958 resultados para price of electricity
Resumo:
This thesis reviews the main methodological developments in public sector investment appraisal and finds growing evidence that appraisal techniques are not fulfilling their earlier promise. It is suggested that an important reason for this failure lies in the inability of these techniques to handle uncertainty except in a highly circumscribed fashion. It is argued that a more fruitful approach is to strive for flexibility. Investment projects should be formulated with a view to making them responsive to a wide range of possible future events, rather than embodying a solution which is optimal for one configuration of circumstances only. The distinction drawn in economics between the short and the long run is used to examine the nature of flexibility. The concept of long run flexibility is applied to the pre-investment range of choice open to the decisionmaker. It is demonstrated that flexibility is reduced at a very early stage of decisionmaking by the conventional system of appraisal which evaluates only a small number of options. The pre-appraisal filtering process is considered further in relation to decisionmaking models. It is argued that for public sector projects the narrowing down of options is best understood in relation to an amended mixed scanning model which places importance on the process by which the 'national interest ' is determined. Short run flexibility deals with operational characteristics, the degree to which particular projects may respond to changing demands when the basic investment is already in place. The tension between flexibility and cost is noted. A short case study on the choice of electricity generating plant is presented. The thesis concludes with a brief examination of the approaches used by successive British governments to public sector investment, particularly in relation to the nationalised industries
Resumo:
Infection is a major clinical problem associated with the use of intravenous catheters.The efficacy of a direct electric current (10µA, 9V) via electrode-conducting carbon impregnated catheters to prevent colonisation of catheters by micro-organisms was investigated. The range of organisms susceptible to 10µA was determined by a zone of inhibition test. The catheters acting as the anode and the cathode were inserted into a nutrient agar plate inoculated with a lawn of bacteria. There was no zone of inhibition observed around the anode. Organisms susceptible to 10µA at the cathode were Staphylococcus aureus (2 strains), Staphylococcus epidermidis (5 strains), Escherichia coli and Klebsiella pneumoniae (2 strains each), and one strain of the following micro-organisms: Staphylococcus hominis, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. The zones ranged from 6 to 16 mm in diameter according to the organisms under test. The zone size was proportional to the amperage (10 - 100 µA) and the number of organisms on the plate. Ten µA did not prevent adhesion of staphylococci to the cathode nor did it affect their growth in nutrient broth. However, it was bactericidal to adherent bacteria on the cathodal catheter and significantly reduced the number of bacteria on the catheter after 4 to 24 h application of electricity. The antimicrobial activity of low amperage electric current under anaerobic conditions and in the absence of chloride ions against bacteria attached to the surface of a current carrying electrode was also investigated.The mechanisms of the bactericidal activity associated with the cathode were investigated with S. epidermidis and S. aureus. The inhibition zone was greatly reduced in the presence of catalase. There was no zone around the cathode when the test was carried out under anaerobic conditions. Hydrogen peroxide was produced at the cathode surface under aerobic conditions, but not in the absence of oxygen. A salt-bridge apparatus was used to demonstrate further that hydrogen peroxide was produced at the cathode, and chlorine at the anode. The antimicrobial activity of low amperage electric current under anaerobic conditions and in the absence of chloride ions against bacteria attached to the surface of a current carrying electrode was also investigated. Antibacterial activity was reduced under anaerobic conditions, which is compatible with the role of hydrogen peroxide as a primary bactericidal agent of electricity associated with the cathode. A reduction in chloride ions did not significantly reduce the antibacterial activity suggesting chlorine plays only a minor role in the bactericidal activity against organisms attached to anodal electrode surfaces. The bactericidal activity of electric current associated with the cathode and H202 was greatly reduced in the presence of 50 μM to 0.5 mM magnesium ions in the test menstrum. Ten μA applied via the catheters did not prevent the initial biofilm growth by the adherent bacteria but reduced the number of bacteria in the biofilm by 2 log order aiter 24 h. The results suggested that 10 μA may prevent the colonisation of catheters by both the extra~ and intra-luminal routes. The localised production of hydrogen peroxide and chlorine and the intrinsic activity due to electric current may offer a useful method for the eradication of bacteria from catheter surfaces.
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The work presented in this thesis concerns itself with the application of Demand Side Management (DSM) by industrial subsector as applied to the UK electricity industry. A review of the origins of DSM in the US and the relevance of experience gained to the UK electricity industry is made. Reviews are also made of the current status of the UK electricity industry, the regulatory system, and the potential role of DSM within the prevalent industry environment. A financial appraisal of DSM in respect of the distribution business of a Regional Electricity Company (REC) is also made. This financial appraisal highlights the economic viability of DSM within the context of the current UK electricity industry. The background of the work presented above is then followed by the construction of a framework detailing the necessary requirements for expanding the commercial role of DSM to encompass benefits for the supply business of a REC. The derived framework is then applied, in part, to the UK ceramics manufacturing industry, and in full to the UK sanitaryware manufacturing industry. The application of the framework to the UK sanitaryware manufacturing industry has required the undertaking of a unique first-order energy audit of every such manufacturing site in the UK. As such the audit has revealed previously unknown data on the timings and magnitude of electricity demand and consumption attributable to end-use manufacturing technologies and processes. The audit also served to reveal the disparity in the attitudes toward energy services, and thus by implication towards DSM, of manufacturers within the same Standard Industrial Classification (SIC) code. In response to this, attempt is made to identify the underlying drivers which could cause this variation in attitude. A novel approach to the market segmentation of the companies within the UK ceramics manufacturing sector has been utilised to classify these companies in terms of their likelihood to participate in DSM programmes through the derived Energy Services approach. The market segmentation technique, although requiring further development to progress from a research based concept, highlights the necessity to look beyond the purely energy based needs of manufacturing industries when considering the utilisation of the Energy Services approach to facilitate DSM programs.
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Power generation from biomass is a sustainable energy technology which can contribute to substantial reductions in greenhouse gas emissions, but with greater potential for environmental, economic and social impacts than most other renewable energy technologies. It is important therefore in assessing bioenergy systems to take account of not only technical, but also environmental, economic and social parameters on a common basis. This work addresses the challenge of analysing, quantifying and comparing these factors for bioenergy power generation systems. A life-cycle approach is used to analyse the technical, environmental, economic and social impacts of entire bioelectricity systems, with a number of life-cycle indicators as outputs to facilitate cross-comparison. The results show that similar greenhouse gas savings are achieved with the wide variety of technologies and scales studied, but land-use efficiency of greenhouse gas savings and specific airborne emissions varied substantially. Also, while specific investment costs and electricity costs vary substantially from one system to another the number of jobs created per unit of electricity delivered remains roughly constant. Recorded views of stakeholders illustrate that diverging priorities exist for different stakeholder groups and this will influence appropriate choice of bioenergy systems for different applications.
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Greenhouse cultivation is an energy intensive process therefore it is worthwhile to introduce energy saving measures and alternative energy sources. Here we show that there is scope for energy saving in fan ventilated greenhouses. Measurements of electricity usage as a function of fan speed have been performed for two models of 1.25 m diameter greenhouse fans and compared to theoretical values. Reducing the speed can cut the energy usage per volume of air moved by more than 70%. To minimize the capital cost of low-speed operation, a cooled greenhouse has been built in which the fan speed responds to sunlight such that full speed is reached only around noon. The energy saving is about 40% compared to constant speed operation. Direct operation of fans from solar-photovoltaic modules is also viable as shown from experiments with a fan driven by a brushless DC motor. On comparing the Net Present Value costs of the different systems over a 10 year amortization period (with and without a carbon tax to represent environmental costs) we find that sunlight-controlled system saves money under all assumptions about taxation and discount rates. The solar-powered system, however, is only profitable for very low discount rates, due to the high initial capital costs. Nonetheless this system could be of interest for its reliability in developing countries where mains electricity is intermittent. We recommend that greenhouse fan manufacturers improve the availability of energy-saving designs such as those described here.
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The use of the pyrolysis process to obtain valuable products from biomass is amongst the technologies being investigated as a source for renewable energy. The pyrolysis process yields products such as biochar, bio-oil and non condensable gases. The main objective of this project is to increase energy recovery from sewage sludge by utilising the intermediate pyrolysis process. The intermediate pyrolysis has a residence time ranging from 5 to 10 minutes. The main product yields from sewage sludge pyrolysis are 50 wt% biochar, 40 wt% bio-oil and 10 wt% non condensable gases. The project was carried out on a pilot plant scale reactor with a load capacity of 20 kg/h. This enabled a high yield of biochar and bio-oil. The characterisation of the products indicated that the organic phase of the bio-oil had good fuel properties such as having high energy content of 39 MJ/kg, low acid number of 21.5, high flash point of 150 and viscosity of 35 cSt. An increase in pyrolysis experiments enabled large quantities of pyrolysis oil production. Co-pyrolysis of sewage sludge was carried out on laboratory scale with mixed wood, rapeseed and straw. It found that there was an increase in bio-oil quantity with rapeseed while co-pyrolysis with wood helped to mask the smell of the sludge pyrolysis oil. Engine test were successfully carried out in an old Lister engine with pyrolysis oil fractions of 30% and 50% blended with biodiesel. This indicates that these pyrolysis oil fractions can be used in similar engine types without any problems however long term effects in ordinary engines are unknown. An economic evaluation was carried out about the implementation of the intermediate pyrolysis process for electricity production in a CHP using the pyrolysis oil. The prices of electricity per kWh were found to be very high.
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This thesis presents a techno-economic investigation of the generation of electricity from marine macroalgae (seaweed) in the UK (Part 1), and the production of anhydrous ammonia from synthesis gas (syngas) generated from biomass gasification (Part 2). In Part 1, the study covers the costs from macroalgae production to the generation of electricity via a CHP system. Seven scenarios, which varied the scale and production technique, were investigated to determine the most suitable scale of operation for the UK. Anaerobic digestion was established as the most suitable technology for macroalgae conversion to CHP, based on a number of criteria. All performance and cost data have been taken from published literature. None of the scenarios assessed would be economically viable under present conditions, although the use of large-scale electricity generation has more potential than small-scale localised production. Part 2 covers the costs from the delivery of the wood chip feedstock to the production of ammonia. Four cases, which varied the gasification process used and the scale of production, were investigated to determine the most suitable scale of operation for the UK. Two gasification processes were considered, these were O2-enriched air entrained flow gasification and Fast Internal Circulating Fluidised Bed. All performance and cost data have been taken from published literature, unless otherwise stated. Large-scale (1,200 tpd) ammonia production using O2-enriched air entrained flow gasification was determined as the most suitable system, producing the lowest ammonia-selling price, which was competitive to fossil fuels. Large-scale (1,200 tpd) combined natural gas/biomass syngas ammonia production also generated ammonia at a price competitive to fossil fuels.
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Areas covered: The review discusses the main challenges of ODT manufacturing process and the emerging solutions featured at early drug development stages. The research specifically describes the methods reported for taste masking/assessment and solubilisation of unpalatable and poorly soluble drugs, respectively. Furthermore, this review highlights the techniques used for developing modified-release ODTs, an emerging area in the field. In addition, it also discusses the poor flowability and segregation problems of directly compressed powders. Moreover, the review describes the tests reported in the literature for ODT disintegration time assessment since a universal technique is still non-existent. Expert opinion: The approaches used to overcome the manufacturing challenges often have a bearing on the price of the end product. However, despite the technical and regulatory challenges, ODTs can offer many advantages over the conventional dosage forms if accompanied by suitable adjuvant technologies and in vitro analytical tools. © 2014 Informa UK, Ltd. Introduction: Orally disintegrating tablets (ODTs) provide several advantages over conventional tablets such as suitability for patients with swallowing difficulties and faster onset of action. The manufacture of ODTs by compression/tableting offers a practical and cost-effective strategy over the freeze drying (lyophilisation) method. Nonetheless, the FDA recommends a disintegration time of 30 s and a maximum weight of 500 mg for a tablet to be labelled as an ODT. These requirements, alongside other desirable product properties, have created a number of challenges for the formulator to overcome while developing compressed ODTs.
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This review offers new perspectives on the subject and highlights an area in need of further research. It includes an analysis of current scientific literature mainly covering the last decade and examines the trends in the development of electronic, acoustic and optical-fiber humidity sensors over this period. The major findings indicate that a new generation of sensor technology based on optical fibers is emerging. The current trends suggest that electronic humidity sensors could soon be replaced by sensors that are based on photonic structures. Recent scientific advances are expected to allow dedicated systems to avoid the relatively high price of interrogation modules that is currently a major disadvantage of fiber-based sensors.
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The evaluation from experimental data, of physical quantities, which enter into the electromagnetic Maxwell equations, is described as inverse optical problem. The functional relations between the dependent and independent variables are of transcendental character and numeric procedures for evaluation of the unknowns are largely used. Herein, we discuss a direct approach to the solution, illustrated by a specific example of determination of thin films optical constants from spectrophotometric data. New algorithm is proposed for the parameters evaluation, which does not need an initial guess of the unknowns and does not use iterative procedures. Thus we overcome the intrinsic deficiency of minimization techniques, such as gradient search methods, Simplex methods, etc. The price of it is a need of more computing power, but our algorithm is easily implemented in structures such as grid clusters. We show the advantages of this approach and its potential for generalization to other inverse optical problems.
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Performance analysis has become a vital part of the management practices in the banking industry. There are numerous applications using DEA models to estimate efficiency in banking, and most of them assume that inputs and outputs are known with absolute precision. Here, we propose new Fuzzy-DEA α-level models to assess underlying uncertainty. Further, bootstrap truncated regressions with fixed factors are used to measure the impact of each model on the efficiency scores and to identify the most relevant contextual variables on efficiency. The proposed models have been demonstrated using an application in Mozambican banks to handle the underlying uncertainty. Findings reveal that fuzziness is predominant over randomness in interpreting the results. In addition, fuzziness can be used by decision-makers to identify missing variables to help in interpreting the results. Price of labor, price of capital, and market-share were found to be the significant factors in measuring bank efficiency. Managerial implications are addressed.
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There have been more and more words about climate change and global warming in the last few decades. But what do we really understand them? Is it logic that the climate change derived by human behaviour or is it an independent process of nature that occurs no matter how we try to stop it? Is the climate change a global warming or global cooling method? We know for sure that something is changing around us and we heard a million times that if we exhaust the resources of the Earth than we will cause permanent and irreversible damage. In the first part of this chapter we will see the facts. There will be a few different perspectives from a few different institutions publication about the methodology of measurement on climate change. In the second part of the chapter we shall distinguish how big part of the changes may be the results of the human activities, or is it even possible to distinguish what causes the climate change. In the last part of this chapter the IPCC’s scenario will be explained on the case if the process of the climate change can not be stopped, or if human kind does not do anything for mitigation.
Resumo:
Global warming16 has already begun. Climate change has become a self-propelling and self-reinforcing process as a result of the externality associated with greenhouse- gas (GHG) emissions. Although it is an externality related to humankind, according to a number of unique features we should distinguish it from other externalities. Climate change is a global phenomenon in its causes and consequences. The long-term and persistent impacts of climate change will likely continue over centuries without further anthropogenic mechanism. The preindustrial (equilibrium) level of GHG concentration in the atmosphere cannot be restored since it is irreversible, but if we do not stabilise the actual level of atmospheric concentration, the situation will become much worse than it is now. Assessing the impacts of climate change requires careful considerations because of the pervasive uncertainties and risks associated with it.
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A reálopciók a döntési rugalmasság megtestesítőiként jelen vannak a vállalatvezetők mindennapjaiban, és cégtől függően jelentős értéket képviselhetnek. Értékelésük a hagyományos diszkontált pénzáramlás módszerekkel csak korlátozottan lehetséges, ezért alternatívaként felmerül a pénzügyi opcióárazás módszertana, amelynek hagyományos változatai az alaptermék alakulásáról geometriai Brown-mozgást feltételeznek. A cikk ezt a feltevést veszi górcső alá a reálopciókra történő alkalmazás szempontjából, és megmutatja, hogy habár önkényesnek tűnhet, valójában nem pusztán egy matematikai szempontból kényelmes megoldás, hanem pénzügyileg is elfogadható feltétel. _______ Real options represent the fl exibility of decision-making, and are thus part of the everyday work of corporate executives, often having great value. Valuing them with the use of traditional Discounted Cash Flow models has limited relevance, therefore arises the alternative methodology of fi nancial option pricing, the traditional versions of which assume that the price of the underlying asset follows Geometric Brownian Motion. The paper examines this assumption from the aspect of real option valuation and shows that although it might seem arbitrary, it is not only a mathematically convenient choice, but also a fi nancially acceptable one.
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With the growing environmental crisis affecting our globe, ideas to weigh economic or social progress by the ‘energy input’ necessary to achieve it are increasingly gaining acceptance. This question is intriguing and is being dealt with by a growing number of studies, focusing on the environmental price of human progress. Even more intriguing, however, is the question of which factors of social organization contribute to a responsible use of the resources of our planet to achieve a given social result (‘smart development’). In this essay, we present the first systematic study on how migration – or rather, more concretely, received worker remittances per GDP – helps the nations of our globe to enjoy social and economic progress at a relatively small environmental price. We look at the effects of migration on the balance sheets of societal accounting, based on the ‘ecological price’ of the combined performance of democracy, economic growth, gender equality, human development, research and development, and social cohesion. Feminism in power, economic freedom, population density, the UNDP education index as well as the receipt of worker remittances all significantly contribute towards a ‘smart overall development’, while high military expenditures and a high world economic openness are a bottleneck for ‘smart overall development’.