Value of Reservoir Storage for Resilient Power Plant Cooling and Basin-Wide Water Availability

Author(s):  
Ashlynn S. Stillwell ◽  
Michael E. Webber

Since many thermoelectric power plants use water for cooling, the power sector is vulnerable to droughts, heat waves, and other water constraints. At the same time, large water demands for power generation can strain water availability for other users in a river basin. Opportunities exist for power plants to decrease freshwater demands, increasing both drought resiliency of power plants and water availability for other users in the basin. One particular method of decreasing freshwater demands for power plants is by incorporating reservoir storage into cooling operations. Using reservoir storage allows water to be recirculated and reused for power plant cooling, thereby decreasing water withdrawal requirements. Water storage also has the added benefit of making water available during times of shortage. While storage is known to be beneficial, no tools exist to explicitly quantify the basin-wide water availability impacts and increased power generation resiliency possible via constructing water storage at thermoelectric power plants without existing reservoirs. Here we present the results of modeling efforts regarding the value (both in terms of resiliency and water availability) of reservoir storage for power plant cooling and basin-wide water availability in the Brazos and Colorado River basins, using a customized river basin based-model along with existing Texas Water Availability Models. Results vary between river basins and different water availability models, with construction of new reservoirs generally increasing basin-wide water availability in the Brazos River basin and generally decreasing basin-wide water availability in the Colorado River basin. We conclude that the value of reservoir storage for power plant resiliency and basin-wide water availability is highly site-specific.

Author(s):  
Mary E. Clayton ◽  
Ashlynn S. Stillwell ◽  
Michael E. Webber

Texas is a large state whose water resources vary from relatively abundant in the eastern half of the state to relatively scarce in the western half. In addition, Texas is one of five states nationwide that allocates surface water through a system that merges riparian rights and prior appropriation rights. In some locations and climatic conditions, water rights have been over-allocated, creating a predicament where the legal availability of water exceeds the physical availability. Complicating matters, in 2001, the Texas Legislature established an Instream Flow Program, which conducts studies to identify appropriate flow regimes to maintain an ecologically sound environment. The findings of these instream flow studies could create challenging streamflow requirements that might cause problems for water allocation planning and management. This case study analyzes the full execution of water rights in eleven of twenty-three total river basins in Texas and the corresponding relationship to water availability. Under the full execution scenario, each water rights holder diverts the full volume allocated by a water permit with zero return flow. While this full execution scenario is not necessarily practical since most water rights holders return a portion of the diverted water after use, the Texas Commission on Environmental Quality uses the full execution water availability model to evaluate new water rights applications. Using the full execution as a baseline, we created a model to estimate the potential decrease in total water diversions in Texas river basins through the implementation of three alternative cooling scenarios at thermoelectric power plants: 1) converting current open-loop cooling technologies to closed-loop cooling towers, 2) converting all current cooling technologies to hybrid wet-dry cooling, and 3) converting all current cooling technologies to dry cooling using air-cooled condensers. Total annual diversion savings for the three alternative cooling scenarios were determined and translated into human equivalence to show the significance of implementing these cooling technology changes. By implementing these alternative cooling technologies at the plants in all eleven of the river basins considered in this analysis, water diversion could be reduced by as much as 247 to 703 million m3 annually. These diversions can supply enough water for 1.3 to 3.7 million people for one year (each using 0.53 m3 per day). Improvement in volume reliability, the percentage of total demand that is actually supplied over a time period of interest, was also examined to determine the effectiveness of converting existing thermoelectric cooling technologies to alternative cooling technologies that reduce total water diversions. Our results suggest that implementation of alternative cooling technologies at Texas thermoelectric power plants do not translate into significant improvements in volume reliability but can dramatically reduce total water diversion volumes.


2021 ◽  
Vol 11 (11) ◽  
pp. 4974
Author(s):  
Tran X. Phuoc ◽  
Mehrdad Massoudi

To our knowledge, the potential use of CO2 as a heat-transmitting fluid for cooling applications in power plants has not been explored very extensively. In this paper, we conduct a theoretical analysis to explore the use of CO2 as the heat transmission fluid. We evaluate and compare the thermophysical properties of both dry air and CO2 and perform a simple analysis on a steam-condensing device where steam flows through one of the flow paths and the cooling fluid (CO2 or air) is expanded from a high-pressure container and flows through the other. Sample calculations are carried out for a saturated-vapor steam at 0.008 MPa and 41.5 °C with the mass flow rate of 0.01 kg/s. The pressure of the storage container ranges from 1 to 5 MPa, and its temperature is kept at 35 °C. The pressure of the cooling fluid (CO2 or dry air) is set at 0.1 MPa. With air as the heat-removing fluid, the steam exits the condensing device as a vapor-liquid steam of 53% to 10% vapor for the container pressure of 1 to 5 MPa. With CO2 as the heat-removing fluid, the steam exits the device still containing 44% and 7% vapor for the container pressure of 1 MPa and 2 MPa, respectively. For the container pressure of 3 MPa and higher, the steam exits the device as a single-phase saturated liquid. Thus, due to its excellent Joule–Thomson cooling effect and heat capacity, CO2 is a better fluid for power plant cooling applications. The condensing surface area is also estimated, and the results show that when CO2 is used, the condensing surface is 50% to 60% less than that when dry air is used. This leads to significant reductions in the condenser size and the capital costs. A rough estimate of the amount of CO2 that can be stored and utilized is also carried out for a steam power plant which operates with steam with a temperature of 540 °C (813 K) and a pressure of 10 MPa at the turbine inlet and saturated-vapor steam at 0.008 MPa at the turbine outlet. The results indicate that if CO2 is used as a cooling fluid, CO2 emitted from a 1000 MW power plant during a period of 250 days could be stored and utilized.


2009 ◽  
Vol 10 (6) ◽  
pp. 1521-1533 ◽  
Author(s):  
Matthew B. Switanek ◽  
Peter A. Troch ◽  
Christopher L. Castro

Abstract In a water-stressed region, such as the southwestern United States, it is essential to improve current seasonal hydroclimatic predictions. Typically, seasonal hydroclimatic predictions have been conditioned by standard climate indices, for example, Niño-3 and Pacific decadal oscillation (PDO). In this work, the statistically unique relationships between sea surface temperatures (SSTs) and particular basins’ hydroclimates are explored. The regions where global SSTs are most correlated with the Little Colorado River and Gunnison River basins’ hydroclimates are located throughout the year and at varying time lags. The SSTs, from these regions of highest correlation, are subsequently used as hydroclimatic predictors for the two basins. This methodology, named basin-specific climate prediction (BSCP), is further used to perform hindcasts. The hydroclimatic hindcasts obtained using BSCP are shown to be closer to the historical record, for both basins, than using the standard climate indices as predictors.


2009 ◽  
Vol 10 (5) ◽  
pp. 1257-1270 ◽  
Author(s):  
Ruud Hurkmans ◽  
Peter A. Troch ◽  
Remko Uijlenhoet ◽  
Paul Torfs ◽  
Matej Durcik

Abstract Understanding the long-term (interannual–decadal) variability of water availability in river basins is paramount for water resources management. Here, the authors analyze time series of simulated terrestrial water storage components, observed precipitation, and discharge spanning 74 yr in the Colorado River basin and relate them to climate indices that describe variability of sea surface temperature and sea level pressure in the tropical and extratropical Pacific. El Niño–Southern Oscillation (ENSO) indices in winter [January–March (JFM)] are related to winter precipitation as well as to soil moisture and discharge in the lower Colorado River basin. The low-frequency mode of the Pacific decadal oscillation (PDO) appears to be strongly correlated with deep soil moisture. During the negative PDO phase, saturated storage anomalies tend to be negative and the “amplitudes” (mean absolute anomalies) of shallow soil moisture, snow, and discharge are slightly lower compared to periods of positive PDO phases. Predicting interannual variability, therefore, strongly depends on the capability of predicting PDO regime shifts. If indeed a shift to a cool PDO phase occurred in the mid-1990s, as data suggest, the current dry conditions in the Colorado River basin may persist.


Hydrology ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 58
Author(s):  
Sergio A. Rentería-Guevara ◽  
Jesús G. Rangel-Peraza ◽  
Abraham E. Rodríguez-Mata ◽  
Leonel E. Amábilis-Sosa ◽  
Antonio J. Sanhouse-García ◽  
...  

River basin delineation can be inappropriate to determine surface water availability in a country, even if it is established by its water authority. This is because the effect of agricultural and urban infrastructure in runoff direction is ignored, and the anthropogenic changes in hydrography and topography features distort the runoff. This situation is really important because water rights are granted based on volumes that are not physically accessible. The existence of this problem is demonstrated through a case of study: the Culiacan River Basin in Mexico. To overcome such a situation, this study poses criteria to revise official river basin configurations and to delineate new river basins based on digital elevation models, vector files of agricultural infrastructure, and extensive field verification. Significant differences were noticed in surface water availability calculated under distinct river basin delineations.


2020 ◽  
Author(s):  
Juan F. Salazar ◽  
Silvana Bolaños ◽  
Estiven Rodríguez ◽  
Teresita Betancur ◽  
Juan Camilo Villegas ◽  
...  

<p>Many natural and social phenomena depend on the regulation of river flow regimes. Regulation is defined here as the capacity of river basins to attenuate extreme flows, which includes the capacity to enhance low flows during dry periods of time. This capacity depends on how basins store and release water through time, which in turn depends on manifold processes that can be highly dynamic and sensitive to global change. Here we focus on the Magdalena river basin in northwestern South America, which is critical for water and energy security in Colombia, and has experienced water scarcity problems in the past, including the collapse of the national hydropower system due to El Niño 1991-1992. In this basin we study the evolution of regulation and related processes from two perspectives. First, we present a widely applicable conceptual framework that is based on the scaling theory and allows assessing the evolution of regulation in river basins, and use this framework to show how the Magdalena basin’s regulation capacity has been changing in recent decades. Second, we use data from the GRACE mission to investigate variations in water storage in the basin, and identify recent decreasing trends in both terrestrial water storage and groundwater storage. Further we show that temporal and spatial patterns of water storage depletion are likely related to the occurrence of ENSO extremes and pronounced differences between the lower and higher parts of the basin, including the presence of major wetland systems in the low lands and Andean mountains in the high lands. Our results provide insights on how to assess and monitor regulation in river basins, as well as on how this regulation relates to the dynamics of low flows and water storage, and therefore to potential water scarcity problems.</p>


1972 ◽  
Vol 94 (2) ◽  
pp. 163-168 ◽  
Author(s):  
F. K. Moore ◽  
Y. Jaluria

The natural thermal cycle of a stratified water body used for power-plant cooling will be disturbed both by heat addition and the mixing effect of withdrawal and return. A perturbation analysis for these effects is made with a model based on the assumption that a Richardson number is constant at the base of any stratified layer. On a further assumption about the profiles of wind-driven return currents, constant heat flux from that layer is inferred. This heat flux, and the diffusion coefficient at the thermocline, are the critical parameters of the simple one-dimensional line-segment model, and are chosen to give good imitation of the known natural cycle of Cayuga Lake. The model is then perturbed in terms of both heat flux and diffusion to give power-plant impact for that lake. Both transient and final cycle changes of summer and winter temperatures and stratification and overturn are calculated. It is shown that the heat and diffusion effects are comparable, and that the latter may be dominant if the discharge is diluted to meet a thermal standard. Certain implications as to strategy of water use are developed.


Author(s):  
Kwangkook Jeong

A section to delineate ‘waste heat recovery’ has been written to contribute for the ASME Power Plant Cooling Specification/Decision-making Guide to be published in 2013. This paper informs tentative contents for the section on how to beneficially apply waste heat and water recovery technology into power plants. This paper describes waste heat recovery in power plant, current/innovative technologies, specifications, case study, combined cycle, thermal benefits, effects on system efficiency, economic and exergetic benefits. It also outlines water recovery technologies, benefits in fresh water consumptions, reducing acids emission, additional cooling effects, economic analysis and critical considerations.


2013 ◽  
Author(s):  
Heather Roberts ◽  
Mitch Favrow ◽  
Jesse Coatney ◽  
David Yoe ◽  
Chenaniah Langness ◽  
...  

Thermoelectric power plants burn thousands of tons of non-renewable resources every day to heat water and create steam, which drives turbines that generate electricity. This causes a significant drain on local resources by diverting water for irrigation and residential usage into the production of energy. Moreover, the use of fossil reserves releases significant amounts of greenhouse and hazardous gases into the atmosphere. As electricity consumption continues to grow and populations rise, there is a need to find other avenues of energy production while conserving water resources. Co-combusting biomass with coal is one potential route that promotes renewable energy while reducing emissions from thermoelectric power plants. In order to move in this direction, there is a need for a low-energy and low-cost system capable of drying materials to a combustion appropriate level in order to replace a significant fraction of the fossil fuel used. Biomass drying is an ancient process often involving the preservation of foods using passive means, which is economically efficient but slow and impractical for large-scale fuel production. This effort, accomplished as an undergraduate capstone design project, instead implements an active drying system for poplar wood using theorized waste heat from the power plant and potentially solar energy. The use of small-scale prototypes demonstrate the principles of the system at a significantly reduced cost while allowing for calculation of mass and energy balances in the analysis of drying time, Coefficient of Performance, and the economics of the process. Experimental tests illustrate the need to distribute air and heat evenly amongst the biomass for consistent drying. Furthermore, the rotation of biomass is critical in order to address the footprint of the system when placing next to an existing thermoelectric power plant. The final design provides a first step towards the refinement and development of a system capable of efficiently returning an amount of biomass large enough to replace non-renewable resources. Finally, an innovative methodology applied to the dryer is discussed that could recover water evaporated from the biomass and utilize it for agricultural purposes or within the power plant thermodynamic cycle.


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