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With rising price of oil and other conventional fuels, world is turning towards renewable energy to enable it to meet the growing demand for electrical power requirements. As an option, solar photovoltaic (PV) is gaining popularity, though its high initial cost is a major barrier for its widespread use. It can supply electricity, as stand alone grid connected and isolated PV hybrid energy systems. This paper discusses the techno-financial feasibility study for an electrical power supply system for a rural (island) village. The design tool HOMER was used as the sizing and optimization tool. Solar radiation and related load information are the input data required, and the procedure has been applied to the island community of Kohjig, located in the gulf of Thailand.

Provincial Electricity Authority (PEA) has a submarine cable project to Koh Tao in Surat Thani Province, Thailand to increase the capacity, stability and support the growing demand for electricity in Koh Tao due to a high economic growth rate. At present, Koh Tao uses electricity from diesel power plants resulting in high costs in maintenance, fuel, and electricity, causing PEA to bear many losses each year. Investment in the construction of a distribution system linked by submarine cable is a project that uses a lot of investment cost in constructions and in each construction also affects the environment as well. Thus, there must be an effective method of calculating the investment value to ensure that the investment projects are appropriate and cost-effective throughout the life of the asset. This paper presents the analysis of the financial feasibility of the submarine cable project to ensure that it will have economic benefits and be effective throughout the asset utilization period with life-cycle cost analysis. In this paper, three alternatives are simulated, and the life-cycle cost (LCC) of all three alternatives are calculated. Then, the analysis is performed to find which options are worth the most investment. Common network asset indices methodology (CNAIM) is applied to determine the age of the submarine cable used in the project. In addition, this method can be used to find the probability of failure (PoF) of the submarine cable which is an important parameter and is used to calculate in the LCC model to achieve the purpose of this paper.

The applications of anhydrous bioethanol to substitute or replace gasoline fuel have shown to attain benefits in terms of engine thermal efficiency, power output and exhaust emissions from spark ignition engines. A hydrous bioethanol has also been gained more attention due to its energy and cost effectiveness. The main aim of this work is to minimize fuel quantity injected to the intake ports of a four-cylinder engine under idle condition. The engine running with hydrous ethanol undergoes within lean-burn condition as its combustion stability is analyzed using an engine indicating system. Coefficient of variation in indicated mean effective pressure is an indicator for combustion stability with hydrocarbon and carbon monoxide emission monitoring as a supplement. Anhydrous ethanol burns faster than hydrous ethanol and gasoline in the uncalibrated engine at the same fuel-to-air equivalence ratio under idle condition. The leaner hydrous ethanol combustion tends to elevate the coefficient of variation in indicated mean effective pressure. The experimental results have found that the engine consumes greater hydrous ethanol by 10% on mass basis compared with those of anhydrous ethanol at the lean limit of fuel-to-air equivalence ratio of 0.67. The results of exhaust gas analysis were compared with those predicted by chemical equilibrium analysis of the fuel-air combustion; the resemble trends were found. Calibrating the alternative fueled engine for fuel injection quantity should be accomplished at idle with combustion stability and emissions optimization.

Abstract In this present work, green and efficient utilization concepts in the form of the use of an external magnetic field have been applied to improve catalytic performance in CO2 hydrogenation. The 10Fe 10Cu catalysts with two types of supports, core–shell and infiltrate mesoporous silica-aluminosilicate materials, were applied under external magnetic fields of different intensities (0, 20.8 mT, 27.7 mT) and orientations (north-to-south (N–S), south-to-north (S–N) directions). It was found that a magnetic field considerably enhanced both CO2 conversion and methanol and DME selectivities. The highest CO2 conversion was obtained over 10Fe 10Cu/infiltrate catalyst under the magnetic field conditions of 27.7 mT and 4N–S direction at 260 °C (conversion was 1.5 times greater than that without a magnetic field). Under such conditions and at 240 °C, the highest methanol and DME space time yields were obtained, with results 1.8–1.9 times higher than those of without a magnetic field. These excellent performances could be ascribed to the superior adsorption of CO2 and H2 reactant gas molecules over the surface of magnetized catalysts under external magnetic field. This leads to the advantages of the catalyzed CO2 hydrogenation–decreases in the operating temperature and simultaneous reduction in CO2 emission to the atmosphere. This therefore facilitates a carbon-neutral route of CO2 utilization.

AbstractSugarcane juice was spray-dried under various conditions to determine the most suitable drying conditions for the manufacture of sugarcane juice powder. Initially, fresh, 30°Brix and 50°Brix sugarcane juice samples were dried in a laboratory-scale spray dryer at an air-drying temperature between 130 °C and 170 °C using maltodextrin, Arabic gum and dietary fiber as drying aids. It appeared that sugarcane juice should be concentrated under vacuum to 30°Brix and added with at least 15% maltodextrin before drying at 170 °C in order to obtain dried powder product with a low drying cost. After conducting the experiments in the laboratory, sugarcane juice powders were produced in a factory using an industrial-scale spray dryer under five drying conditions. It was found that the energy cost of industrial-scale production of sugarcane juice powder ranged between 0.77 USD and 2.06 USD per kg of powder. According to the results of the industrial-scale experiments, the sugarcane juice powder should be produced using vacuum evaporation of the sugarcane juice to 30°Brix prior to adding maltodextrin at 30% by weight and then spray drying at 190 °C.

AbstractIn power system load flow studies, it is common to ignore wind park (WP) losses completely, since WPs are obliged to provide reactive power as a free‐of‐charge ancillary service. Strongly simplified WP loss estimations are also widespread. Prevailing loss modelling approaches may result in substantial and so far usually ignored reactive power allocation inefficiencies. The innovation of this paper lies in demonstrating this and in presenting an alternative modelling approach that combines speed, ease‐of‐use and accuracy.Calculations are based on a generic WP connected to 110 kV. It is simulated once using gearless permanent magnet synchronous generators and once using doubly fed induction generators. In this way, for the first time, the consequences of neglecting differences between wind generator types when calculating reactive power‐related losses are systematically quantified. Loss‐minimal dispatch is assessed using heuristic optimal power flow. Relevance of findings is demonstrated for the application of reducing system losses based on reactive power control of WPs in closed‐loop optimal power flow schemes. It is shown that non‐consideration of WP losses may lead to dispatch decisions where the increase in WP losses outweighs the achieved loss reduction in the 110 kV system by 400%. The study facilitates comparing reactive power ancillary services from WPs to that of other technologies from an economic perspective. It concludes by a benchmarking overview of pros and cons of modelling alternatives. Copyright © 2017 John Wiley & Sons, Ltd.

Economics Working Paper Series, 12/161

AbstractThe helical tidal current turbine was studied and reported its performance and characteristics for free water flow electric turbine development. The scale model of tidal turbine was built in dimension as: 0.5m and 0.6m of diameters and 1.25m in length; the turbine cross section blade was the symmetric NACA0020 with a 0.07m chord length, and there were 3 blades with the helical angle of 120o, 135o, and 150o. The model was tested in a towing tank (1.46m width, 3m depth and 45m length). The rotation and torque of the turbine was measured under various tow velocity settings, while power and power efficiencies under various tip speed ratios and helical angle velocities were presented. The characteristics obtained from this experiment provide useful information for the design and development of helical tidal current electrical turbine.