EXPERIMENTAL INVESTIGATION OF A CONCEPT WAVE ENERGY CONVERTER FOR HARNESSING LOW AMPLITUDE SEA WAVES

This paper presents the results from experimental validation of numerical simulation of a concept wave energy converter for low amplitude sea waves. The device was conceived to contain a wave amplifying device (WAD) to magnify the wave height of incident waves while point absorber buoy(s) efficiently harness the wave energy for electricity production. The validation results show that the optimum aperture angle for the WAD is 45±2 degree, and wave height magnification of 170% is possible. The optimal buoy shape for the device was confirmed as concave wedge buoy. The combination of the two in a single device shall make economical the harnessing of low amplitude waves

EXPERIMENTAL INVESTIGATION OF A CONCEPT WAVE ENERGY CONVERTER FOR HARNESSING LOW AMPLITUDE SEA WAVES

This paper presents the results from experimental validation of numerical simulation of a concept wave energy converter for low amplitude sea waves. The device was conceived to contain a wave amplifying device (WAD) to magnify the wave height of incident waves while point absorber buoy(s) efficiently harness the wave energy for electricity production. The validation results show that the optimum aperture angle for the WAD is 45±2 degree, and wave height magnification of 170% is possible. The optimal buoy shape for the device was confirmed as concave wedge buoy. The combination of the two in a single device shall make economical the harnessing of low amplitude waves

INVESTIGATING POINTS-OF-GENERATION POWER LOSSES ON THE NIGERIAN NATIONAL GRID FOLLOWING UNBUNDLING OF THE ELECTRIC UTILITY INDUSTRY

Aside from the domino effects of being radial in structure, the Nigerian national electric grid is currently suffering from deteriorated infrastructures and unpredictable fuel supply for power generation. Massive introduction of green energy-based microgrid alternatives has been proposed as a major means of resolving the challenges. Such paradigm shift needs to be substantiated within the context of the present situation of the grid, for the consumption of policy makers and implementers, hence; the performance of the generation sub-system of the grid in the post-deregulation era is evaluated in this study. Two-year numerical data on the operational capacities of the twenty-nine power plants that are currently connected to the grid are employed to profile the behaviours of the plants over the period. Yearly averages of the three operational capacities of each plant are estimated, and by comparing the respective capacities, generation losses are computed for each of the plants. With 5,063.8 MW yearly average generation capacity in the year 2018, a loss of 61.02 % was experienced on the sub-system; while the generation loss was 61.55 % in the year 2019 that has yearly average generation capacity of 5,062.5 MW. For the two years combined, the average generation capacity is 5,063.2 MW at 61.36 % power loss. These estimations reveal that the pre-deregulation loss profile of the generation sub-system has not been curtailed despite the unbundling of the electric power industry. Generation loss has rather persisted and keeps taking a heavy toll on the electric utility market of the country. Significant deployment of renewable electricity microgrid is therefore required to provide enduring solution

EXPERIMENTAL INVESTIGATION OF A CONCEPT WAVE ENERGY CONVERTER FOR HARNESSING LOW AMPLITUDE SEA WAVES

This paper presents the results from experimental validation of numerical simulation of a concept wave energy converter for low amplitude sea waves. The device was conceived to contain a wave amplifying device (WAD) to magnify the wave height of incident waves while point absorber buoy(s) efficiently harness the wave energy for electricity production. The validation results show that the optimum aperture angle for the WAD is 45±2 degree, and wave height magnification of 170% is possible. The optimal buoy shape for the device was confirmed as concave wedge buoy. The combination of the two in a single device shall make economical the harnessing of low amplitude waves

Transient stability based dynamic security assessment indices

As power systems become increasingly stability constrained, the need for dynamic security assessment (DSA) becomes important. However, the resources and technology required to achieve on-line DSA at reasonable cost for utility companies are not easily come by. Therefore, an offline method is needed to examine and screen all likely contingencies to determine those that may lead to instability. Some indices and techniques have been proposed to tackle this problem but are mostly for small disturbances which are not really threats when timely cleared. Some methods are based on evolutionary computation which comes with a lot of drawbacks as there is no guarantee of finding optimal solutions within a finite time and parameter tuning are mostly by trial-and-error. In this paper, a simpler approach to power system DSA indices is proposed using time domain transient stability analysis simulations. A conventional power system which synchronous machines are modeled with two-axis dynamic model, and modeled by Differential and Algebraic Equations, is used and solved numerically taken advantage of MATLAB ODE solver. The proposed indices are tested by carrying out N − 1 contingency on the transmission network of an IEEE 57-Bus test system to determine contingency cases that are likely to lead to system instability. The indices are validated by comparing their results with those obtained through an established DSA index called Angle Index in literature. Finally, effects of synchronous machine models on the indices are tested by comparing the results of the proposed functions with those obtained through synchronous machine classical model

Hazardous Organic Pollutants from Open Burning of Municipal Wastes in Southwest Nigeria

The Southwest Nigeria has witnessed tremendous increase in output of municipal wastes in the recent years. Non availability of government policy on solid wastes management or its lack of effectiveness where it exists makes unabated open burning the predominant means of municipal solid waste disposal in the region. Open burning of municipal wastes being a major source of anthropogenic air emissions was investigated for atmospheric loading of some hazardous organic pollutants using emission inventory method. The specific pollutants considered in this study were volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo –p- dioxin (PCDDs) and polychlorinated dibenzo furan (PCDF). The estimated release of VOCs, PAHs, PCBs, PCDD and PCDF from open burning of municipal wastes in the region over the 5- year period investigated were 64000 tonnes, 988 tonnes, 43 tonnes, 0.56 tonnes and 0.2 tonnes respectively. Giving the serious human health implications associated with these hazardous organic pollutants, the study suggested conversion of wastes to energy as a possible solution since the region also has energy challenges

Design validation of a laboratory-scale wind turbine emulator

Presented in this study is an investigation of the real-time performance of a laboratory-scale model of wind turbine emulator. Developed to provide a cost-effective experimental facility for demonstrating and validating wind energy conversion systems at new wind territories, the emulator comprises a software component with a hardware interface of a motor-driven wound rotor induction generator. A real-life wind speed profile is implemented on the model to investigate its performance under a near-real-world scenario and, some operational characteristics of real wind energy conversion systems are exactly replicated by the emulator in the course of the experimentation. The emulator could therefore be considered suitable for use as a laboratory level testbed for the demonstration and validation of wind energy conversion systems in the real-time

Agro-residues for clean electricity: A thermo-property characterization of cocoa and kolanut waste blends

Huge quantities of harvest wastes that are generated from agricultural practices at every farming season in Nigeria are not put into significant use. As an attempt towards adopting these abundant by-products as bioenergy resources for electricity generation, yearly quantities of both cocoa and kolanut harvest residues were estimated in this study. Hygroscopic natures and moisture contents of the two, and their blends, were also analyzed and compared. It was estimated that approximately 681,000 tons and 90,000 tons of cocoa and kolanut husks respectively, are produced in the country annually. While the proximate analyses showed that the sample made of 100% cocoa waste had the least volatile matter and moisture contents in addition to having highest fixed ash and fixed carbon contents, the reverse was the case with the sample made of 100% kolanut waste composition. From the ultimate analyses, however, the latter appears to possess the best characteristic (highest hydrogen and least oxygen contents), but its highest nitrogen content is a pointer to its exhibition of poor thermal property. The gross calorific contents of the samples were, therefore employed for definitive determination of their thermoelectric potentials and these gave higher heating values of 15.19 MJ/kg and 13.87 MJ/kg respectively, with the blends having their values within this range in proportionality to the mass percentage of kolanut husk in the blends. In addition to the two wastes exhibiting good energy characteristics, the study concludes that their blending offers benefit of reduction in ash content. At the optimal blend of equal composition of the two materials (50%CPH/50% KPH), it was estimated that 29,000 MW of electricity is accruable from the wastes