Browsing by Subject "Water consumption"
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Item Climate action strategies for the University of Texas at Austin(2010-05) Hernandez, Marinoelle; Eaton, David J.; Walker, Jim H.This report analyzes the current greenhouse gas emissions inventory for The University of Texas at Austin (UT-Austin), reviews the carbon reduction strategies being implemented at UT-Austin and other peer institutions, and offers recommendations for strategies that could reduce greenhouse gas emissions at UT-Austin in the future.Item Gas exchange and water use efficiency of grain sorghum(Texas Tech University, 1990-05) Peng, ShaobingGrain sorghum [Sorghum bicolor (L.) Moench] production is usually confined to environments which are considered too dry and hot for other cereals to be productive. Increasing yield and water use efficiency (WUE) of grain sorghum through identification and utilization of superior germplasm in breeding programs is a major goal in the improvement of this crop. Breeding for increased WUE has been limited by the lack of screening criteria and methods that could be used to select desirable genotypes from large populations under field conditions. This study was conducted to determine whether genotypic differences in WUE and gas exchange traits are present and to determine whether the variation in gas exchange rates and efficiencies reflected the genotypic differences in WUE and thereby, could be used as a screening criteria for identifying genotypes of grain sorghum with higher WUE. Five sorghum genotypes (TX 378, TX 430, SC 35, TX 399, and TX 2741) which are parental lines used in hybrid seed production were tested in the greenhouse and field during 1989 under well watered conditions. In the greenhouse study, individual entries were planted in plastic pots containing 10 kg of sterilized potting mix. The field experiment was conducted on an Amarillo loamy fine sand. In both studies, shoot biomass production, amount of water used, and leaf area development were monitored during die growing season. Water use efficiency was calculated as shoot biomass production per unit water use. Gas exchange measurements were made throughout the vegetative stage on uppermost fully expanded leaves and whole canopy using a portable photosynthesis system. Gas exchange efficiency was expressed as the ratio of photosynthetic rate (A) to transpiration rate (T). The sorghum genotypes exhibited significant variation for A, A/T, shoot biomass production, and WUE. TX 378, TX 430, and SC 35 had higher A, A/T, shoot biomass production, and WUE than TX 399 and TX 2741. No consistent genotypic variation was observed for T or whole plant water use rates. Single leaf measurements of gas exchange traits (A and A/T) reflected single plant and whole canopy WUE differences among the genotypes largely due to the positive correlation between A and shoot biomass production. In addition, there was a positive correlation among the genotypes between leaf area and A. The results indicate that measurements of A and leaf area may be used to select for increased WUE in grain sorghum.Item Sustainable energy systems : the environmental footprints of electricity generation systems : mechanisms for managing electricity, water resources and air quality(2012-08) Alhajeri, Nawaf Salem; Allen, David T.; McDonald-Buller, Elena; Corsi, Richard; Webster, Mort; Webber, MichaelThis thesis examines the response of air pollutant emissions, water use and carbon emissions from electric power supply systems (electrical grids) to market forces and natural and human disruptions. Specifically, the response of electrical grid operation decisions to emissions pricing and other factors, such as drought restrictions, is examined. The grid of the Electricity Reliability Council of Texas (ERCOT) is used as a source of data, and as a spatial and temporal test-bed. Price signals for NOx emissions have the potential to reduce NOx emissions from the ERCOT grid by up to 50%. In addition to lowering NOx, there are co-benefits to introducing NOx prices, including reductions in the emissions of SOx (24.9% to 70.9%), Hg (16.8% to 81.3%) and CO2 (8.7% to 21.1%). Water consumption was also decreased by 4.3% to 8.2%. The costs of redispatching electricity generation to reduce NOx emissions are, in many scenarios, comparable to conventional control costs. Higher CO2 prices produce many of the same changes in electricity generation as increases in NOx prices, but the simultaneous application of NOx and CO2 pricing produces complex effects. Under stress, such as drought induced water scarcity, dispatching decisions have the potential to increase water availability in regions in which drought is a concern. This dispatching had relatively small impacts on total water consumption summed over all regions of the ERCOT grid. However, the dispatching scenarios resulted in net increases in NOx, SOx, and CO2 emissions rates summed over all regions of the grid, particularly in regions that were absorbing the electricity generation that was exported out of the drought impacted regions. The costs of electricity dispatching, per volume of water consumption reduced in the drought impacted region, was generally greater than the cost of implementing dry cooling in the same facilities at high electricity demand levels, but comparable to dry cooling at low to moderate demand levels. Finally, while changes in total emissions can be used as a surrogate for air quality impacts, actual changes in air pollutant concentrations, such as ozone, exhibit complex spatial and temporal patterns in response to redispatching, including the creation of hot spots of elevated concentrations.