Cost Assumptions Research Articles

Assessment of the Role of CCS in the Provision of Long-Term Security of Power Supply and Deep CO2 Emission Reduction

In order to study cost-optimal power systems consistent with the Paris agreement, a model of the Western-European power system was developed. The model includes a wide range of renewable and non-renewable technology options, assumptions on future techno-economic parameters and demand. Examining the effect of more ambitious emissions targets (net zero to -3.2 Gt CO2 yr-1), it is found that based on cost optimization with base case cost assumptions, bioenergy with CO2 capture and storage and nuclear power generation both play significant roles. Once the available domestic biomass potential is fully exploited for bio energy with carbon capture and storage (up to 5.9 EJ yr-1), direct air capture of CO2 combined with nuclear power as baseload is needed for further negative emissions. With deeper emission reduction targets, the installed capacity of intermittent renewable energy sources like wind and solar photovoltaics decreases as CO2-neutral generation does not deliver the required negative emissions. Finally, it is found that portfolios relying on intermittent renewable energy sources are vulnerable to unfavourable weather conditions, resulting in higher net CO2 emissions and a less reliable power supply.

Optimization of reinforcement steel supply to precast concrete plants

In addition to aggregates, cement, and water, reinforcing steel is one of the key building components of precast products. Steel price fluctuations observed on global markets have a large impact on the cost of production of precast products made of reinforced and prestressed concrete. An important issue is, therefore, the proper planning of steel orders and deliveries to the precast concrete plants. A significant number of competing warehouses and construction warehouses offer diversified steel prices, which are subject to frequent changes in relatively short periods. This results in a problem in the selection of an appropriate procurement strategy by precast concrete plants. An additional unfavorable factor is the ordering of reinforcing steel that is too large in relation to the demands of the precast concrete plants, resulting in high costs of its storage in the warehouses or storage yards. In this paper, the issues of optimal planning and delivery of plain, ribbed, and prestressing steel were discussed. For the research and calculation purposes, supplies of steel from four wholesalers to four different precast concrete plants were assumed. In addition, the types of steel and the class of bars used to reinforce the elements were discussed. A different level of unit prices for the purchase and delivery of steel in each warehouse and a different demand for each of the four concrete plants were also assumed. As a result of the analyses carried out, a model was developed, including the strategy of purchasing and supplying plain, ribbed, and prestressing steel with the assumption of minimum costs.

The Cost-Effectiveness of Interventions to Increase Utilization of Prone Positioning for Severe Acute Respiratory Distress Syndrome.

Despite strong evidence supporting proning in acute respiratory distress syndrome, few eligible patients receive it. This study determines the cost-effectiveness of interventions to increase utilization of proning for severe acute respiratory distress syndrome. We created decision trees to model severe acute respiratory distress syndrome from ICU admission through death (societal perspective) and hospital discharge (hospital perspective). We assumed patients received low tidal volume ventilation. We used short-term outcome estimates from the PROSEVA trial and longitudinal cost and benefit data from cohort studies. In probabilistic sensitivity analyses, we used distributions for each input that included the fifth to 95th percentile of its CI. ICUs that care for patients with acute respiratory distress syndrome. Patients with moderate to severe acute respiratory distress syndrome. The implementation of a hypothetical intervention to increase the appropriate utilization of prone positioning. In the societal perspective model, an intervention that increased proning utilization from 16% to 65% yielded an additional 0.779 (95% CI, 0.088-1.714) quality-adjusted life years at an additional long-term cost of $31,156 (95% CI, -$158 to $92,179) (incremental cost-effectiveness ratio = $38,648 per quality-adjusted life year [95% CI, $1,695-$98,522]). If society was willing to pay $100,000 per quality-adjusted life year, any intervention costing less than $51,328 per patient with moderate to severe acute respiratory distress syndrome would represent good value. From a hospital perspective, the intervention yielded 0.072 (95% CI, 0.008-0.147) more survivals-to-discharge at a cost of $5,242 (95% CI, -$19,035 to $41,019) (incremental cost-effectiveness ratio = $44,615 per extra survival [95% CI, -$250,912 to $558,222]). If hospitals were willing to pay $100,000 per survival-to-discharge, any intervention costing less than $5,140 per patient would represent good value. Interventions that increase utilization of proning would be cost-effective from both societal and hospital perspectives under many plausible cost and benefit assumptions.

Robust Non-Rigid Motion Compensation of Free-Breathing Myocardial Perfusion MRI Data.

Kinetic parameter values, such as myocardial perfusion, can be quantified from dynamic contrast-enhanced magnetic resonance imaging data using tracer-kinetic modeling. However, respiratory motion affects the accuracy of this process. Motion compensation of the image series is difficult due to the rapid local signal enhancement caused by the passing of the gadolinium-based contrast agent. This contrast enhancement invalidates the assumptions of the (global) cost functions traditionally used in intensity-based registrations. The algorithms are unable to distinguish whether the differences in signal intensity between frames are caused by the spatial motion artifacts or the local contrast enhancement. In order to address this problem, a fully automated motion compensation scheme is proposed, which consists of two stages. The first of which uses robust principal component analysis (PCA) to separate the local signal enhancement from the baseline signal, before a refinement stage which uses the traditional PCA to construct a synthetic reference series that is free from motion but preserves the signal enhancement. Validation is performed on 18 subjects acquired in free-breathing and 5 clinical subjects acquired with a breath-hold. The validation assesses the visual quality, the temporal smoothness of tissue curves, and the clinically relevant quantitative perfusion values. The expert observers score the visual quality increased by a mean of 1.58/5 after motion compensation and improvement over the previously published methods. The proposed motion compensation scheme also leads to the improved quantitative performance of motion compensated free-breathing image series [30% reduction in the coefficient of variation across quantitative perfusion maps and 53% reduction in temporal variations (p < 0.001)].

Infrastructure Sharing Synergies and Industrial Symbiosis: Optimal Capacity Oversizing and Pricing

In this paper we show that Industrial Symbiosis (IS) being implemented in Eco-Industrial Parks (EIP) deals with both substitution synergies (exchange of waste materials, fatal energy and/or utilities as resources for production) and infrastructure/service sharing synergies. The latter is based on the intensification of use of an asset and thus requires to balance capital costs increase with economies of scale for its implementation. Initial investors must specify ex-ante arrangements (cost sharing and pricing schedule) to commit toward investments in infrastructure capacity and the associated transactions. In this way we propose a model that investigates the decision of 3 actors, 2 trying to choose cooperatively a level of infrastructure capacity oversizing to set a plug-and-play offer to 1 potential entrant. The latter has a capacity requirement which is randomly distributed. Capacity cost exhibits sub-additive property so that there is room for profitable overcapacity setting. The entrant's willingness-to-pay for the access to the infrastructure depends on its standalone cost and the capacity gap that must be completed in case the available capacity is insufficient ex-post (the backup cost). Since initial capacity choices are driven by the ex-ante (expected) entrant's willingness-to-pay we derive the expected complement cost function which helps us to define the investor's objective function. We first show that this curve is decreasing and convex in the capacity increments and that it is shaped by the distribution function of the potential entrant's requirements. We then derive the general form of solutions and solve the model for uniform distribution. Depending on the requirements volumes and the cost assumptions different capacity levels are set.

Mutational load causes stochastic evolutionary outcomes in acute RNA viral infection.

Mutational load is known to be of importance for the evolution of RNA viruses, the combination of a high mutation rate and large population size leading to an accumulation of deleterious mutations. However, while the effects of mutational load on global viral populations have been considered, its quantitative effects at the within-host scale of infection are less well understood. We here show that even on the rapid timescale of acute disease, mutational load has an effect on within-host viral adaptation, reducing the effective selection acting upon beneficial variants by ∼10 per cent. Furthermore, mutational load induces considerable stochasticity in the pattern of evolution, causing a more than five-fold uncertainty in the effective fitness of a transmitted beneficial variant. Our work aims to bridge the gap between classic models from population genetic theory and the biology of viral infection. In an advance on some previous models of mutational load, we replace the assumption of a constant variant fitness cost with an experimentally-derived distribution of fitness effects. Expanding previous frameworks for evolutionary simulation, we introduce the Wright-Fisher model with continuous mutation, which describes a continuum of possible modes of replication within a cell. Our results advance our understanding of adaptation in the context of strong selection and a high mutation rate. Despite viral populations having large absolute sizes, critical events in viral adaptation, including antigenic drift and the onset of drug resistance, arise through stochastic evolutionary processes.

Buzzwords Build Momentum: Global Financial Twitter Sentiment and the Aggregate Stock Market

We examine the long-term relationship between signals derived from nine years of unstructured social media microblog text data and financial market developments in five major economic regions. Employing statistical language modeling techniques we construct directional sentiment metrics and link these to aggregate stock index returns. To address the noise in finance-related Twitter messages we identify expert users whose tweets predominantly focus on finance topics. We document that expert users are the main drivers behind a significant contemporaneous link between Twitter sentiment and financial markets. Notably, the link remains equally strong in times of major news events impacting the markets. The direct prediction value of expert sentiment metrics for stock index returns, however, is found to be elusive and short-lived. Yet, the relation between expert sentiment metrics and stock indices is sufficient to devise profitable cross-sectional as well as time series momentum investment strategies based on Twitter signals that survive basic transaction cost assumptions. In this context, our results show that expert sentiment signals can yield higher risk-adjusted returns than classical price-signals.

Political budget cycles, incumbency advantage, and propaganda

AbstractThis paper combines incumbency advantage and political budget cycle theory. An opportunistic politician is given two instruments: deficit‐financed transfers and propaganda. Unlike earlier analytical models, but in accordance with the empirical literature, government manipulations do actually improve re‐election chances. However, the optimal level of government manipulation depends on country characteristics, in particular the competence dispersion among potential candidates. This may explain why it is easier to detect political budget cycles in, for instance, developing countries or new democracies. Results are robust to alternative competence distribution and propaganda cost assumptions.

Energy Consumption and Life Cycle Costs of Overhead Catenary Heavy-Duty Trucks for Long-Haul Transportation

The overhead catenary truck is an interesting technology for long-haul transportation with heavy-duty trucks because it can combine the advantage of energy supply via catenary while driving and the flexibility of a battery truck on routes without catenary using the traction battery. This study investigates the energy consumptions of overhead catenary trucks on German highways and considers different configurations for the traction battery and catenary power system. Afterwards the life cycle costs of overhead catenary trucks are calculated for a specified long-haul transportation scenario and the results are compared to battery electric truck and diesel truck using the findings of a previous study by the authors. The energy consumption of the considered overhead catenary trucks is approximately equal to that of a battery electric truck but only about a half of the equivalent energy consumption of a conventional diesel truck. According to the cost assumptions in this study, the total life cycle costs of overhead catenary trucks can be in the range of the conventional diesel truck, showing the competitiveness of this alternative truck technology.

Proximal Dynamics in Multiagent Network Games

We consider dynamics and protocols for agents seeking an equilibrium in a network game with proximal quadratic cost coupling. We adopt an operator-theoretic perspective to show global convergence to a network equilibrium, under the assumption of convex cost functions with proximal quadratic couplings, time-invariant and time-varying communication graph along with convex local constraints, and a time-invariant communication graph along with convex local constraints and separable convex coupling constraints. We show that proximal dynamics generalize opinion dynamics in social networks and are applicable to distributed tertiary control in power networks.

Direct quantification of multiple-source energy flexibility in a residential building using a new model predictive high-level controller

This article presents a new energy management system (EMS) for a variety of energy flexibility conversion, routing and storage options in buildings. The EMS uses an efficient nonlinear optimization-based model-predictive control (MPC) method, which achieves low computational complexity by utilizing successive linear programming (SLP) for continuous approximations of discrete (two-level) control problems. Whole-year simulation runs demonstrate that the method is applicable to a residential building system that has multiple energy generation, conversion and storage units with significant nonlinear interactions. Both qualitative and quantitative comparison of the simulation results with a rule-based reference control showed strong dependencies between cost and CO2 emission flexibility goals, energy selling prices and forecasting accuracy. This study shows that significant cost savings can be obtained by taking advantage of energy price fluctuations, increasing the average coefficient of performance (COP) of the heating system, and reducing passive losses in heat storage. In the simulated case study the EMS was able to improve the average COP of a heating system from 2.20 to 2.43–2.74, depending on energy cost assumptions, when compared against a rule-based control (RBC). With a performance bound of perfect forecasting the EMS was able to improve net economic outcome by 38–168%, or by 21–75% of the cost of imported electricity.

Implications of Alternative Land Conversion Cost Specifications on Projected Afforestation Potential in the United States.

The Forestry and Agriculture Sector Optimization Model with Greenhouse Gases (FASOMGHG) has historically relied on regional average costs of land conversion to simulate land use change across cropland, pasture, rangeland, and forestry. This assumption limits the accuracy of the land conversion estimates by not recognizing spatial heterogeneity in land quality and conversion costs. Using data from Nielsen et al. (2014), we obtained the afforestation cost per county, then estimated nonparametric regional marginal cost functions for land converting to forestry. These afforestation costs were then incorporated into FASOMGHG. Three different assumptions for land moving into the forest sector (constant average conversion cost, static rising marginal costs, and dynamic rising marginal cost) were run in order to assess the implications of alternative land conversion cost assumptions on key outcomes, such as projected forest area and cropland use, carbon sequestration, and forest product output.

Population growth: A pure welfarist approach

In this study we propose a framework based on welfarist principles to deal with several issues concerned with population economics models, such as the Repugnant Conclusion, both in absolute and relative sense, the shape of childbearing costs and population dynamics, under both normative and positive perspectives. We show that the relative critical level criterion can avoid both the assumption of high childbearing costs and the absolute repugnant conclusion (ARC) but cannot avoid the relative repugnant conclusion (RRC). Moreover, optimal fertility is increased by technological shocks and displays cycles. Both ARC and RRC can be avoided by extending the model to a decentralized economy with consumption externalities; in the latter model, a technological shock reduces long‐run fertility and can generate cycles along the transitional path.

Cost sensitivity of optimal sector-coupled district heating production systems

Goals to reduce carbon emissions and changing electricity prices due to increasing penetrations of wind power generation affect the planning and operation of district heating production systems. Through extensive multivariate sensitivity analysis, this study estimates the robustness of future cost-optimal heat production systems under changing electricity prices, fuel cost and investment cost. Optimal production capacities are installed choosing from a range of well-established production and storage technologies including boilers, combined heat and power (CHP) units, power-to-heat technologies and heat storages. The optimal heat production system is characterized in three different electricity pricing scenarios: Historical, wind power dominated and demand dominated. Coal CHP, large heat pumps and heat storages dominate the optimal system if fossil fuels are allowed. Heat pumps and storages take over if fossil fuels are excluded. The capacity allocation between CHP and heat pumps is highly dependent on cost assumptions in the fossil fuel scenario, but the optimal capacities become much more robust if fossil fuels are not included. System cost becomes less robust in a fossil free scenario. If the electricity pricing is dominated by wind power generation or by the electricity demand, heat pumps become more favorable compared to cogeneration units. The need for heat storage more than doubles, if fossil fuels are not included, as the heating system becomes more closely coupled to the electricity system.

The Inclusion of Ecosystem Service Valuations in Bioenergy Cost Analysis: A Case Study of Constructed Wetlands in the Neotropics

From an ecosystem services perspective, wetlands are among the most valuable ecosystems per unit area on earth. Here, we investigate the ability of a constructed wetland to provide two ecosystem services – biomass for bioenergy and wastewater treatment – using Costa Rica as a case study for a Neotropical developing world context. In the absence of wastewater treatment ecosystem services, biomass production costs are expected to range from 243 to 1287 $ dry Mg−1 depending on model assumptions. When ecosystem services are valued based on a contingent valuation method and given optimistic capital cost assumptions, the costs of biomass production range from 38 to −290 $ dry Mg−1. Negative costs indicate income and suggest that under certain assumptions, the value of water treatment services is large enough to pay for wetland operations, and that biomass can be provisioned for free while still maintaining system profitability. The analysis suggests that the valuation of multiple ecosystem services may alter the economic sustainability of some biomass for bioenergy production systems.

Intraoperative Margin Assessment by Frozen Section Enables Cost-Effective, Safe, One-Step Breast Conservation

Purpose Acceptance of breast conservation surgery (BCS) is low among Indian women, as many perceive mastectomy to be a superior cost-effective surgical option. Obtaining uninfiltrated margins is vital during BCS. The need for reoperation to re-excise infiltrated surgical margins adds to the cost of treatment, which further reduces the acceptability of BCS. Intraoperative frozen-section (FS) histology assessment of margins provides an opportunity to carry out a single-stage, safe BCS; however, the utility of FS margin assessment remains unproven because of its perceived low accuracy, added costs, and longer operating time. In this retrospective analysis, we studied the accuracy of FS for margin assessment, its ability to help avoid reoperations, and the cost effectiveness of one-step BCS using FS compared with margin assessment using postoperative paraffin section (PS) histopathology. Methods Patients who underwent BCS during 2011 to 2015 with a minimum 1-year follow-up were included. All patients underwent intraoperative FS and postoperative PS margin assessment. All infiltrated margins were re-excised. Repeatedly infiltrated re-excised margins or extensive ductal carcinoma in situ necessitated mastectomy in few patients. We evaluated the accuracy of FS in the detection of margin infiltration, thereby allowing single-stage, safe BCS. The cost effectiveness of two strategies for the management of infiltrated margins, namely intraoperative FS and single-stage margin excision/mastectomy and postoperative PS and reoperation (two-step) surgery, were compared. The cost per saved reoperation with the use of intraoperative FS was calculated using actual hospital costs and various—lower and higher—cost assumptions. Results On the basis of intraoperative FS margin assessment, 18 (12.5%) of 144 patients required margin(s) re-excision and another nine patients (6.2%) needed mastectomy. Twenty-six patients (18%) were thus spared reoperation with the use of FS. Two patients (1.4%) with uninfiltrated margins on FS—false-negative FS—needed reoperation for infiltrated margins that were detected on PS. Considering the costs (144 FS and two reoperations) and savings (26 avoided reoperations), use of FS was 1.15 times more cost effective than PS for achieving uninfiltrated margins. Cost incurred per saved reoperation by FS was INR 5,438 (approximately $81 USD). Sensitivity analysis using various cost assumptions revealed similar results. Conclusion Use of FS can facilitate single-step, oncologically safe BCS by avoiding reoperation in those patients with infiltrated margins and is cost effective compared with postoperative margin assessment using PS alone. FS can thus help in improving the acceptability of BCS, even in those patients with relatively large tumors for whom the possible need and cost of reoperation are major deterrents against BCS. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The following represents disclosure information provided by authors of this manuscript. All relationships are considered compensated. Relationships are self-held unless noted. I = Immediate Family Member, Inst = My Institution. Relationships may not relate to the subject matter of this manuscript. For more information about ASCO's conflict of interest policy, please refer to www.asco.org/rwc or ascopubs.org/jco/site/ifc . No COIs from the authors.

Combining choice modeling estimates and stochastic simulations to assess the potential of new crops—The case of lignocellulosic perennials in Southwestern Germany

AbstractIn the future, the lignocellulosic perennial crops short rotation coppice (SRC) and miscanthus are supposed to provide renewable raw materials for a bio‐based economy. To assess the potential regional supply of these crops, which are not yet widespread in Baden–Wuerttemberg (Southwest Germany), we used a two‐step approach. In a first step, we conducted a Discrete Choice Experiment (DCE) in regions of Baden–Wuerttemberg that—given their site conditions—are suitable for SRC or miscanthus. The respondents were characterized by significant preference heterogeneity for both (negatively valued) perennial crops and for all presented choice attributes. Thus, it was appropriate to estimate a random parameter logit model (RPL). The attributes average yearly contribution margin, long‐term purchase guarantee and cultivation by colleagues in the neighborhood had a significantly positive effect on the likelihood of cultivation, whereas the attributes contribution margin variability and initial investment need showed a significantly negative effect. In a second step, assuming realistic values for the levels of the attributes considered in the DCE, in stochastic simulations, we randomly draw part‐worth utilities from the multivariate normal distribution of these parameters according to the RPL results. This way, for alternative biomass prices, we derived shares of farmers’ willing to engage in perennial crop production and produced related regional supply functions. Under moderate yield and realistic input and farmland opportunity cost assumptions, the full regional miscanthus potential can only be achieved when farmers are offered either subsidies or price‐risk‐reducing long‐term contracts. Based on empirically determined heterogeneous farmer preferences, our two‐step approach is suitable to yield realistic estimations of any not yet implemented farming practices. We finally note caveats related to our analysis and discuss some policy implications of the major findings.

The cost of addressing saline lake level decline and the potential for water conservation markets

The world's saline lakes are shrinking and human water diversions are a significant contributor. While there is increased interest in protecting the ecosystem services provided by these lakes, the cost of protecting water levels has not been estimated. To explore this question we consider the case of Great Salt Lake (Utah, USA) where human diversions from three rivers have caused the lake level to decline during the last century. Recent work has suggested the restoration of inflows is necessary to maintain a target elevation consistent with well-functioning ecosystems. We construct cost estimates of increasing water inflows using conservation cost curves for each river basin. We then compare the cost of uniform cutbacks to cap-and-trade systems which allow intra- and inter-basin trading. The cost of water to permanently implement uniform water right cutbacks to increase inflows by 20% above current levels is $37.4 million. Costs and cost-savings are sensitive to alternative allocation, inflow, and cost assumptions, and we estimate significant cost reductions from intra-basin water conservation markets (5–54% cost decrease) and inter-basin water conservation markets (22–57% cost decrease).

A systematic approach to offshore wind turbine jacket predesign and optimization: geometry, cost, and surrogate structural code check models

Abstract. The main obstacles in preliminary design studies or optimization of jacket substructures for offshore wind turbines are high numerical expenses for structural code checks and simplistic cost assumptions. In order to create a basis for fast design evaluations, this work provides the following: first, a jacket model is proposed that covers topology and tube sizing with a limited set of design variables. Second, a cost model is proposed that goes beyond the simple and common mass-dependent approach. And third, the issue of numerical efficiency is addressed by surrogate models for both fatigue and ultimate limit state code checks. In addition, this work shows an example utilizing all models. The outcome can be utilized for preliminary design studies and jacket optimization schemes. It is suitable for scientific and industrial applications.

Environmental instrument choice in a non-linear world

ABSTRACTThe substantial literature on environmental instrument choice under uncertainty has provided valuable insights using simplifying assumptions of linear marginal cost and benefit curves and additive error terms to determine when and why a price or quantity instrument should be preferred. But empirical analysis has shown that linearity and additivity are not the norm. This paper explores the formal properties of instrument choice when the marginal benefit and marginal cost curves are non-linear; the error term is multiplicative and assumed to be exponential; and the choice is expanded to include comparisons among different price and different quantity regimes, as well as choices between these types. In this more realistic environment, we show that small changes in variance and parameter values can have a significant impact on optimal instrument choices.