Current Issue : January - March Volume : 2012 Issue Number : 1 Articles : 8 Articles
Environmental and Economic load dispatch are important optimization task in power system operation for allocating generation among the committed units such that the constraints imposed are satisfied and the energy requirement in terms of different variance .In this paper we try to reduce emission and fuel costs for the power generation by proper load dispatch schedule by selection of our object. So the overall Emission or costing of operation of power system can be reduced. We mainly try to reduce emission of NO2, CO2 and SO2 gases by the load dispatch scheduling and selection of the object which we have to minimize. We have developed MATLAB program based on our requirement. MATLAB program is used to achieve above requirement and arrange generation plant according to the program out put for the efficient operation of the power system....
A new way of connecting PV sources to adaptive voltage active power filter (AV APF) has been compared with classic approach including active power filter (APF). In standard active power filter applications a relatively high DC link voltage (500?V or even more) with a buck converter or lower voltage (approx. 100?V) with boost converter can be used. These two converters appear also in adaptive voltage circuit of AV APF, but in this case it is possible to achieve many different connections of DC source. Benefit of this approach is that the same circuit is used for improving switching conditions in APF and for connection of solar cells. It appears that these two functions support each other and a large variety of DC voltages and currents can be connected to AC mains. Experimental results confirm expectations of increased energy transfer from additional DC source to network, especially for DC voltages being lower than DC link voltage....
Algae are believed to be a good source of renewable energy because of their rapid growth rate and their ability to be cultivated in waste waters or waste land. The algae Nannochloropsis sp. was chosen for this study, where lipids were extracted and transesterified for biodiesel production. The FFA (free fatty acid) content in the lipid was estimated to be 27wt% of the total fatty acids. The remaining biomass after lipid extraction was pyrolyzed at 200?C, 300?C, and 400?C to produce solid, liquid, and gas products.The GC/MS showed that the lipids of Nannochloropsis sp. consist of high concentration of polyunsaturated fatty acids (29wt%), eicosapentaenoic acid. The bio-oil produced from pyrolysis of algae biomass (after lipid extraction) at 300?C was composed of 50wt% acetone, 30wt% methyl ethyl ketone and 19wt% aromatics such as pyrazine and pyrrole. The heating value of bio-oil is 32 MJ/kg of oil....
Wood and other nonwood lignocellulosic materials are renewable natural resources useful for different applications based on end users' preference. Their use for generating energy, an application that has not been outmoded, has been noted to be increasing worldwide owing to multifarious reasons. Therefore, there has been the need for studies with results targeted at sustainable ways by which they can be sourced for this and other purposes, as this source of energy is currently still relevant particularly in the developing world. Agroforestry techniques that are based on realisable concepts acceptable to stakeholders have been suggested for this purpose. These age-long techniques are adopted for different purposes with incorporated components partly dependent on native intelligence, indigenous/traditional knowledge, and/or users' perspectives and expected outputs. Since wood and other lignocellulosic biomass can be obtained using these production techniques, optimising their potentials in this regard will be beneficial. This paper was therefore focused on the increasing trend in global wood fuel consumption and studies aimed at contributing to improvement of agroforestry systems as sustainable sources of wood fuel, a renewable source of energy....
Thermal properties of humans were studied in the case where a small-size energy scavenger is placed on the body. In such a case, the human being serves as a heat source for the thermopile of the scavenger, but the latter serves as a thermally insulating object. As a result, the body properties, namely, the skin temperature, heat flow, and thermal resistance locally change. This is the result of redirection of heat flow inside the body to colder zones because of thermal insulation provided by the scavenger. Increased thermal resistance of human body, in turn, affects the design of the scavenger. The analysis of such scavenger performed for ambient temperatures of 0�°C to 25�°C shows that it could reach competitive performance characteristics and replace batteries in low-power wearable electronics. A simulated power of up to 60?�µW/cm2 at 0�°C has been validated by using wearable thermoelectric modules....
Energy is one of the major inputs for the economic development of any country. In the case of developing countries, the energy sector assumes critical importance in view of the ever increasing energy needs requiring huge investment to meet them. The consumption of energy increasing at a fast pace while available resources remain limited. The global need for energy is increasing on an average by about 1.5 % every year. Out of the total amount of primary energy around 80 % comes from fossil fuels. The current consumption of fossil fuels particularly oil is not sustainable in the long term. Energy conservation was not a part of National energy policy until the 1970. However the need for the such approach felt after the oil price hike and its deterious effect on the economy....
Modeling and optimization of a residential solar-powered stand-alone power system comprising photovoltaic (PV) arrays and secondary batteries are presented. Moreover, an economic study is performed to determine the cost of electricity (COE) produced from this system so as to determine its competitiveness with the conventional sources of electricity. All of the calculations are performed using a computer code developed by using MATLAB. The system output was calculated for Cairo city (30�°01'N, 31�°14'E) in Egypt. It was found that dual-axis solar tracking is not economically feasible while cooling of the PV surface helps to lower the COE of the system. Also, the average maximum efficiency of the modeled 200?W solar cells was 14.16%. The system which has an efficiency of 12% showed a great ability to satisfy the estimated demand load. The COE obtained from the system was found to be 41.7?cents/kWh over 20 years of its operation with an expected future cost of 31?cents/kWh....
Wind and solar (photovoltaic) power generations have rapidly evolved over the recent decades. Efficient and reliable planning of power system with significant penetration of these resources brings challenges due to their fluctuating and uncertain characteristics. In this paper, incorporation of both PV and wind units in the unit commitment of power system is investigated and a risk-constrained solution to this problem is presented. Considering the contribution of PV and wind units, the aim is to determine the start-up/shut-down status as well as the amount of generating power for all thermal units at minimum operating cost during the scheduling horizon, subject to the system and unit operational constraints. Using the probabilistic method of confidence interval, the uncertainties associated with wind and PV generation are modeled by analyzing the error in the forecasted wind speed and solar irradiation data. Differential evolution algorithm is proposed to solve the two-stage mixed-integer nonlinear optimization problem. Numerical results indicate that with indeterminate information about the wind and PV generation, a reliable day-ahead scheduling of other units is achieved by considering the estimated dependable generation of PV and wind units....
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