In this paper, we consider a risk model in which two types of individual claims, main claims and by-claims, are defined. Every by-claim is induced by the main claim randomly and may be delayed for one time period with...In this paper, we consider a risk model in which two types of individual claims, main claims and by-claims, are defined. Every by-claim is induced by the main claim randomly and may be delayed for one time period with a certain probability. The dividend policy that certain amount of dividends will be paid as long as the surplus is greater than a constant dividend barrier is also introduced into this delayed claims risk model. By means of the probability generating functions, formulae for the expected present value of total dividend payments prior to ruin are obtained for discrete-type individual claims. Explicit expressions for the corresponding results are derived for K n claim amount distributions. Numerical illustrations are also given.展开更多
Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domes...Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domestic hot water） needs. Now days, this technology has resulted as the most viable for exploitation of solar energy, and various countries such as Israel, Turkey, and Greece provide hot water for residential and service sectors using systems of solar panels. In this proceeding we are writing about the dimension of the solar panels surface based to the net present value in Hotels of Albania.展开更多
As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, t...As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, the most scientific and effective method is chain-system differential analysis and the most short-cutting method is the method of net annual value, to select the NA V maximum scheme.展开更多
A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost.Different hydraulic retention times(72-24...A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost.Different hydraulic retention times(72-24 h)were subjected to a flat-sheet membrane bioreactor updated from an existing 72 h oxidation ditch treating antibiotic production wastewater.Field experimental data from the membrane bioreactor,both full-scale(500 m/d)and pilot(1.0 m3/d),were used to calculate the net present value(NPV),incorporating both capital expenditure(CAPEX)and operating expenditure.The results showed that the tank cost was estimated above membrane cost in the 38.2%,where capital expenditure contributed 24.2%more than operational expenditure.Tank construction cost was decisive in determining the net present value contributed 62.1%to the capital expenditure.The membrane bioreactor has the advantage of a longer lifespan flat-sheet membrane,while flux decline was tolerable.The antibiotics decreased to 1.87±0.33 mg/L in the MBR effluent.The upgrade to the membrane bioreactor also benefited further treatments by 10.1%-44.7%lower direct investment.展开更多
The expansion of renewable energy sources(RESs)in European Union countries has given rise to the development of Renewable Energy Communities(RECs),which aremade up of locally generated energy by these RESs controlled ...The expansion of renewable energy sources(RESs)in European Union countries has given rise to the development of Renewable Energy Communities(RECs),which aremade up of locally generated energy by these RESs controlled by individuals,businesses,enterprises,and public administrations.There are several advantages for creating these RECs and participating in them,which include social,environmental,and financial.Nonetheless,according to the Renewable Energy Directive(RED II),the idea of RECs has given opportunities for researchers to investigate the behavior from all aspects.These RECs are characterized by energy fluxes corresponding to self-consumption,energy sales,and energy sharing.Our work focuses on amathematical time-dependentmodel on an hourly basis that considers the optimization of photovoltaic-based RECs tomaximize profit based on the number of prosumers and consumers,as well as the impact of load profiles on the community’s technical and financial aspects usingMATLAB software.In this work,REC’s users can install their plant and become prosumers or vice versa,and users could change their consumption habits until the optimumconfiguration of REC is obtained.Moreover,this work also focuses on the financial analysis of the plant by comparing the Net Present Value(NPV)as a function of plant size,highlighting the advantage of creating a REC.Numerical results have been obtained investigating the case studies of RECs as per the Italian framework,which shows an optimal distribution of prosumers and consumers and an optimal load profile in which the maximum profitability is obtained.Optimization has been performed by considering different load profiles.Moreover,starting from the optimized configurations,an analysis based on the plant size is also made to maximize the NPV.This work has shown positive outcomes and would be helpful for the researchers and stakeholders while designing the RECs.展开更多
This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep we...This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep well with a static water level of 30mand a dynamic level of 50m,serving agricultural and livestock needs.The objective of this study is to accurately size a PV system that balances energy generation and demand while minimizing grid dependency.Meanwhile,the study presents a comprehensivemethodology to calculate flowrates,pumping power,daily energy consumption,and system capacity.Therefore,the PV system rating,energy output,and economic performance were evaluated using metrics such as discounted payback period(DPP),net present value(NPV),and sensitivity analysis.The results show that a 2.74 kWp PV system is optimal,producing 4767 kWh/year to meet the system’s annual energy demand of 4686 kWh.In summer,energy demand peaks at 1532.7 kWh,while in winter,it drops to 692.1 kWh.Meanwhile,flow rates range from 11.71 m^(3)/h at 57 m head to 10.49 m^(3)/h at 70 m head,demonstrating the system’s adaptability to diverse hydraulic conditions.Economic analysis reveals that at a 5%interest rate and an electricity price of$0.15/kWh,the NPV is$6981.82 with a DPP of 3.76 years.However,a 30%increase in electricity prices improves the NPV to$10,005.18 and shortens the DPP to 2.76 years,whereas a 20%interest rate reduces the NPV to$1038.79 and extends the DPP to 6.08 years.Nevertheless,the annual PV energy generation exceeds total energy demand by 81 kWh,reducing grid dependency and lowering electricity costs.Additionally,the PV system avoids approximately 3956.6 kg of CO_(2) emissions annually,underscoring its environmental benefits over traditional pumping systems.As a result,this study highlights the economic and environmental viability of PV-powered water pumping systems,offering actionable insights for sustainable energy solutions in agriculture.展开更多
Using partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit th...Using partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit the existing infrastructure of a hydrocarbon field.Although technical advantages of integrated CO_(2) sequestration and CO_(2)-circulated geothermal harvest using depleted hydrocarbon reservoirs have been reported,quantitative evaluations of economic benefits using existing wells of realistic reservoirs are rare.In this study,a 3-D hydrothermal flow model is built for the Triassic Argilo-Gre seux Supe rieur(TAGS)Formation of the Toual gas field,Algeria using Schlumberger Petrel and CMG-STARS software.A three-phase operational scheme is proposed for sequential CO_(2) sequestration and CO_(2)-circulated geothermal extraction over 100 years.The first phase is injecting CO_(2) for 30 years,followed by concurrent cold CO_(2) injection and hot CO_(2) extraction in the developed CO_(2) plume(circulation)for 40 years as the second phase.In the third phase,producing wells in the second phase are converted to injection wells while outer wells start to extract hot CO_(2) for another 30 years.Scenario 1 is simulated using the selected nine existing wells of the field,while an optimized Scenario 2 is designed and simulated by adding seven newly drilled wells in addition to the existing wells.Scenario 3 shares the same numerical simulation of Scenario 1,but assumes the selected nine existing wells are newly drilled for the economic evaluation.Levelized Cost of Energy(LCOE),Net Present Value(NPV),and Return on Investment(ROI)are used as economic indicators.The results demonstrate that Scenario 2,which combines the use of existing and newly drilled wells,yields improved economic metrics compared to Scenario 1:0.97 USD/MWh vs.1.54 USD/MWh for LCOE and$2.9M vs.$1.1M for NPV.Both scenarios represent profitable endeavors,with ROI values of 1.3%and 1.5%,respectively.In contrast,Scenario 3 represents the worst-case scenario,with the highest LCOE at 2.90 USD/MWh and the lowest NPV and ROI at-$0.4M and-0.2%,respectively.The negative NPV and ROI in Scenario 3 indicates that CO_(2)-circulated geothermal harvesting in aquifers or giant depleted hydrocarbon fields,without leveraging existing infrastructure,is economically infeasible.展开更多
This paper introduces a new approach for measuring shareholder value creation （called adjusted economic profit （EP）） which combines the advantages of both EP and APV （adjusted present value） methods. In particul...This paper introduces a new approach for measuring shareholder value creation （called adjusted economic profit （EP）） which combines the advantages of both EP and APV （adjusted present value） methods. In particular, the shareholder value creation over a period is derived as the sum of two components： the EP relating purely to the operations of the company and the EP generated each period due to the tax benefit that arises from debt financing. We consider our results to be important for analysts and decision makers involved in appraising business performance or making investment decisions and HR professionals as well.展开更多
To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nom...To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nomenclature and architecture are clarified, and assessment criteria are analyzed. The mean and standard deviation of risk adjusted lifecycle cost and net present value （NPV） are defined as assessment metrics. Second, fractionated spacecraft sizing models are briefly described, followed by detailed discussion on risk adjusted lifecycle cost and NPV models. Third, uncertainty sources over fractionated spacecraft life- cycle are analyzed and modeled with probability theory. Then the chronological lifecycle simulation process is expounded, and simulation modules are developed with object oriented methodology to build up the assessment tool. The preceding uncertainty models are integrated in these simulation modules, hence the random object status can be simulated and evolve with lifecycle timeline. A case study to investigate the fractionated spacecraft for a hypothetical earth observation mission is carried out with the proposed assessment tool, and the results show that fractionation degree and launch manifest have great influence on cost and NPV, and generally fractionated spacecraft is more advanced than its monolithic counterpart under uncertainty effect. Finally, some conclusions are given and future research topics are highlighted.展开更多
There are many kinds of real options,which are valuable,in each phase of the lifetime of an information technology(IT)project.However,in the current IT investment decision theory,real options that embedded in IT proje...There are many kinds of real options,which are valuable,in each phase of the lifetime of an information technology(IT)project.However,in the current IT investment decision theory,real options that embedded in IT projects are not considered. In this paper, the process of IT project decision and implementation is fully analyzed, the real options that may be embedded in an IT project are identified, and a real option analysis (ROA) method is proposed for evaluation of an IT project under uncertain business environment. ROA employs Black-Scholes expansion model and cancels the assumption that the cost of project is certain. The numerical example manifests that the ROA can better evaluate IT project and select the IT investment alternative. Finally, a road map is provided to help selecting the suitable evaluation method to make IT investment decision.展开更多
Extensions of Merton’s model(EMM)considering the firm’s payments and generating new types of firm value distribution are suggested.In the open log-value/time space,these distributions evolve from initially normal to...Extensions of Merton’s model(EMM)considering the firm’s payments and generating new types of firm value distribution are suggested.In the open log-value/time space,these distributions evolve from initially normal to negatively skewed ones,and their means are concave-down functions of time.When payments are set to zero or proportional to the firm value,EMM turns into the Geometric Brownian model(GBM).We show that risk-neutral probabilities(RNPs)and the no-arbitraging principle(NAP)follow from GBM.When firm’s payments are considered,RNPs and NAP hold for the entire market for short times only,but for long-term investments,RNPs and NAP just temporarily hold for individual stocks as far as mean year returns of the firms issuing those stocks remain constant,and fail when the mean year returns decline.The developed method is applied to firm valuation to derive continuous-time equations for the firm present value and project NPV.展开更多
Since the implementation of several pilot production tests were in natural gas hydrate(NGH) reservoirs in terrestrial and marine settings, the study of NGH has entered a new stage of technological development for indu...Since the implementation of several pilot production tests were in natural gas hydrate(NGH) reservoirs in terrestrial and marine settings, the study of NGH has entered a new stage of technological development for industrial exploitation. Prior to the industrial exploitation of any given NGH reservoir, the economic feasibility should be examined. The first step of economic evaluation of a NGH reservoir is to know whether its resource amount meets the requirement for industrial exploitation. Unfortunately, few relevant studies have been conducted in this regard. In this study, the net present value(NPV) method is employed to estimate the economic critical resources required for the industrial exploitation of NGHs under different production scenarios. Sensitivity analysis is also performed in order to specify the effects of key factors, such as the number of production wells, gas price, technological improvement and tax incentive, on the economic critical resources. The results indicate that China requires the lowest economic critical resource for a NGH reservoir to be industrially exploited, ranging from 3.62 to 24.02 billion m3 methane. Changes in gas price and tax incentives also play significant roles in affecting the threshold and timeline for the industrial exploitation of NGH.展开更多
An integral connection exists among the mine production planning, the mined material destination, and the ultimate pit limit （UPL） in the mining engineering economy. This relation is reinforced by real information a...An integral connection exists among the mine production planning, the mined material destination, and the ultimate pit limit （UPL） in the mining engineering economy. This relation is reinforced by real information and the benefits it engenders in the mining economy. Hence, it is important to create optimizing algorithms to reduce the errors of economic calculations. In this work, a logical mathematical algorithm that considers the important designing parameters and the mining economy is proposed. This algorithm creates an optimizing repetitive process among different designing constituents and directs them into the maximum amount of the mine economical parameters. This process will produce the highest amount of ores and the highest degree of safety. The modeling produces a new relation between the concept of the cutoff grade, mine designing, and mine planning, and it provides the maximum benefit by calculating the destination of the ores. The proposed algorithm is evaluated in a real case study. The results show that the net present value of the mine production is increased by 3% compared to previous methods of production design and UPL.展开更多
As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has ris...As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios： （1） re-fracturing versus no re- fracturing, （2） combination of re-fracturing and drilling new wells, and （3） time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.展开更多
A dual random model of a portfolio of variable amount whole life annuity is set with the mth moment of the present value of benefits, and the respective expressions of the moments under the assumption that the force o...A dual random model of a portfolio of variable amount whole life annuity is set with the mth moment of the present value of benefits, and the respective expressions of the moments under the assumption that the force of interest accumulation function is Wiener process or Ornstein-Uhlenbeck process. Furthermore, the limiting distribution of average cost of this portfolio is discussed with the expression of the limiting distribution under the assumption that the force of interest accumulation is an independent increment process.展开更多
Reducing emissions due to deforestation is considered a low-cost option for mitigating climate change.However,the recent literature suggests higher opportunity costs because of specific deforestation drivers,which ren...Reducing emissions due to deforestation is considered a low-cost option for mitigating climate change.However,the recent literature suggests higher opportunity costs because of specific deforestation drivers,which render reducing emissions from deforestation and forest degradation(REDD+)for mitigating climate change an uncertain,less attractive,and controversial option.Indonesia is one of the largest greenhouse gas emitters.Since 1989,53.80%of its oil palm expansion has come from forestlands,which has generated a significant amount of carbon emissions.This study uses official data and results from the relevant literature to estimate the costs of oil palm-based deforestation under various scenario assumptions,including different output prices,yields,time horizons,and discount rates.We also calculate the additional cost to preserve a 1-ha forest.We demonstrate that the average opportunity cost from avoiding oil palm-based deforestation is 24.42 USD/tCO_(2)eq in Indonesia,approximately 1.3 times the 2011 EUA carbon price.Additional sums of around 5,466.90–11,042.96 USD/ha should be provided to landowners for the deforestation avoidance caused by oil palm expansion.Special attention should be given to the extensive oil palm expansion in Indonesia and the resulting high opportunity costs for achieving the REDD+target.展开更多
Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,dr...Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.展开更多
Agroforestry and beekeeping are widely promoted as prospective Nature-</span></span><span><span><span style="font-family:""> </span></span></span><span...Agroforestry and beekeeping are widely promoted as prospective Nature-</span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">Based Income Generating Activities (NIGAs) to improve livelihoods while at </span><span style="font-family:Verdana;">the same time enhancing biodiversity conservation in degrading</span><span style="font-family:Verdana;"> agro-ecologies. These activities can diversify and increase famers’ incomes and support in</span><span style="font-family:Verdana;">stinctive biota and fauna resilience. However, evidence to showcase and compare their long-term benefits is scant. We use the case of Uluguru</span><span style="font-family:Verdana;"> Mountains in Tanzania to evaluate and compare viability of agroforestry and beekeeping projects using the Cost</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Benefit Analysis (CBA) approach. The results of analysis yielded positive NPVs for both agroforestry and beekeeping projects at discount rates not higher than 8.2% and 8.5% respectively. Overall, the comparison of economic viability between agroforestry and beekeeping projects revealed that the former was relatively more profitable than the later in terms of both the NPV and Benefit</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Cost Ratio (BCR) criteria. However, the Internal Rate of Return (IRR) for beekeeping was slightly higher than that of agroforestry. Yet, we underscore the fact that these two projects can jointly be implemented to enhance livelihoods of farmers and support biodiversity conservation in the study </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">area </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and other parts with similar agro-ecologies in developing countries. However, farmers in these agro-ecologies need to be supported by governments and non-government development partners in terms of training and inspiration to shift from orthodox farming to sustainable NIGAs.展开更多
基金The NSF (11201217) of Chinathe NSF (20132BAB211010) of Jiangxi Province
文摘In this paper, we consider a risk model in which two types of individual claims, main claims and by-claims, are defined. Every by-claim is induced by the main claim randomly and may be delayed for one time period with a certain probability. The dividend policy that certain amount of dividends will be paid as long as the surplus is greater than a constant dividend barrier is also introduced into this delayed claims risk model. By means of the probability generating functions, formulae for the expected present value of total dividend payments prior to ruin are obtained for discrete-type individual claims. Explicit expressions for the corresponding results are derived for K n claim amount distributions. Numerical illustrations are also given.
文摘Active exploitation of solar energy is achieved in systems that absorb this energy through flat collectors. Hot water can be used for space heating, when its temperature is high, but it is used largely for DHW （domestic hot water） needs. Now days, this technology has resulted as the most viable for exploitation of solar energy, and various countries such as Israel, Turkey, and Greece provide hot water for residential and service sectors using systems of solar panels. In this proceeding we are writing about the dimension of the solar panels surface based to the net present value in Hotels of Albania.
文摘As for the dispute about the best-choosing method of mutually-exclusive scheme and index selection, this text proves that there is an error to make a point that using net present value rate or net annual value rate, the most scientific and effective method is chain-system differential analysis and the most short-cutting method is the method of net annual value, to select the NA V maximum scheme.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFD0501405)National Natural Science Foundation of China(Grant No.21677161)Major Science&Technology Program for Water Pollution Control and Treatment of China(Nos.2017ZX07102-002 and 2018ZX07105-001).
文摘A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost.Different hydraulic retention times(72-24 h)were subjected to a flat-sheet membrane bioreactor updated from an existing 72 h oxidation ditch treating antibiotic production wastewater.Field experimental data from the membrane bioreactor,both full-scale(500 m/d)and pilot(1.0 m3/d),were used to calculate the net present value(NPV),incorporating both capital expenditure(CAPEX)and operating expenditure.The results showed that the tank cost was estimated above membrane cost in the 38.2%,where capital expenditure contributed 24.2%more than operational expenditure.Tank construction cost was decisive in determining the net present value contributed 62.1%to the capital expenditure.The membrane bioreactor has the advantage of a longer lifespan flat-sheet membrane,while flux decline was tolerable.The antibiotics decreased to 1.87±0.33 mg/L in the MBR effluent.The upgrade to the membrane bioreactor also benefited further treatments by 10.1%-44.7%lower direct investment.
文摘The expansion of renewable energy sources(RESs)in European Union countries has given rise to the development of Renewable Energy Communities(RECs),which aremade up of locally generated energy by these RESs controlled by individuals,businesses,enterprises,and public administrations.There are several advantages for creating these RECs and participating in them,which include social,environmental,and financial.Nonetheless,according to the Renewable Energy Directive(RED II),the idea of RECs has given opportunities for researchers to investigate the behavior from all aspects.These RECs are characterized by energy fluxes corresponding to self-consumption,energy sales,and energy sharing.Our work focuses on amathematical time-dependentmodel on an hourly basis that considers the optimization of photovoltaic-based RECs tomaximize profit based on the number of prosumers and consumers,as well as the impact of load profiles on the community’s technical and financial aspects usingMATLAB software.In this work,REC’s users can install their plant and become prosumers or vice versa,and users could change their consumption habits until the optimumconfiguration of REC is obtained.Moreover,this work also focuses on the financial analysis of the plant by comparing the Net Present Value(NPV)as a function of plant size,highlighting the advantage of creating a REC.Numerical results have been obtained investigating the case studies of RECs as per the Italian framework,which shows an optimal distribution of prosumers and consumers and an optimal load profile in which the maximum profitability is obtained.Optimization has been performed by considering different load profiles.Moreover,starting from the optimized configurations,an analysis based on the plant size is also made to maximize the NPV.This work has shown positive outcomes and would be helpful for the researchers and stakeholders while designing the RECs.
文摘This research investigates the design and optimization of a photovoltaic(PV)water pumping system to address seasonal water demands across five locations with varying elevation heads.The systemdraws water froma deep well with a static water level of 30mand a dynamic level of 50m,serving agricultural and livestock needs.The objective of this study is to accurately size a PV system that balances energy generation and demand while minimizing grid dependency.Meanwhile,the study presents a comprehensivemethodology to calculate flowrates,pumping power,daily energy consumption,and system capacity.Therefore,the PV system rating,energy output,and economic performance were evaluated using metrics such as discounted payback period(DPP),net present value(NPV),and sensitivity analysis.The results show that a 2.74 kWp PV system is optimal,producing 4767 kWh/year to meet the system’s annual energy demand of 4686 kWh.In summer,energy demand peaks at 1532.7 kWh,while in winter,it drops to 692.1 kWh.Meanwhile,flow rates range from 11.71 m^(3)/h at 57 m head to 10.49 m^(3)/h at 70 m head,demonstrating the system’s adaptability to diverse hydraulic conditions.Economic analysis reveals that at a 5%interest rate and an electricity price of$0.15/kWh,the NPV is$6981.82 with a DPP of 3.76 years.However,a 30%increase in electricity prices improves the NPV to$10,005.18 and shortens the DPP to 2.76 years,whereas a 20%interest rate reduces the NPV to$1038.79 and extends the DPP to 6.08 years.Nevertheless,the annual PV energy generation exceeds total energy demand by 81 kWh,reducing grid dependency and lowering electricity costs.Additionally,the PV system avoids approximately 3956.6 kg of CO_(2) emissions annually,underscoring its environmental benefits over traditional pumping systems.As a result,this study highlights the economic and environmental viability of PV-powered water pumping systems,offering actionable insights for sustainable energy solutions in agriculture.
基金funded by grants from Sultan Qaboos University(#CL/SQU-IGGCAS/WRC/23/01,#IG/DVC/WRC/24/01)the PRFU project from Larbi Ben M'hidi University-Oum El Bouaghi Algeria(#E04N01UN040120230001)。
文摘Using partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit the existing infrastructure of a hydrocarbon field.Although technical advantages of integrated CO_(2) sequestration and CO_(2)-circulated geothermal harvest using depleted hydrocarbon reservoirs have been reported,quantitative evaluations of economic benefits using existing wells of realistic reservoirs are rare.In this study,a 3-D hydrothermal flow model is built for the Triassic Argilo-Gre seux Supe rieur(TAGS)Formation of the Toual gas field,Algeria using Schlumberger Petrel and CMG-STARS software.A three-phase operational scheme is proposed for sequential CO_(2) sequestration and CO_(2)-circulated geothermal extraction over 100 years.The first phase is injecting CO_(2) for 30 years,followed by concurrent cold CO_(2) injection and hot CO_(2) extraction in the developed CO_(2) plume(circulation)for 40 years as the second phase.In the third phase,producing wells in the second phase are converted to injection wells while outer wells start to extract hot CO_(2) for another 30 years.Scenario 1 is simulated using the selected nine existing wells of the field,while an optimized Scenario 2 is designed and simulated by adding seven newly drilled wells in addition to the existing wells.Scenario 3 shares the same numerical simulation of Scenario 1,but assumes the selected nine existing wells are newly drilled for the economic evaluation.Levelized Cost of Energy(LCOE),Net Present Value(NPV),and Return on Investment(ROI)are used as economic indicators.The results demonstrate that Scenario 2,which combines the use of existing and newly drilled wells,yields improved economic metrics compared to Scenario 1:0.97 USD/MWh vs.1.54 USD/MWh for LCOE and$2.9M vs.$1.1M for NPV.Both scenarios represent profitable endeavors,with ROI values of 1.3%and 1.5%,respectively.In contrast,Scenario 3 represents the worst-case scenario,with the highest LCOE at 2.90 USD/MWh and the lowest NPV and ROI at-$0.4M and-0.2%,respectively.The negative NPV and ROI in Scenario 3 indicates that CO_(2)-circulated geothermal harvesting in aquifers or giant depleted hydrocarbon fields,without leveraging existing infrastructure,is economically infeasible.
文摘This paper introduces a new approach for measuring shareholder value creation （called adjusted economic profit （EP）） which combines the advantages of both EP and APV （adjusted present value） methods. In particular, the shareholder value creation over a period is derived as the sum of two components： the EP relating purely to the operations of the company and the EP generated each period due to the tax benefit that arises from debt financing. We consider our results to be important for analysts and decision makers involved in appraising business performance or making investment decisions and HR professionals as well.
基金Foundation items： National Natural Science Foundation of China （50975280, 61004094） Program for New Century Excellent Talents in University （NCET-08-0149）+1 种基金 Fund of Innovation by Graduate School of National University of Defense Technology （B090102） Hunan Provincial Innovation Foundation for Postgraduate, China.
文摘To comprehensively assess fi＇actionated spacecraft, an assessment tool is developed based on lifecycle simulation under uncertainty driven by modular evolutionary stochastic models. First, fractionated spacecraft nomenclature and architecture are clarified, and assessment criteria are analyzed. The mean and standard deviation of risk adjusted lifecycle cost and net present value （NPV） are defined as assessment metrics. Second, fractionated spacecraft sizing models are briefly described, followed by detailed discussion on risk adjusted lifecycle cost and NPV models. Third, uncertainty sources over fractionated spacecraft life- cycle are analyzed and modeled with probability theory. Then the chronological lifecycle simulation process is expounded, and simulation modules are developed with object oriented methodology to build up the assessment tool. The preceding uncertainty models are integrated in these simulation modules, hence the random object status can be simulated and evolve with lifecycle timeline. A case study to investigate the fractionated spacecraft for a hypothetical earth observation mission is carried out with the proposed assessment tool, and the results show that fractionation degree and launch manifest have great influence on cost and NPV, and generally fractionated spacecraft is more advanced than its monolithic counterpart under uncertainty effect. Finally, some conclusions are given and future research topics are highlighted.
文摘There are many kinds of real options,which are valuable,in each phase of the lifetime of an information technology(IT)project.However,in the current IT investment decision theory,real options that embedded in IT projects are not considered. In this paper, the process of IT project decision and implementation is fully analyzed, the real options that may be embedded in an IT project are identified, and a real option analysis (ROA) method is proposed for evaluation of an IT project under uncertain business environment. ROA employs Black-Scholes expansion model and cancels the assumption that the cost of project is certain. The numerical example manifests that the ROA can better evaluate IT project and select the IT investment alternative. Finally, a road map is provided to help selecting the suitable evaluation method to make IT investment decision.
基金The author is infinitely thankful to his friend and colleague M.Rubinstein for valuable discussions and an invariable interest to his work.The author is also thankful to C.Miller for his high estimation of the author’s efforts.Of course,all errors are author’s full responsibility.
文摘Extensions of Merton’s model(EMM)considering the firm’s payments and generating new types of firm value distribution are suggested.In the open log-value/time space,these distributions evolve from initially normal to negatively skewed ones,and their means are concave-down functions of time.When payments are set to zero or proportional to the firm value,EMM turns into the Geometric Brownian model(GBM).We show that risk-neutral probabilities(RNPs)and the no-arbitraging principle(NAP)follow from GBM.When firm’s payments are considered,RNPs and NAP hold for the entire market for short times only,but for long-term investments,RNPs and NAP just temporarily hold for individual stocks as far as mean year returns of the firms issuing those stocks remain constant,and fail when the mean year returns decline.The developed method is applied to firm valuation to derive continuous-time equations for the firm present value and project NPV.
基金the financial support provided by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030003)supported by the Department of Science and Technology of Guangdong Province,as well as project(DD20221703)supported by the China Geological Survey。
文摘Since the implementation of several pilot production tests were in natural gas hydrate(NGH) reservoirs in terrestrial and marine settings, the study of NGH has entered a new stage of technological development for industrial exploitation. Prior to the industrial exploitation of any given NGH reservoir, the economic feasibility should be examined. The first step of economic evaluation of a NGH reservoir is to know whether its resource amount meets the requirement for industrial exploitation. Unfortunately, few relevant studies have been conducted in this regard. In this study, the net present value(NPV) method is employed to estimate the economic critical resources required for the industrial exploitation of NGHs under different production scenarios. Sensitivity analysis is also performed in order to specify the effects of key factors, such as the number of production wells, gas price, technological improvement and tax incentive, on the economic critical resources. The results indicate that China requires the lowest economic critical resource for a NGH reservoir to be industrially exploited, ranging from 3.62 to 24.02 billion m3 methane. Changes in gas price and tax incentives also play significant roles in affecting the threshold and timeline for the industrial exploitation of NGH.
文摘An integral connection exists among the mine production planning, the mined material destination, and the ultimate pit limit （UPL） in the mining engineering economy. This relation is reinforced by real information and the benefits it engenders in the mining economy. Hence, it is important to create optimizing algorithms to reduce the errors of economic calculations. In this work, a logical mathematical algorithm that considers the important designing parameters and the mining economy is proposed. This algorithm creates an optimizing repetitive process among different designing constituents and directs them into the maximum amount of the mine economical parameters. This process will produce the highest amount of ores and the highest degree of safety. The modeling produces a new relation between the concept of the cutoff grade, mine designing, and mine planning, and it provides the maximum benefit by calculating the destination of the ores. The proposed algorithm is evaluated in a real case study. The results show that the net present value of the mine production is increased by 3% compared to previous methods of production design and UPL.
文摘As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios： （1） re-fracturing versus no re- fracturing, （2） combination of re-fracturing and drilling new wells, and （3） time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.
文摘A dual random model of a portfolio of variable amount whole life annuity is set with the mth moment of the present value of benefits, and the respective expressions of the moments under the assumption that the force of interest accumulation function is Wiener process or Ornstein-Uhlenbeck process. Furthermore, the limiting distribution of average cost of this portfolio is discussed with the expression of the limiting distribution under the assumption that the force of interest accumulation is an independent increment process.
基金supported by the National Natural Science Foundation of China(Program No.72073064)the National Natural Science Foundation of China Youth Science Fund Project(Program No.71703069)+1 种基金the“333 distinguished Talents Project”Foundation of Jiangsu Province in China(Grant No.BRA2018070)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Program No.KYCX20_0876).
文摘Reducing emissions due to deforestation is considered a low-cost option for mitigating climate change.However,the recent literature suggests higher opportunity costs because of specific deforestation drivers,which render reducing emissions from deforestation and forest degradation(REDD+)for mitigating climate change an uncertain,less attractive,and controversial option.Indonesia is one of the largest greenhouse gas emitters.Since 1989,53.80%of its oil palm expansion has come from forestlands,which has generated a significant amount of carbon emissions.This study uses official data and results from the relevant literature to estimate the costs of oil palm-based deforestation under various scenario assumptions,including different output prices,yields,time horizons,and discount rates.We also calculate the additional cost to preserve a 1-ha forest.We demonstrate that the average opportunity cost from avoiding oil palm-based deforestation is 24.42 USD/tCO_(2)eq in Indonesia,approximately 1.3 times the 2011 EUA carbon price.Additional sums of around 5,466.90–11,042.96 USD/ha should be provided to landowners for the deforestation avoidance caused by oil palm expansion.Special attention should be given to the extensive oil palm expansion in Indonesia and the resulting high opportunity costs for achieving the REDD+target.
文摘Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.
文摘Agroforestry and beekeeping are widely promoted as prospective Nature-</span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">Based Income Generating Activities (NIGAs) to improve livelihoods while at </span><span style="font-family:Verdana;">the same time enhancing biodiversity conservation in degrading</span><span style="font-family:Verdana;"> agro-ecologies. These activities can diversify and increase famers’ incomes and support in</span><span style="font-family:Verdana;">stinctive biota and fauna resilience. However, evidence to showcase and compare their long-term benefits is scant. We use the case of Uluguru</span><span style="font-family:Verdana;"> Mountains in Tanzania to evaluate and compare viability of agroforestry and beekeeping projects using the Cost</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Benefit Analysis (CBA) approach. The results of analysis yielded positive NPVs for both agroforestry and beekeeping projects at discount rates not higher than 8.2% and 8.5% respectively. Overall, the comparison of economic viability between agroforestry and beekeeping projects revealed that the former was relatively more profitable than the later in terms of both the NPV and Benefit</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Cost Ratio (BCR) criteria. However, the Internal Rate of Return (IRR) for beekeeping was slightly higher than that of agroforestry. Yet, we underscore the fact that these two projects can jointly be implemented to enhance livelihoods of farmers and support biodiversity conservation in the study </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">area </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and other parts with similar agro-ecologies in developing countries. However, farmers in these agro-ecologies need to be supported by governments and non-government development partners in terms of training and inspiration to shift from orthodox farming to sustainable NIGAs.
