A Decision Advisor to Manage the Implications of Alloy 600 Issues

2003 ◽  
Author(s):  
R. K. Perdue ◽  
C. W. Mycoff ◽  
J. Woodcock ◽  
T. A. Meyer ◽  
R. Llovet
Keyword(s):  
Crack Propagation ◽  
Net Present Value ◽  
Computer Software ◽  
Alloy 600 ◽  
Present Value ◽  
Planning Period ◽  
Software Model ◽  
Plant Operations ◽  
Plant Level ◽  
The Impact

A Decision Advisor process has been designed to efficiently support plant level decisions, and the process has been specialized to support decisions pertaining to plant locations that have alloy 600 degradation issues. The process guides the decision maker through phases of framing the problem, developing options, selecting alternatives, and planning. The decision making process is supported by a computer software model that quantifies the net present value costs of each identified strategy. The Alloy 600 Decision Advisor model calculates crack initiation and growth and the impact on operations and revenue for a given inspection and repair strategy. The three major modules in a component Decision Advisor are: engineering issues of crack propagation and detection, plant operations, and financial impacts. The crack propagation and detection module captures the current state-of-the-art knowledge regarding alloy 600 (and alloy 182/82 for welds) degradation, combining statistical analysis of historical data and expert engineering judgment to produce a forecast of cracks and leaks over the relevant planning period. This is input to the plant operational impact module, which calculates the resulting impacts on plant revenue and cost drivers. The model can be readily updated as new information (such as inspection results) comes available. Results are provided in a report describing the goals and objectives together with the technical and financial input, and providing the plant-level net present value cost of each alternative. The net present value costs include typical costs of implementation (such as inspections and repairs) as well as the effects on power production and plant revenue.

scholarly journals Use of Optimization Modeling to Assess the Effect of Timber and Carbon Pricing on Harvest Scheduling, Carbon Sequestration, and Net Present Value of Eucalyptus Plantations

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 651
Author(s):  
Andrés Hirigoyen ◽  
Mauricio Acuna ◽  
Cecilia Rachid-Casnati ◽  
Jorge Franco ◽  
Rafael Navarro-Cerrillo
Keyword(s):  
Net Present Value ◽  
Programming Model ◽  
C Sequestration ◽  
Mixed Integer ◽  
Harvest Scheduling ◽  
Economic Returns ◽  
Present Value ◽  
Planning Period ◽  
Eucalyptus Dunnii ◽  
The Impact

Quantifying the impact of carbon (C) and timber prices on harvest scheduling and economic returns is essential to define strategies for the sustainable management of short-rotation plantations so that they can provide timber products and contribute to C sequestration. In this paper, we present a mixed-integer linear programming model that optimizes harvest scheduling at the forest level, C sequestration, and Net Present Value (NPV) over a planning period of up to 15 years. The model included revenue from the sale of timber (pulplogs) and credits from the net C sequestered during the life of the stands. In addition, plantation establishment, management, harvesting, and transportation costs were included in the analysis. The study area comprised 88 Eucalyptus grandis W. Hill and Eucalyptus dunnii Maiden stands located in Uruguay, totaling a forest area of nearly 1,882 ha. The study investigated the impact of C and timber prices on NPV, harvest schedules, stands’ harvest age, timber flows to customers, and C sequestered per period. The maximum NPV among all the scenarios evaluated (USD 7.53 M) was calculated for a C price of 30 USD t−1, an interest rate of 6%, and a timber price of 75 USD m−3. This was USD 2.14 M higher than the scenario with the same parameters but that included only revenue from timber. C prices also impacted stands’ harvest age, C sequestration, and timber flows delivered to end customers. On average, in scenarios that included C prices, timber flows and C sequestration increased by 15.4 and 12.1%, respectively, when C price increased from 5 to 30 USD t−1. These results demonstrate that harvest scheduling, harvest age, and NPV are very sensitive to C and timber, and that the best economic returns are obtained when the stands are managed to maximize timber production and C sequestration.

scholarly journals Gas to Liquids Techno-Economics of Associated Natural Gas, Bio Gas, and Landfill Gas

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1568
Author(s):  
Federico Galli ◽  
Jun-Jie Lai ◽  
Jacopo De Tommaso ◽  
Gianluca Pauletto ◽  
Gregory S. Patience
Keyword(s):  
Natural Gas ◽  
Net Present Value ◽  
Landfill Gas ◽  
Labor Cost ◽  
Variable Cost ◽  
Selling Price ◽  
Present Value ◽  
Fischer Tropsch ◽  
Gas To Liquids ◽  
The Impact

Methane is the second highest contributor to the greenhouse effect. Its global warming potential is 37 times that of CO2. Flaring-associated natural gas from remote oil reservoirs is currently the only economical alternative. Gas-to-liquid (GtL) technologies first convert natural gas into syngas, then it into liquids such as methanol, Fischer–Tropsch fuels or dimethyl ether. However, studies on the influence of feedstock composition are sparse, which also poses technical design challenges. Here, we examine the techno-economic analysis of a micro-refinery unit (MRU) that partially oxidizes methane-rich feedstocks and polymerizes the syngas formed via Fischer–Tropsch reaction. We consider three methane-containing waste gases: natural gas, biogas, and landfill gas. The FT fuel selling price is critical for the economy of the unit. A Monte Carlo simulation assesses the influence of the composition on the final product quantity as well as on the capital and operative expenses. The Aspen Plus simulation and Python calculate the net present value and payback time of the MRU for different price scenarios. The CO2 content in biogas and landfill gas limit the CO/H2 ratio to 1.3 and 0.9, respectively, which increases the olefins content of the final product. Compressors are the main source of capital cost while the labor cost represents 20–25% of the variable cost. An analysis of the impact of the plant dimension demonstrated that the higher number represents a favorable business model for this unit. A minimal production of 7,300,000 kg y−1 is required for MRU to have a positive net present value after 10 years when natural gas is the feedstock.

scholarly journals An Analysis of the Effectiveness of Two Rainwater Harvesting Systems Located in Central Eastern Europe

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 458 ◽  
Author(s):  
Agnieszka Stec ◽  
Martina Zeleňáková
Keyword(s):  
Sensitivity Analysis ◽  
Net Present Value ◽  
Rainwater Harvesting ◽  
Payback Period ◽  
Practical Aspect ◽  
Financial Ratios ◽  
Present Value ◽  
Toilet Flushing ◽  
Harvesting Systems ◽  
The Impact

Decentralized water systems are perceived as solutions that not only save water, but also as a way to partially or completely become independent from centralized suppliers. Taking this into account, an analysis of the effectiveness of rainwater harvesting systems (RWHS) for toilet flushing in existing academic facilities located in Poland and in Slovakia was carried out. The tests took into account the different volumes of storage tanks collecting rainwater. On the basis of two financial ratios, namely Net Present Value and Discounted Payback Period, the profitability of these systems was also assessed. The research was extended by the sensitivity analysis, which allowed determination of the impact of changes in individual cost components on the financial effectiveness of the investments considered. The results obtained clearly showed that the implementation of RWHS in the dormitory in Rzeszów was unprofitable for all tank capacities tested, and the payback period significantly exceeded the period of 30 years accepted for the analysis. Completely different results were obtained for RWHS in a dormitory located in the city of Košice, for which the financial ratios NPV (Net Present Value) and DPP (Discounted Payback Period) were very favorable. It was also confirmed by the results of the sensitivity analysis. The use of rainwater for toilet flushing caused that it was possible to achieve water savings of an average of 29% and 18%, respectively, for facilities located in Slovakia and Poland. The results of the research have a practical aspect and can provide an indication for potential investors and managers of academic facilities, similar to those analyzed in the article. Taking into account that in many countries water and sewage rates are significantly higher than in Poland and Slovakia, the cost-effectiveness of using the analyzed installation options in these countries could be even higher.

A dynamic programming algorithm for optimization of uneven-aged forest stands

1994 ◽  
Vol 24 (9) ◽  
pp. 1758-1765 ◽  
Author(s):  
David J. Anderson ◽  
B. Bruce Bare
Keyword(s):  
Dynamic Programming ◽  
Interest Rates ◽  
Net Present Value ◽  
Initial Conditions ◽  
Dynamic Programming Algorithm ◽  
Basal Area ◽  
Management Problem ◽  
Present Value ◽  
Stand Management ◽  
The Impact

A deterministic dynamic programming formulation of the transition uneven-aged stand management problem is presented. Using a previously published northern hardwoods growth model, a forward recursive, discrete, two-state problem that maximizes the net present value of harvested trees at each stage is developed. State variables represent the total number of trees and the total basal area per acre. A neighborhood storage concept previously published is used to reduce the number of states considered at each stage. Two harvest allocation rules are used to assign the harvested basal area to individual diameter classes. Terminal end point conditions and stage to stage sustainability are not required. Results from four base runs of the model are presented and compared with previously published results. Each run produces significantly different optimal paths, with one showing a higher net present value than any previously published. Sensitivity runs illustrate the impact of changes in interest rates, width of neighborhood storage class, and initial conditions. Dynamic programming offers promise for analyzing uneven-aged stand management problems.

scholarly journals Assessment of the Nutritional Impact of Agricultural Research: The Case of Mungbean in Pakistan

2005 ◽  
Vol 26 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Katinka Weinberger
Keyword(s):  
Net Present Value ◽  
Agricultural Research ◽  
Low Cost ◽  
Secondary Data ◽  
Marginal Effect ◽  
Micronutrient Deficiencies ◽  
Iron Intake ◽  
Present Value ◽  
Piece Rate ◽  
The Impact

Background Evaluation of agricultural research often neglects consumption and nutrition aspects. Yet agricultural research can address micronutrient malnutrition by improving both quantity and quality of food intake. Objective To briefly review the conceptual linkages between agriculture and nutrition, to estimate the strength of the relationship between iron intake and productivity outcomes, and to estimate the nutritional benefit of improved mungbean varieties in terms of net present value. This paper presents a methodology for assessing the nutritional impact of mungbean, and summarizes current impact evidence on the path from mungbean research to consumption. Methods A consumption study was conducted among female piece-rate workers in Pakistan to analyze the impact of iron consumption on productivity, measured in wages. A two-stage least-squares analysis was used to estimate the elasticity of iron intake on wages. The results derived from this study were extrapolated to country level using secondary data sources. Results We found that anemia among women was widespread. Approximately two-thirds of women suffered from mild or severe anemia (Hb < 12 g/dL). We found the elasticity of bioavailable iron on productivity measured in wages was 0.056, and the marginal effect was 9.17 Pakistani rupees per additional mg of bioavailable iron consumed. Using the model results we estimated the impact of mungbean research on nutrition, in terms of productivity effects, and found it was substantial, ranging from US$7.6 to 10.1 million cumulative present value (in 1995 US$ at 5% discount rate). Conclusions Agriculture certainly plays an important role in the reduction of malnutrition. Agricultural research has greatly contributed to the reduction of hunger and starvation by providing millions of hungry people with access to low-cost staple foods. Now, as the challenge shifts to the reduction of micronutrient deficiencies, more efforts must be directed toward crops high in micronutrients, such as pulses and vegetables.

SYLVER: Modelling the Impact of Silviculture on Yield, Lumber Value, and Economic Return

1988 ◽  
Vol 64 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Kenneth J. Mitchell
Keyword(s):  
Net Present Value ◽  
Financial Analysis ◽  
Wood Properties ◽  
Growth And Yield ◽  
Present Value ◽  
Silvicultural Treatments ◽  
Intensive Forest Management ◽  
Product Value ◽  
Analysis System ◽  
The Impact

Intensive forest management requires an understanding of the effect that silvicultural treatments have on wood properties, standing yield, log quality, product value, and net present value. These needs are addressed by a system of models (SYLVER) which includes the Tree and Stand Simulator (TASS), Root Rot Simulator (ROTSIM), Sawmill Simulator (SAWSIM), and the new Financial Analysis System (FAN$Y). The latter will be used by field foresters to compare the merits of candidate treatments for specific stands. Key words: Silviculture, growth and yield, juvenile wood, log quality, end-product value, net present value, Pseudotsuga menziesii, Phellinus weirii, modelling, TASS, ROTSIM, SAWSIM, FAN$Y, SYLVER.

scholarly journals An Application of Linear Programming for Short-Term Harvest Scheduling

1988 ◽  
Vol 5 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Douglas C. Macmillan ◽  
Stephen E. Fairweather
Keyword(s):  
Linear Programming ◽  
Net Present Value ◽  
Harvest Scheduling ◽  
Present Value ◽  
Short Term ◽  
Planning Period ◽  
Additional Information ◽  
Forest Ownership ◽  
Forest Enterprises ◽  
High Level

Abstract The technique of linear programming (LP) is illustrated by developing a harvest schedule for an industrial forest ownership in northwestern Pennsylvania. The objective was to maximize net present value of the harvest over a five-year planning period. The effect of changes in timber value and growth rate on the optimum schedule was determined. Sensitivity analysis provided additional information the manager could use to make decisions. In order to successfully apply LP, the forester must be able to define the management objective of the harvest schedule and the resource and managerial constraints that will influence its attainment. Data used in the model have to be available and reliable. Many forest enterprises should be in the position to adopt LP since commercial programs for microcomputers are now available for which a high level of computing expertise is not required. North. J. Appl. For. 5:145-148, June 1988.

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