Carbon taxation and feed-in tariffs: evaluating the effect of network and market properties on policy effectiveness

This paper evaluates how the effect of introducing a carbon emission tax and/or feed-in tariffs on capacity expansion decisions of generating companies varies depending on the number and size of competing firms and technical conditions of the network. To do so, it uses a Nash–Cournot model of the electricity market. This model is then applied to the IEEE 6-bus network. We study three cases: one with only a carbon tax consistent with current carbon prices; one with only a feed-in tariff consistent with current US levels, and one with simultaneous carbon taxation and feed-in tariff. We show that, at least in our case, the quantity of renewable capacity expansion and the electricity prices depend more significantly on the technical conditions of the network and the number of competitors in the market than it depends on the presence of economic penalties or incentives. We also show how interactions between imperfectly competitive markets and physical networks can produce counterintuitive results, such as an increase in consumer prices as a result of a reduction in network congestion. Our results imply that no two countries would experience the same effects from a policy on carbon tax and feed-in tariff if their electricity market does not have similarities in technical and competitive conditions

Tabu search - a guided tour

The main purpose of this paper is to provide an overview of the ideas behind Tabu Search - one of the most popular metaheuristic appoaches. For the sake of concreteness a simple example of the traveling salesman problem will be used in the discussion to illustrate the process of designing a Tabu Search algorithm. In addition, some extensions will be presented. Finally, applications will also be provided as well as references to more specialized publications

Tabu Search for target-radar assignment

In this paper the problem of assigning air-defense illumination radars to enemy targets is presented. A Tabu Search metaheuristic solution is described and the results achieved are compared to those of other heuristic approaches. Implementation and experimental aspects are discussed. It is argued that Tabu Search could be used in near realtime decision making systems

Perfect Storm or Perfect Opportunity? Future Scenarios for the Electricity Sector

© 2014 Elsevier Inc. All rights reserved.. This chapter applies futures thinking to explore possible scenarios that electric utilities may face in the coming decades. The chapter applies a top-down approach to identify the key drivers that could influence business models. It describes three possible futures in detail. Firstly, the "centralized" future moves toward decarbonization but retains the centralized model present in most power systems today. In contrast, the "decentralized" future moves toward greater decentralization while retaining a significant role for the grid. The "disconnected" future moves to complete decentralization, with most customers disconnecting from the grid entirely. The chapter concludes that all three scenarios are possible and will have important implications for electric utilities. Wise businesses will adopt a risk management approach

The ostomy leak impact tool: development and validation of a new patient-reported tool to measure the burden of leakage in ostomy device users

Abstract Background Leakage is a major concern for people who use a stoma, but people’s experience and its impact is not well understood. This study aimed to establish a definition of leakage through clinical and user input. This information was used to develop and validate a new measurement tool to understand the impact of leakage for people using a stoma appliance, in the UK, US, France, and Denmark. Methods Participants were recruited from a panel of users, hosted by Coloplast, that includes people who currently use Coloplast products. Six clinicians and 41 users took part in concept elicitation interviews. The qualitative findings were used to draft items. A panel of clinical experts was organized to develop and validate items (N = 6). Cognitive debrief interviews were conducted with five users in each country, which resulted in removing some items and revising the measure. A psychometric validation was conducted with 340 people in four countries whereby participants were asked to complete a series of measures online. Full psychometric analyses including validity and reliability were conducted. Results A final tool was established consisting of three domains related to the burden of leakage: “Emotional impact,” “Usual and social activities,” and “Coping and control.” Convergent validity was evaluated by benchmarking to existing health-related quality of life instruments (domains of SF-36 and Ostomy-Q). This showed high correlation between domains of the leakage tool and other measures, in particular for the Emotional impact domain when compared with SF-36 Emotional well-being and Ostomy-Q Confidence domain (p  0.92). Conclusion The study highlights how users define leakage and its impact in a way that is meaningful to them. This information has been used to develop an instrument to measure leakage which can potentially be used by clinicians and researchers. The instrument demonstrated evidence supporting its reliability and validity as an outcome measure to assess the impact of leakage in stoma care

Effect of the once-daily human GLP-1 analogue liraglutide on appetite, energy intake, energy expenditure and gastric emptying in type 2 diabetes

AimsLiraglutide reduces bodyweight in patients with type 2 diabetes mellitus (T2DM). This study aimed to investigate the mechanisms underlying this effect.MethodsThe comparative effects of liraglutide, glimepiride and placebo on energy intake, appetite, nausea, gastric emptying, antral distension, bodyweight, gastrointestinal hormones, fasting plasma glucose and resting energy expenditure (REE), were assessed in subjects with T2DM randomised to treatment A (liraglutide-placebo), B (placebo-glimepiride) or C (glimepiride-liraglutide). Assessments were performed at the end of each 4-week treatment period.ResultsEnergy intake was less (NS) with liraglutide vs placebo and glimepiride, and 24-h REE was higher (NS) with liraglutide vs placebo and glimepiride. Fasting hunger was less (p=0.01) with liraglutide vs placebo and glimepiride, and meal duration was shorter with liraglutide (p=0.002) vs placebo. Paracetamol AUC(0-60 min) and C(max) were less (pConclusionLiraglutide caused decreased gastric emptying and increased reduction in bodyweight. The mechanisms of the liraglutide-induced weight-loss may involve a combined effect on energy intake and energy expenditure.Michael Horowitz, Anne Flint, Karen L. Jones, Charlotte Hindsberger, Mads F. Rasmussen, Christoph Kapitza, Selena Doran, Thomas Jax, Milan Zdravkovic, Ian M. Chapma