Browsing by Subject "Economic analysis"
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Item An integrated assisted history matching and embedded discrete fracture model workflow for well spacing optimization in shale gas reservoirs(2020-12) Li, Qiwei, M.S. in Engineering; Sepehrnoori, Kamy, 1951-An appropriate well spacing plan is critical for the development of shale reservoirs. The biggest challenge for well spacing optimization is interpreting the subsurface uncertainties associated with hydraulic and natural fractures. However, most studies have calibrated the uncertainties by single history matching, which does not take the non-uniqueness of history matching into account. Therefore, the objective of this study is to develop an integrated assisted history matching (AHM) and embedded discrete fracture model (EDFM) workflow for well spacing optimization by considering multiple uncertainty realizations and economic analysis. We applied this workflow for an actual shale gas reservoir without natural fractures and another shale gas reservoir with complex natural fractures. Firstly, we captured the distribution of uncertainty parameters of matrix and fractures using AHM based on the production data. Uncertain parameters of matrix include matrix permeability, matrix porosity, and three relative permeability parameters, while hydraulic fractures uncertainties consist of fracture height, half-length, width, conductivity, and water saturation. And the uncertain parameters of natural fractures are the number of natural fractures, conductivity, and length. The input cases can be prepared by combining AHM solutions with different well placement scenarios. Then we performed reservoir simulation to all cases and forecasted the gas and water production in the long-term. Gas estimated ultimate recovery (EUR) per well can be analyzed to predict the influence of well interference and the critical well spacing. Finally, we estimated the net present value (NPV) for all cases and predicted it by k-nearest neighbors (KNN) proxy model to better understand the relationship between well spacing and NPV. The optimum well spacing can be obtained from the maximum NPV. Our integrated workflow is straightforward and practical, with great accuracy, and efficiency. We can predict the optimum well spacing for most shale gas reservoirs by capturing the multiple realizations of uncertaintiesItem Analysis of a novel thermoelectric generator in the built environment(2011-08) Lozano, Adolfo; Webber, Michael E., 1971-; Schmidt, Philip S.This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source.Item Economic analysis and risk management for the South Sumatra Natural Gas Pipeline Project in Indonesia(2019-05-03) Kim, Dong Hyun (M.S. in Energy and Earth Resources); Eaton, David J.The objective of this thesis is to analyze economic and risk factors for the South Sumatra Natural Gas Pipeline Project in Indonesia. The economic analysis aims to support Korea Gas Corporation (KOGAS)’s decision regarding next steps, such as a feasibility study or front end engineering design for the project. In scenario analysis, WACC ought to be less than 9 percent and the growth rate of gas demand is larger than 3 percent to meet KOGAS’s requirements for an investment. Monte Carlo simulation showed that the project has a project NPV of 90 million USD and project IRR of 11 percent on Scenario 1 which is the least profitable scenario. It means that this project could be a viable project for KOGAS, but there is a 36 percent probability that the project IRR would be less than KOGAS’ investment threshold. A sensitivity analysis indicates that a toll fee has the greatest impact on the project IRR among six variables. This thesis establishes mitigation strategies against the South Sumatra Natural Gas Pipeline Project’s significant risks.Item Economic analysis of wind and solar energy sources of Turkey(2011-05) Erturk, Mehmet; Groat, Charles G.; Jablonowski, Christopher J.Renewable energy sources have become very popular in the last years in electricity generation thanks to the technological developments, the increase in the price of fossil fuels and the environmental concerns. These factors have also prompted Turkey to utilize her very rich renewable energy sources to meet the demand increasing around 7% annually. In this study, solar and wind energy potential of Turkey is analyzed in terms of its economics to find out whether these sources are real alternatives to fossil fuels in electricity generation. Before this analysis, wind and solar energy technologies and costs and wind and solar energy potential of Turkey are discussed. Then, models are set up for five technologies which are onshore wind, offshore wind, solar PV, solar trough and solar tower technologies models to calculate cash flows which are used to calculate payback, NPV, IRR, LCE and shut-down price to conduct economic analysis. In addition to base case scenario, uncertainty analysis is done for the most promising technologies which are onshore wind and solar tower technologies by evaluating NPV and LCE under uncertain environment. The main finding of these analyses is that only onshore wind projects are attractive in Turkey; none of other technologies is attractive. However, with a minor increase in the regulated price for solar thermal electricity, tower plant projects will also be attractive.Item Economic analysis on energy efficiency certificate trading in Texas(2021-04-02) Khomaini, Achmad Zulfikar; Zarnikau, Jay William, 1959-; Spence, David B.Energy efficiency is the key to sustainable development; thus, decoupling economic growth from unsustainable energy demand is essential. The Public Utility Commission of Texas (PUCT) has mandated several utility companies' energy efficiency annual goals. While some utilities had been able to easily meet the goals, the other utility companies had struggled to meet the objectives. It is a certificate issued by independent certifying bodies confirming market actors' energy savings claims because of energy efficiency improvement measures. The certificate trading enables utilities buying certificates to meet their energy efficiency goal. If a utility company can implement more energy efficiency programs in terms of the number of kWh/kW with a relatively lower cost beyond their goal, they can sell their energy saving excess to other utility companies that have to implement more expensive energy efficiency measures. The simulation aims to minimize the cost of meeting the goal for energy reduction through energy programs by selecting the least-cost programs. This simulation will calculate the overall cost saving. There are two types of energy efficiency goals which are based on kW and kWh. Additional constraints are also implemented such as Mandatory low-income programs (MLIP) to ensure each utility implements low-income households' measures and 30% Within Service Area (WSA) to ensure 30% of their goal is achieved by their own program. This research suggested that enabling energy efficiency certificate trading minimizes the total cost for achieving the Texas energy efficiency goal. In almost all simulated cases, all utilities financially benefit from joining the trading system because the utility companies spend less to achieve their own energy efficiency goal. In all cases, adding MLIP and WSA constraints increases the total cost to achieve the goal. Furthermore, in terms of the policy, Stakeholder analysis suggested that policymakers consider each utility's different role. Utilities that are within the Electric Reliability Council of Texas (ERCOT) electricity market will have different business structures compared to the ones who are not. Furthermore, integrating Energy efficiency certificate and Renewable Energy Credit would also be more complicated, considering, not all utilities have an obligation to achieve the Renewable Energy Credit target.Item Expanded newborn screening in Texas : a cost-effectiveness analysis using Markov modeling(2009-05) Tiwana, Simrandeep Kaur; Rascati, Karen L.Texas House Bill 790 resulted in the expansion of the newborn screening panel from 7 to 27 disorders. The long-term economic implications of this expansion have not been studied. The objective of this study was to estimate the incremental cost-effectiveness of the expanded newborn screening program compared to the previous standard screening in Texas. A Markov model (for a hypothetical cohort of Texas births in 2007) was constructed to compare life-time costs and QALYs between the expanded newborn screening and pre-expansion newborn screening. Estimates of costs, probabilities of sequelae, and utilities for disorder categories were obtained from Texas statistics, the literature, and expert opinion. A baseline discount rate of 3% was used for both costs and QALYs, with a range of 0% to 5%. Analyses were conducted from a payer's perspective, so only direct medical cost estimates were included. The life-time incremental cost-effectiveness ratio (ICER) for expanded versus pre-expansion screening was about $12,000/QALY. Probabilistic sensitivity analysis using key variables showed that results ranged from about $9,500 to $13,000 /QALY. This range is well below the commonly cited willingness to pay threshold of $50,000/QALY. Therefore, expanded newborn screening results in additional expense to the payer but also improves patient outcomes by preventing avoidable morbidity and mortality. The screened population benefits from greater QALYs as compared to the unscreened population. Overall, expanded newborn screening in Texas was estimated to be a cost-effective option as compared to unexpanded newborn screening.Item Mass transfer coefficients and effective area of packing(2015-05) Wang, Chao; Rochelle, Gary T.; Seibert, Frank; Bonnecaze, Roger; Maynard, Jennifer; Eldridge, Bruce; Corsi, RichardThe effective mass transfer area (a [subscript e]), liquid film mass transfer coefficient (k [subscript L]), and gas film mass transfer coefficient (k [subscript G]) of eleven structured packings and three random packings were measured consistently in a 0.428 m packed column. Absorption of CO₂ with 0.1 gmol/L NaOH with 3.05 m packing was used to measure a [subscript e], while air stripping of toluene from water with 1.83 m packing was used to measure k [subscript L], and absorption of SO₂ with 0.1 gmol/L NaOH with 0.51 m packing was used to measure k [subscript G]. The experiments were conducted with liquid load changing from 2.5 to 75 m³/(m²*h) and gas flow rate from 0.6 to 2.3 m/s. Packings with surface area from 125 to 500 m²/m³ and corrugation angle from 45 to 70 degree were tested to explore the effect of packing geometries on mass transfer. The effective area increases with packing surface area and liquid flow rate, and is independent of gas velocity. The packing corrugation angle has an insignificant effect on mass transfer area. The ratio of effective area to surface area decreases as surface area increases due to the limit of packing wettability. A correlation has been developed to predict the mass transfer area with an average deviation of 11%. [Mathematical equation]. The liquid film mass transfer coefficient is only a function of liquid velocity with a power of 0.74, while the gas film mass transfer coefficient is only a function of gas velocity with a power of 0.58. Both k [subscript L] and k [subscript G] increase with packing surface area, and decrease with corrugation angle. A new concept, Mixing Point Density, was introduced to account for effect of the packing geometry on k[subscript L] and k [subscript G]. Mixing Point Density represents the frequency at which liquid film is refreshed and gas is mixed. The mixing point density can be calculated by either packing characteristic length or by surface area and corrugation angle: [mathematical equation]. The dimensionless k [subscript L] and k [subscript G] models can then be developed based on the effects of liquid/gas velocity, mixing point density, packing surface area: [mathematical equation] [mathematical equation]. Mi is the dimensionless form of Mixing Point Density (M), which is M divided by a [subscript P]³. Because Mi is only a function of corrugation angle (θ), it is a convenient transformation to represent the effect of θ on mass transfer parameters. An economic analysis of the absorber was conducted for a 250 MW coal-fired power plant. The optimum operating condition is between 50 to 80 % of flooding, and the optimum design is to use packing with 200 to 250 m²/m³ surface area and high corrugation angle (60 to 70 degree). The minimum total cost ranges from $4.04 to $5.83 per tonne CO₂ removed with 8 m PZ.Item Model-based cost analysis for pressure and geochemical-based monitoring methods in CO2-EOR fields: application to field A(2016-05) Bolhassani, Behnaz; Young, Michael H.; Hovorka, Susan D.; Sun, Alexander Y.Decision making using monitoring data from CO2 geological storage (GS) projects can be multifaceted and complex because of geological, environmental, political, and economic factors. This study primarily focuses on economic and technical aspects of monitoring projects for CO2. The focus of this research is to compare the economic effectiveness of pressure-based monitoring (PBM) and geochemical-based monitoring (GBM) on CO2 leakage detection in CO2-EOR sites where risk for leakage assumed to be plugged and abandoned (P&A) wells, however methodology can be easily applied to CO2 storage in saline aquifers as well. PBM can detect leakage from pressure anomalies, while GBM method detects leakage from alteration in fluid chemistry. In this paper, analytical and semi-analytical models for PBM and GBM techniques were applied to calculate the number of monitoring wells required for monitoring anomalies, which could be due to leakage of CO2. In this study, we assumed that leakage through P&A wells represents the main risk factor. The goals of this study are to determine the cost effectiveness of PBM and GBM as a means to maximize the spatial coverage of the monitoring network in the vicinity of P&A wells. We used different analytical models for PBM and GBM, and overlaid the spatial coverage of each well onto a typical Texas Gulf Coast field site (known as Field A), thus identifying the intersection of each monitoring well and potentially leaking P&A well. Then, based on the available cost data, the costs of each PBM and GBM well were estimated and the two monitoring techniques were compared economically, assuming a pre-determined budget is available to invest on monitoring. The results showed that the spatial coverage of each PBM well was much higher than each GBM wells, and that the total capital and operational cost per PBM well was lower than each GBM well. For theoretical site used in this work, only 29 PBM wells were needed for full coverage of the field site, while 169 GBM wells were required. Therefore, we concluded that PBM technique is a more cost effective option, considering the parameters and assumption in this case study.Item A Predictive Model for Water and Polymer Flooding(1984-04) Jones, Ralph Steven Jr; Lake, Larry W.; Pope, Gary A.A "predictive evaluation model" (PEM) has been developed for feasibility analysis of water and polymer flooding. It is designed to produce a reservoir performance prediction suitable for economic analysis, with small computing time and input data requirements. The tools previously available for this purpose range from "binary" screening guides to sophisticated reservoir simulators. Binary screening guides do not consider the composite effect of reservoir parameters, and offer little information about economic feasibility. Many simplified prediction methods are available for waterflooding, and some for special cases of polymer flooding; however, the assumptions inherent in these methods limit applicability. Mathematical reservoir simulators are excellent prediction tools, but operational costs are often prohibitive when screening prospective reservoirs. The PEM was developed to fill the gap between simplified methods and reservoir simulators. The PEM uses "vertical equilibrium" methods to generate pseudorelative permeability curves, which are then used in a one-dimensional finite-difference model; this accounts for vertical heterogeneity and crossflow between communicating layers. Areal sweep correlations for pattern floods are then applied, followed by injection rate calculations. The PEM is based on the assumption of incompressible oil-water flow, but includes a correction for initial gas saturation. The resulting output consists of cumulative produced volumes and producing rates as a function of time for oil, water, and gas, as well as injection rates and volumes. The PEM considers many important flow properties which usually are accounted for only in reservoir simulators and requires a small fraction of the computing time. Polymer solution flow properties accounted for in the PEM include permeability reduction, adsorption, viscous fingering of drive water into polymer slug, and viscosity, all as functions of polymer concentration; the 11 inaccessible pore volume11 effect is also included. Predictions can also be made for tertiary polymer floods initiated after waterflooding. Injection rate calculations account for variations with time due to reservoir flow characteristics; the nonNewtonian behavior of polymer solutions is also considered. Because the PEM is designed for preliminary analysis, where extensive reservoir and fluid data may not be available, it includes routines for estimating relative permeability and capillary pressure curves. Although it is based on a stratified model, it can generate layers of different permeability given the Dykstra-Parsons permeability variation. These features reduce data requirements to a minimum when necessary, but the PEH also accepts more extensive data if it is available. Sensitivity studies were conducted to show the effects of various reservoir and fluid parameters on oil recovery and injection rates, for both water and polymer flooding. The PEM was validated by matches with a cross-sectional polymer flood simulator and other published simulation results; good agreement was observed. History matching of actual field data was successfully performed for a pilot waterflood and a field-scale polymer flood.Item A review of the methods of economic analysis of nuclear power plants(2011-05) Cavender, Brittainy Anne; Popova, Elmira; Hess, StephenNuclear power plants across the United States are reaching the end of their current operating licenses, forcing decision makers to think about the way forward. As they consider the best alternatives for dealing with aging nuclear plants, it is becoming increasingly important to have an accurate method for calculating the long-term costs of nuclear power plants. This report begins by investigating the methodologies currently used in these calculations. They focus on the uncertainty associated with deregulated electricity markets and can be broken down into two main categories: discounted cash flow and real options analysis. Next the report discusses the limitations of the current methodologies, focusing specifically on those aspects of evaluation that are currently eclipsed by electricity market uncertainty. Finally the report offers recommendations for addressing these limitations and creating a stronger analytical framework for calculating the lifetime cost of nuclear power plants.