Diverse Fleet Research Articles

Evaluating the impact of third-party price reporting and other drivers on residential photovoltaic price estimates

AimPolicy-makers typically track the rapidly evolving U.S. residential photovoltaic (PV) market by relying on price data reported by PV installers/integrators to incentive programs. Recent years have witnessed a shift toward third-party-owned (TPO) business models, in which the absence of a cash purchase price obscures data interpretation. Appraisals—often based on estimates of the average fair market value across a diverse fleet of systems—are one way TPO prices are reported. ScopeThis study investigates residential PV system price drivers to improve the accuracy, consistency, and relevance of PV price-tracking efforts. Our econometric approach evaluates system price drivers using California Solar Initiative data, controlling for system, installer, and geographic variables. ConclusionsWe find that reported prices for confirmed appraised systems are $1.13/W higher than non-appraised systems and do not respond to hypothesized price drivers. For non-appraised systems, we find preliminary evidence of market distortions based on the impact of the incentive level, module cost and household income on reported price. Further, unspecified installer heterogeneity—possibly due to differences in products, cost structure or reporting practices—is a substantial price driver. Using estimates, we develop a price model to approximate non-appraised system prices.

The flexibility and benefits of operating a diverse fleet: an analysis using real options

PurposeThe purpose of this paper is to develop a simple model illustrating the benefits of operating a diverse fleet of aircraft.Design/methodology/approachThe paper is theoretical. It describes how real options are beneficial to the firm in both capital budgeting and risk management. It illustrates the use of real options in the airline industry, and how real options are used as a risk management tool. Then the model is developed which illustrates how a diverse fleet can provide an airline protection against fuel price risk.FindingsThe results of the model show that a diverse fleet is value enhancing to an airline during periods when fuel prices are high or uncertain. Furthermore, this paper shows that a diverse fleet provides an airline with an operational hedge to jet fuel prices. Though the paper focuses on the airline industry, the results are applicable to those industries vulnerable to volatile input costs, and prohibitive abandonment and re‐entry costs.Originality/valueThe paper uses real option analysis to show the benefits for an airline deriving from operating a diverse fleet of aircraft.

Global Plutonium Production Capabilities with Civilian Research Reactors

This article deals with the plutonium production capabilities in civilian research reactors and the resulting proliferation risks. A complete record of all civilian research reactors located in Non-Nuclear Weapon States and de-facto Nuclear Weapon States is compiled and systematized according to their type. A discussion of the various production paths and scenarios for plutonium with those reactors follows. In order to derive an assessment with a broad coverage, partly diverse fleet of reactors, two designs representative of light water and heavy water moderated reactors (which account for 82 percent of the total installed capacity in Non-Nuclear Weapon States and de-facto Nuclear Weapon States) were chosen and included in burn-up calculations with the Monte Carlo code KENO V.a and Origen-S, both incorporated in the modular system Scale-6. The effective production rates in fuel elements as well as by irradiation of targets are then applied to calculate the capabilities of plutonium production of each considered research reactor. The results provide an overview of the proliferation relevance of the global research reactor fleet and its regional distribution.

Quantification of Over-Speed Risk in Wind Turbine Fleets

The effective life management of large and diverse fleets of wind turbines is a new problem facing power system utilities. More specifically, the minimization of over-speed risk is of high importance due to the related impacts of possible loss of life and economic implications of over-speed, such as a loss of containment event. Meeting the goal of risk minimization is complicated by the large range of turbine types present in a typical fleet. These turbines may have different pitch systems, over-speed detection systems, and also different levels of functional redundancy, implying different levels of risk. The purpose of this work is to carry out a quantitative comparison of over-speed risk in different turbine configurations, using a Markov process to model detection of faults and repair actions. In the medium-long term, the risk associated with different assets can be used as a decision-making aid. For example, if the operator is a utility, it may want to avoid purchasing high-risk sites in the future, or may need to develop mitigation strategies for turbines at high risk of over-speed.

Now, voyager? The increasing marine use of fuel cells

From yachts to ferries, car carriers to submarines, a diverse fleet of ecoboats utilize fuel cell technology, with more applications on the near horizon. In this article we look at the wide variety of fuel cell projects both above and below the waves, and at some of the concept and demonstration vessels being planned.

An update on DOE's Phase II and Phase III mercury control technology R&D program

The U.S. Department of Energy's National Energy Technology Laboratory, under the Office of Fossil Energy's Innovations for Existing Plants Program, carried out a comprehensive Hg research and development program for coal-fired power generation facilities since the mid-1990s. Working collaboratively with the U.S. Environmental Protection Agency, the Electric Power Research Institute, power plant operators, state and local agencies, and a host of research organizations and academic institutions, the Program identified the major factors that affect mercury speciation and capture in coal combustion flue gas and funneled this knowledge into the development of a suite of mercury control technologies for the diverse fleet of U.S. coal-fired power plants. The high performance observed during full-scale field testing has given coal-fired power plant operators the confidence to begin deploying technology. As of March 2009, more than 130 full-scale activated carbon injection systems have been ordered by the U.S. coal-fired power generators. These contracts include both new and retrofit installations and represent over 55 GW of coal-based electric generating capacity.

The IVQ regime in Norway: A stable alternative to an ITQ regime?

Abstract Since the introduction of quotas and licences as important management tools, Norway has insisted on an individual vessel quota regime (IVQ). The main argument has been to avoid market-based transactions of quotas and vessels and secure stability in regard to a diverse fleet structure and decentralized ownership of scarce cod resources. Thus, an individual transferable quota system (ITQ) with a high degree of transactions and the potential for a heavy concentration of quota ownership and fewer vessels has never been an alternative. However, since the late 80s, the trawler fleet has been trapped within a web of unprofitable overcapacity. Within the frame of a closed management regime and a path-dependent IVQ system, the quota regime has been forced towards a market-orientated system for transactions. In this article, we analyze the Norwegian IVQ system and discuss whether the aggregate effects of the IVQ regime are congruent with the models’ profound ideals.

Exhaust Temperature Profiles for Application of Passive Diesel Particulate Filters to Solid Waste Collection Vehicles in California

To reduce public exposure to diesel particulate matter (DPM), the California Air Resources Board has begun adoption of a series of rules to reduce these emissions from in-use heavy-duty vehicles. Passive diesel particulate filter (DPF) after-treatment technologies are a cost-effective method to reduce DPM emissions and have been used on a variety of vehicles worldwide. Two passive DPFs were interim-verified in California and approved federally for use in most 1994–2002 engine families for vehicles meeting min engine exhaust temperature requirements for successful filter regeneration. Some vehicles, however, may not be suited to passive DPFs because of lower engine exhaust temperatures. The purpose of this study was to determine the applicability of two types of passive DPFs to solid waste collection vehicles, the group of vehicles for which California recently mandated in-use DPM reductions. We selected 60 collection vehicles to represent the four main types of collection vehicle duty cycles—roll-offs, and front-end, rear, and side loaders—and collected second-by-second engine exhaust temperature readings for one week from each vehicle. As a group, the collection vehicles exhibited low engine exhaust temperatures, making the application of passive DPFs to these vehicles difficult. Only 35% of tested vehicles met the temperature requirements for one passive DPF, whereas 60% met the temperature requirements for the other. Engine exhaust temperatures varied by vehicle type. Side and front-end loaders met the engine exhaust temperature requirements in the greatest number of cases with ∼50–90% achieving the required regeneration temperatures. Only 8–25% of the rear loader and roll-off collection vehicles met the engine exhaust temperature requirements. Solid waste collection vehicles represent a diverse fleet with a variety of duty cycles. Low engine exhaust temperatures will need to be addressed for successful use of passive DPFs in this application.

Solving the aerial fleet refueling problem using group theoretic tabu search

The aerial fleet refueling problem (AFRP) is concerned with the efficient and effective use of a heterogeneous set of tanker (refueling) aircraft, located at diverse geographical locations, in the required operations associated with the deployment of a diverse fleet of military aircraft to a foreign theater of activity. Typically, the “receiving” aircraft must traverse great distances over large bodies of water and/or over other inhospitable environs where no ground based refueling resources exist. Lacking the ability to complete their flights without refueling, each receiving aircraft must be serviced one or more times during their deployment flights by means of in-flight refueling provided by one of the available tanker aircraft. The receiving aircraft, aggregated into receiver groups (RGs) that fly together, have stipulated departure and destination bases and each RG's arrival time is bounded by a stated desired earliest and latest time. The excellence of a suggested solution to this very challenging decision making problem is measured relative to a rigorously defined hierarchical multicriteria objective function. This paper describes how the AFRP for the Air Mobility Command (AMC), Scott Air Force Base, IL, is efficiently solved using group theoretic tabu search (GTTS). GTTS uses the symmetric group on n letters ( S n ) and applies it to this problem using the Java™ language.

U S WEST Implements a Cogent Analytical Model for Optimal Vehicle Replacement

We developed and implemented a model-based replacement process for a diverse fleet of vehicles at U S WEST, a major telecommunications company (since June 2000, Qwest Communications International). The model considers relevant age-dependent factors, including annual maintenance cost, opportunity cost of downtime, depreciation, and salvage value. It assigns a replacement score to each candidate vehicle based on age, type, estimated replacement cost, and estimated maintenance cost in the next year of operation. The model then rank-orders the vehicles by score and identifies them for replacement subject to a budget constraint on fleet capital expenditure. Through implementation of the model-based process, the company expects an annual benefit of more than $13 million.

U S WEST Implements a Cogent Analytical Model for Optimal Vehicle Replacement

AboutSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked InEmail Go to Section HomeInterfacesVol. 31, No. 5 U S WEST Implements a Cogent Analytical Model for Optimal Vehicle ReplacementDennis C. Dietz, Paul A. KatzDennis C. Dietz, Paul A. KatzPublished Online:1 Oct 2001https://doi.org/10.1287/inte.31.5.65.9659AbstractWe developed and implemented a model-based replacement process for a diverse fleet of vehicles at U S WEST, a major telecommunications company (since June 2000, Qwest Communications International). The model considers relevant age-dependent factors, including annual maintenance cost, opportunity cost of downtime, depreciation, and salvage value. It assigns a replacement score to each candidate vehicle based on age, type, estimated replacement cost, and estimated maintenance cost in the next year of operation. The model then rank-orders the vehicles by score and identifies them for replacement subject to a budget constraint on fleet capital expenditure. Through implementation of the model-based process, the company expects an annual benefit of more than $13 million. Previous Back to Top Next FiguresReferencesRelatedInformationCited byEquipment Replacement Analysis: A Literature Review and Directions for Future Research27 May 2014 | The Engineering Economist, Vol. 59, No. 2Vehicle Replacement in the International Committee of the Red Cross18 January 2012 | Production and Operations Management, Vol. 22, No. 2Vehicle Replacement in the International Committee of the Red CrossSSRN Electronic Journal, Vol. 175 Volume 31, Issue 5September-October 2001Pages 1-143 Article Information Metrics Information Published Online:October 01, 2001 © 2001 INFORMSCite asDennis C. Dietz, Paul A. Katz, (2001) U S WEST Implements a Cogent Analytical Model for Optimal Vehicle Replacement. Interfaces 31(5):65-73. https://doi.org/10.1287/inte.31.5.65.9659 KeywordsINVENTORY-PRODUCTION, POLICIESMAINTENANCE-REPLACEMENTINDUSTRIES—COMPUTER-ELECTRONICPDF download

Status of shark resources in the southern Gulf of Mexico and Caribbean: implications for management

This paper reviews current knowledge on shark biology, ecology, and fisheries in Mexican waters of the Gulf of Mexico, focusing on management implications. Original and literature data are summarized covering distribution, migrations, nursery areas, structure of the landings and catch trends. There are at least 34 species of shark in the area, most of them from the genera Carcharhinus and Sphyrna. Fourteen of these species are important in the fisheries. The biology and ecology of shark stocks in the southern Gulf of Mexico are poorly known. Tagging studies have shown movements of shark from the eastern US coast to the southern Gulf of Mexico, but migrations have not been properly characterized due to limited tagging in Gulf waters. There are important shark nurseries for at least five species in the protected waters of Chetumal Bay (Q. Roo), Yalahau Lagoon (Q. Roo), and Terminos Lagoon (Camp.). Sharks contribute approximately 3.5% of the total fishery catches in this region, averaging about 13000 t during 1983–1992. Sharks are harvested by a diverse fleet of small-scale and large-scale vessels utilizing longlines or gillnets. There seems to be an excessive fishing of juveniles from many of the most important species. Areas of priority for future research that are pre-requisite for international management are: the life cycle of the main species in the southern Gulf of Mexico; in-depth study of coastal nursery areas; large scale tagging programmes coupled with population genetics studies; gathering of fisheries data and fisheries-independent abundance information; and socio-economic studies of the fisheries. Some precautionary management measures are proposed.