An Analysis of the Technical and Economic Potential for Mid-Scale Distributed Wind

This report examines the status, restrainers, drivers, and estimated development potential of mid-scale (10 kW to 5000 kW) distributed wind projects. This segment of the wind market has not enjoyed the same growth that central-station wind has experienced. The purpose of this report is to analyze why, and to assess the market potential for this technology under current market and policy conditions. As discussed in section 2, one of the most significant barriers to the development of distributed wind is a general scarcity of turbine choices and turbine inventory available for purchase. Most turbine manufacturers have scaled back their involvement in the mid-scale market segments in favor of larger turbines suitable for large, central-station wind farms. Those distributed-scale turbines that are available are often relatively expensive (on a $/kW basis), hard to order in single units or small lots, and suffer from long delivery delays. Section 3 discusses various other factors—both positive and negative—that affect the viability of distributed wind. In addition to the product scarcity described in section 2, distributed wind is challenged by relatively poor productivity (compared with more modern large turbines), siting issues, burdensome interconnection rules, aesthetic concerns, and fragmented state rules regarding net metering. Several other factors favor distributed wind: areas of high and rising retail electricity prices, increasingly favorable public policies, and greater community interest in the environmental and economic benefits of renewable energy. As examined in section 4, the study evaluated the economic potential for distributed wind in the contiguous United States, excluding Alaska and Hawaii. The analysis began with a GIS screening process to eliminate areas that are technically impractical for distributed wind. Sites were eliminated in areas where: • Elevation was too high; • Slope was too steep; • Population density was too great; • Wind Power Class was less than 2; and • Areas legally excluded from wind-power development, such as national parks. After screening out ineligible sites, more than 3.6 million surviving sites were evaluated to determine whether distributed wind would be financially feasible. Certain customer types were excluded from the study, such as agricultural, construction companies, and military facilities, because they lacked data necessary for the analysis. The financial model considered: • Wind resources; • Wholesale and retail power prices; • Renewable Energy Credit (REC) prices; • Customer type (community wind, commercial, industrial, or public facility); • Project size; • Turbine technical and financial characteristics; • Onsite and offsite energy use; and • Incentives. The results varied significantly by customer class. Overall, the study showed that 67,100 out of the 3,611,655 sites/areas that were analyzed for economic viability yielded a positive net present value under current market conditions and policies and including all applicable state and federal incentives. To assess the potential of new technology, two virtual wind turbines—the NREL 250 and NREL 500—were included in the analysis. These virtual turbines were compared to existing 250 kW and 500 kW turbines. Overall, the study showed that 204,677 sites analyzed had positive net present values with the virtual turbines compared with 10,407 economically successful projects with existing 250 kW and 500 kW turbines. These numbers do not include the application of capped state and federal incentives. The following crucial changes could expand distributed wind development into the future. • Improvements in technology; • Reductions in cost; • Greater productivity at lower wind speeds; and • Greater policy support

An Analysis of the Technical and Economic Potential for Mid-Scale Distributed Wind

This report examines the status, restrainers, drivers, and estimated development potential of mid-scale (10 kW to 5000 kW) distributed wind projects. This segment of the wind market has not enjoyed the same growth that central-station wind has experienced. The purpose of this report is to analyze why, and to assess the market potential for this technology under current market and policy conditions. As discussed in section 2, one of the most significant barriers to the development of distributed wind is a general scarcity of turbine choices and turbine inventory available for purchase. Most turbine manufacturers have scaled back their involvement in the mid-scale market segments in favor of larger turbines suitable for large, central-station wind farms. Those distributed-scale turbines that are available are often relatively expensive (on a $/kW basis), hard to order in single units or small lots, and suffer from long delivery delays. Section 3 discusses various other factors—both positive and negative—that affect the viability of distributed wind. In addition to the product scarcity described in section 2, distributed wind is challenged by relatively poor productivity (compared with more modern large turbines), siting issues, burdensome interconnection rules, aesthetic concerns, and fragmented state rules regarding net metering. Several other factors favor distributed wind: areas of high and rising retail electricity prices, increasingly favorable public policies, and greater community interest in the environmental and economic benefits of renewable energy. As examined in section 4, the study evaluated the economic potential for distributed wind in the contiguous United States, excluding Alaska and Hawaii. The analysis began with a GIS screening process to eliminate areas that are technically impractical for distributed wind. Sites were eliminated in areas where: • Elevation was too high; • Slope was too steep; • Population density was too great; • Wind Power Class was less than 2; and • Areas legally excluded from wind-power development, such as national parks. After screening out ineligible sites, more than 3.6 million surviving sites were evaluated to determine whether distributed wind would be financially feasible. Certain customer types were excluded from the study, such as agricultural, construction companies, and military facilities, because they lacked data necessary for the analysis. The financial model considered: • Wind resources; • Wholesale and retail power prices; • Renewable Energy Credit (REC) prices; • Customer type (community wind, commercial, industrial, or public facility); • Project size; • Turbine technical and financial characteristics; • Onsite and offsite energy use; and • Incentives. The results varied significantly by customer class. Overall, the study showed that 67,100 out of the 3,611,655 sites/areas that were analyzed for economic viability yielded a positive net present value under current market conditions and policies and including all applicable state and federal incentives. To assess the potential of new technology, two virtual wind turbines—the NREL 250 and NREL 500—were included in the analysis. These virtual turbines were compared to existing 250 kW and 500 kW turbines. Overall, the study showed that 204,677 sites analyzed had positive net present values with the virtual turbines compared with 10,407 economically successful projects with existing 250 kW and 500 kW turbines. These numbers do not include the application of capped state and federal incentives. The following crucial changes could expand distributed wind development into the future. • Improvements in technology; • Reductions in cost; • Greater productivity at lower wind speeds; and • Greater policy support

Direct magnetic resonance arthrography of the knee: utility of axial traction

The purpose of this study was to determine the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography examination of the knee in terms of joint space width and amount of contrast material between the cartilage surfaces. Direct knee MR arthrography was performed in 11 patients on a 3-T MR imaging unit using a T1-weighted isotropic gradient echo sequence in a coronal plane with and without axial traction of 15kg. Joint space widths were measured at the level of the medial and the lateral femorotibial joint with and without traction. The amount of contrast material in the medial and lateral femorotibial joint was assessed independently by two musculoskeletal radiologists in a semiquantitative manner using three grades (‘absence of surface visualization, ‘partial surface visualization or ‘complete surface visualization'). With traction, joint space width increased significantly at the lateral femorotibial compartment (mean = 0.55mm, p = 0.0105) and at the medial femorotibial compartment (mean = 0.4mm, p = 0.0124). There was a trend towards an increased amount of contrast material in the femorotibial compartment with axial traction. Direct MR arthrography of the knee with axial traction showed a slight and significant increase of the width of the femorotibial compartment with a trend towards more contrast material between the articular cartilage surface

On the coexistence of cooperators, defectors and conditional cooperators in the multiplayer iterated Prisoner's Dilemma

Recent experimental evidence [Gruji\'c et al., PLoS ONE 5, e13749 (2010)] on the spatial Prisoner's Dilemma suggests that players choosing to cooperate or not on the basis of their previous action and the actions of their neighbors coexist with steady defectors and cooperators. We here study the coexistence of these three strategies in the multiplayer iterated Prisoner's Dilemma by means of the replicator dynamics. We consider groups with n = 2, 3, 4 and 5 players and compute the payoffs to every type of player as the limit of a Markov chain where the transition probabilities between actions are found from the corresponding strategies. We show that for group sizes up to n = 4 there exists an interior point in which the three strategies coexist, the corresponding basin of attraction decreasing with increasing number of players, whereas we have not been able to locate such a point for n = 5. We analytically show that in the infinite n limit no interior points can arise. We conclude by discussing the implications of this theoretical approach on the behavior observed in experiments.Comment: 12 pages, 10 figures, uses elsart.cl

Are Subjects Making Financial Decisions in Lab Auctions or Are They Just Gambling?

Optimal bidding strategies in first-price and Dutch auctions are theoretically isomorphic but depend on bidder risk attitudes. However, laboratory experiments consistently find different behaviour between auction formats. This article explores whether the notion in psychology that financial and gambling risks are viewed differently can explain the discrepancy. Ultimately, the evidence does not support this hypothesis, but a bidder\u27s propensity to gamble is associated with how much risk he takes in both auctions whereas his propensity to take financial risks is not. The results suggest that subjects may view themselves as gambling in laboratory auctions rather than making financial decisions

Analysis of the Technical and Economic Potential for Mid-Scale Distributed Wind: December 2007 - October 31, 2008

This report examines the status, restrainers, drivers, and estimated development potential of mid-scale (10 kW - 5000 kW) distributed wind energy projects

Effects of inhomogeneous activity of players and noise on cooperation in spatial public goods games

We study the public goods game in the noisy case by considering the players with inhomogeneous activity teaching on a square lattice. It is shown that the introduction of the inhomogeneous activity of teaching of the players can remarkably promote cooperation. By investigating the effects of noise on cooperative behavior in detail, we find that the variation of cooperator density $\rho_C$ with the noise parameter $\kappa$ displays several different behaviors: $\rho_C$ monotonically increases (decreases) with $\kappa$; $\rho_C$ firstly increases (decreases) with $\kappa$ and then it decreases (increases) monotonically after reaching its maximum (minimum) value, which depends on the amount of the multiplication factor $r$, on whether the system is homogeneous or inhomogeneous, and on whether the adopted updating is synchronous or asynchronous. These results imply that the noise plays an important and nontrivial role in the evolution of cooperation.Comment: 4 pages, 4 figure

Promote cooperation by localised small-world communication

The emergence and maintenance of cooperation within sizable groups of unrelated humans offer many challenges for our understanding. We propose that the humans' capacity of communication, such as how many and how far away the fellows can build up mutual communications, may affect the evolution of cooperation. We study this issue by means of the public goods game (PGG) with a two-layered network of contacts. Players obtain payoffs from five-person public goods interactions on a square lattice (the interaction layer). Also, they update strategies after communicating with neighbours in learning layer, where two players build up mutual communication with a power law probability depending on their spatial distance. Our simulation results indicate that the evolution of cooperation is indeed sensitive to how players choose others to communicate with, including the amount as well as the locations. The tendency of localised communication is proved to be a new mechanism to promote cooperation.Comment: 6 pages, 4 figure

The Effects of Shilling on Final Bid Prices in Online Auctions

An increasing number of reports of online auction fraud are of growing concern to auction operators and participants. In this research, we discuss reserve price shilling, where a bidder shills in order to avoid paying auction house fees, rather than to drive up the price of the final bid. We examine the effect that premium bids, since they are linked with reserve price shill bids, have upon the final selling price. We use 10,260 eBay auctions during April 2001, and identify 1,389 auctions involving 493 sellers and 1,314 involved in concurrent auctions that involving the exact same item. We find that premium bidding occurs 23 % of the time, in 263 of the 1,389 auctions. Using a theoretical perspective involving valuation signals, we show that other bidders may view high bids as signals that an item is worth more. Thus, they may be willing to pay more for the item than items that do not receive premium bids. The implications are disturbing in that sellers may be more motivated to enter a shill bid in order to drive up the final price in an online auction. We also examine and report on alternative hypotheses involving winner’s curse and the possibility of reserve price shill bids. Our results are developed in the context of a weighted leas

An experimental investigation of asymmetric contests

publication-status: Acceptedtypes: ArticleNOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Industrial Organization. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Industrial Organization, Elsevier, vol. 27(5), 2009, DOI: 10.1016/j.ijindorg.2009.01.004NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Industrial Organization. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Industrial Organization, Elsevier, vol. 27(5), 2009, DOI: 10.1016/j.ijindorg.2009.01.00