic Tools for Success

As cities continue to expand, the issues of flood control and urban water quality have become major modern sustainability challenges. Green infrastructure—the use of nature-based solutions to target, treat, and store stormwater at its source—has emerged as a possible solution. While green infrastructure does offer multiple benefits for urban users, its performance is also highly variable. This Article addresses a key gap in existing literature by explicitly addressing how uncertainty in environmental and anthropogenic factors affects green infrastructure performance and integration within the Clean Water Act’s municipal separate storm sewer (MS4) regulatory program

Modeling and prediction of watershed-scale dynamics of consumptive water reuse for power plant cooling

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A Review of Energy-for-water Data in Energy-water Nexus Publications

Published literature on the energy-water nexus continues to increase, yet much of the supporting data, particularly regarding energy-for-water, remains obscure or inaccessible. We perform a systematic review of literature that describes the primary energy and electricity demands for drinking water and wastewater systems in urban environments. This review provides an analysis of the underlying data and other properties of over 170 published studies by systematically creating metadata on each study. Over 45% of the evaluated studies utilized primary data sources (data collected directly from utilities), potentially enabling large-scale data sharing and a more comprehensive understanding of global water-related energy demand. The most prevalent geographic scale of the existing literature was at the individual city scale (39%), limiting comparisons between utilities. Additionally, energy-for-water studies span 34 different countries with 11 countries having at least 4 published studies. The analyzed literature often considered greenhouse gas emissions of energy demand as an important input for life cycle analysis, highlighting the broader impact of the energy-water nexus. As a result of the review, we identify several common practices for filling data gaps, discover that research and data are primarily concentrated in three countries (Australia, China, and the United States), and offer suggestions for the future of the energy-water nexus, specifically regarding energy-for-water

Implementation of Brackish Groundwater Desalination Using Wind-Generated Electricity: A Case Study of the Energy-Water Nexus in Texas

Growing populations and periodic drought conditions have exacerbated water stress in many areas worldwide. In response, some municipalities have considered desalination of saline water as a freshwater supply. Unfortunately, desalination requires a sizeable energy investment. However, renewable energy technologies can be paired with desalination to mitigate concern over the environmental impacts of increased energy use. At the same time, desalination can be operated in an intermittent way to match the variable availability of renewable resources. Integrating wind power and brackish groundwater desalination generates a high-value product (drinking water) from low-value resources (saline water and wind power without storage). This paper presents a geographically-resolved performance and economic method that estimates the energy requirements and profitability of an integrated wind-powered reverse osmosis facility treating brackish groundwater. It is based on a model that incorporates prevailing natural and market conditions such as average wind speeds, total dissolved solids content, brackish well depth, desalination treatment capacity, capital and operation costs of wind and desalination facilities, brine disposal costs, and electricity and water prices into its calculation. The model is illustrated using conditions in Texas (where there are counties with significant co-location of wind and brackish water resources). Results from this case study indicate that integrating wind turbines and brackish water reverse osmosis (BWRO) systems is economically favorable in a few municipal locations in West TexasMechanical Engineerin

Where does solar-aided seawater desalination make sense? A method for identifying sustainable sites

AbstractGlobal water planners are increasingly considering seawater desalination as an alternative to traditional freshwater supplies. Since desalination is both expensive and energy intensive, taking advantage of favorable natural and societal conditions while siting desalination facilities can provide significant financial and environmental returns. Currently, policy makers do not use a location-specific integrated analytical framework to determine where natural and societal conditions are conducive to desalination. This analysis seeks to fill that gap by demonstrating a multi-criteria, geographically-resolved methodology for identifying suitable regions for desalination infrastructure where 1) available renewable resources can offset part of the fossil energy load; 2) feedwater characteristics reduce the total energy needed for desalination; and 3) human populations have capacity and willingness to pay for desalinated water. This work demonstrates the method with a quantitative global analysis that identifies favorable sites for solar-aided seawater reverse osmosis desalination (SWRO) based on specific target criteria. Location-based data about natural conditions (solar insolation, ocean salinity, and ocean temperature) are integrated and mapped with social indicators (water stress, prevailing water prices, and population) to identify regions where solar-aided SWRO has the highest potential. This work concludes that water-stressed tropical and subtropical cities show the highest potential for economically sustainable solar-aided SWRO

Incorporating thermoelectric power plant water use into multi-objective optimal power flow

Traditionally, power systems have been operated to minimize cost while maintaining reliability. However, extreme weather and demand events can affect traditional thermoelectric power generation operations due to their reliance on water for cooling. This paper contributes a novel multi-objective formulation of the optimal power flow (OPF) problem where cost, water withdrawal, and water consumption are minimized. Through this formulation, we assign optimization weights to water withdrawn and consumed, which can be directly incorporated into existing OPF formulations. We apply this formulation with a global mapping sensitivity analysis to a realistic case study to first demonstrate its general effectiveness under extreme climatic, hydrologic, and operational scenarios. Then, we apply a global ranking sensitivity analysis to determine the most influential generators for system performance. Through this operational scenario analysis framework, analysts can gain insights into potential system-level and component-level vulnerabilities within power systems. Such insights can be useful for informing both short-term operations as well as long-term power system planning.</p

Clean energy and water : assessment of Mexico for improved water services with renewable energy

Distributed rainwater collection and solar hot water heating are effective technologies, directly offsetting use of fossil fuel-generated electricity. Thus the 3 million people who are not connected to an electricity grid could be viewed as an opportunity to improve water services through renewable energy technologies. Additionally, policy levers such as mandates and right-pricing of water and energy can help encourage sustainable operation of established water and energy systems. The objective of this report is to assess the potential of, and barriers to, the use of decentralized renewable energy technologies for water services in Mexico with consideration for impacts from climatic stress

Energy recovery from wastewater treatment plants in the United States: A case study of the energy-water nexus

Ashlynn Stillwell is with UT Austin, David Hoppock is with Duke University, and Michael Webber is with UT Austin.This manuscript uses data from the U.S. Environmental Protection Agency to analyze the potential for energy recovery from wastewater treatment plants via anaerobic digestion with biogas utilization and biosolids incineration with electricity generation. These energy recovery strategies could help offset the electricity consumption of the wastewater sector and represent possible areas for sustainable energy policy implementation. We estimate that anaerobic digestion could save 628 to 4,940 million kWh annually in the United States. In Texas, anaerobic digestion could save 40.2 to 460 million kWh annually and biosolids incineration could save 51.9 to 1,030 million kWh annually.Mechanical Engineerin