Constitutive Modeling of Wind Energy Potential of Selected Sites in Nigeria: A Pre-Assessment Model

In this chapter, the authors present the result of a study carried out to develop a pre-assessment model that can be used to carry out a preliminary study on the availability of wind energy resources of a site. 21 years’ (1987 – 2007) monthly average wind speeds for 18 locations in Nigeria were used to create the simple constitutive model. The locations span across the six geopolitical zones of the nation with three stations from each zone. Various statistical procedures were employed in the development of the model. The outcome gave an empirical model, which if employed, will lead to determining the mod- est range of wind energy potential of a site. Further, the results from this model were compared with those from the well-established two-parameter Weibull statistical distribution function and found to be reasonably adequate. Thus with this model, decision on site selection for complete assessment can be made without much rigour

Assessment of Wind Power Potential and Wind Electricity Generation Using WECS of Two Sites in South West, Nigeria

The study was used to analyze the wind characteristics of Shaki (08.40’ N; 03.23’ E; Altitude 457.0 m; Air density 1.1723 kg/m3) and Iseyin (07.58’ N; 03.36’ E; Altitude 330.0 m; Air density 1.1869 kg/m3), two local sites in Oyo State, Nigeria. 21 years monthly mean wind speeds at 10 m height obtained from the Nigeria meteorological department were employed together with the Weibull 2-parameter distribution and other statistics to carry out monthly, seasonal and whole years’ analyses of the sites’ wind profiles for electricity generation. It was found that the whole data spread ranged between 0.9 and 9.1 m/s for the two sites while the 21 years’ average ranged between 3.2 and 5.1 m/s and 2.9 and 4.7 m/s for Shaki and Iseyin sites respectively. Three wind energy conversion systems were employed with the results and it was discovered that, the sites have capacity to generate MWh to GWh of electricity at an average cost/kWh of between € (0.025 and 0.049) and that a turbine with technical parameters of cut-in, cut-out and rated wind speeds of 3.0, 25 and 11.6 m/s is appropriate for the sites

Assessment of wind energy potential of two sites in North-East, Nigeria

The study is used to assess the wind energy potential of Maiduguri and Potiskum, two sites in North-East, Nigeria. 21 years (1987e2007) monthly mean wind data at 10 m height were assessed from the Nigeria Meteorological department and subjected to 2-parameter Weibull and other statistical analyzes. The result showed that average monthly mean wind speed variation for Potiskum ranged from 3.90 to 5.85 m/s, while for Maiduguri, it ranged from 4.35 to 6.33 m/s. Seasonally, data variation between the dry and wet seasons revealed that, the mean wind speed variation for Potiskum ranged from 4.46 (for dry) to 5.16 m/s (for wet), while for Maiduguri it ranged from 5.10 (dry) to 5.59 m/s (wet). The wind power density variation based on the Weibull analysis ranged from 102.54 to 300.15 W/m2 for Potiskum and it ranged from 114.77 to 360.04 W/m2 for Maiduguri respectively. Moreover, Maiduguri was found to be the better of the sites in terms of monthly and seasonal variation of mean wind speed, but they both can be suitable for stand alone and medium scale wind power generation

Wind Profile Characteristics and Econometrics Analysis of Wind Power Generation of a Site in Sokoto State, Nigeria

Abstract: This study assessed the viability of wind electricity production at a local meteorological site in Sokoto State, Nigeria. 21 years monthly mean wind speed data at 10 m height obtained from the Nigerian meteorological station were employed to carry out monthly, seasonal, yearly and whole years wind profile characteristics. The data were subjected to the Weibull 2-parameter and other statistical analyses. The econometrics analysis of wind electricity generation from the site was also studied using three wind turbine models of AV 928, V90 and SWT-3.6-107. The outcome showed that the wind speed data ranged from 2.4 to 12.1 m/s while the modal wind speed range was from 6.9 to 9.0 m/s. 98% of the data were found to be greater than 3.0 m/s and better potential exist for wind power generation in the dry season than in the wet. It was also discovered that potential exist for electricity generation of between 60.0MWh and 1.5GWh per month and between 2.1 and 10.8GWh per annum. The least cost of generating 1kWh of wind electricity with the turbine models at the site is estimated to be € 0.014. Key words: Wind power; Turbine cost; Cost per kWh; Weibull distribution; Sokoto; Nigeri

Wind Profile Characteristics and Econometrics Analysis of Wind Power Generation of a Site in Sokoto State, Nigeria

This study assessed the viability of wind electricity production at a local meteorological site in Sokoto State, Nigeria. 21 years monthly mean wind speed data at 10 m height obtained from the Nigerian meteorological station were employed to carry out monthly, seasonal, yearly and whole years wind profile characteristics. The data were subjected to the Weibull 2-parameter and other statistical analyses. The econometrics analysis of wind electricity generation from the site was also studied using three wind turbine models of AV 928, V90 and SWT-3.6-107. The outcome showed that the wind speed data ranged from 2.4 to 12.1 m/s while the modal wind speed range was from 6.9 to 9.0 m/s. 98% of the data were found to be greater than 3.0 m/s and better potential exist for wind power generation in the dry season than in the wet. It was also discovered that potential exist for electricity generation of between 60.0MWh and 1.5GWh per month and between 2.1 and 10.8GWh per annum. The least cost of generating 1kWh of wind electricity with the turbine models at the site is estimated to be € 0.014

MODELING OF THINLIQUID FALLINGFILM IN H2O-LiBr AND H2O-LiCl ABSORPTION REFRIGERATION SYSTEMS

Experimental modeling has over the past three decades been used in analyzing simultaneous heat and mass transfer in thin-liquid falling-film absorption processes. However, numerical modeling applications in this area have been minimal due to complications arising from the presence of waves. An approach in numerical modeling is to consider waves as a second order effect, thereby making it a smooth falling-film. The objective of this paper was to develop a numerical model for the absorption process on a thin-liquid smooth falling-film using lithium bromide (LiBr) and lithium chloride (LiCl) solutions. The absorption process of a thin-liquid smooth falling-film was considered as a two-dimensional steady laminar flow within the film thickness to the absorber wall. The conservation equations were used to determine temperature and concentration distribution within the film-thickness using the finite difference technique. Existing data on LiBr and LiCl solutions in the literature were used to validate the developed model. Standard values of absorber wall length, film thickness, solution mass flow-rate, absorbent inlet concentration, inlet temperature, absorber wall temperature, conventional film Reynolds number and absorption design effectiveness were used for both LiBr and LiCl solutions. Data were analyzed using descriptive statistics and student’s t-test (p<0.05). The physical properties distribution for both LiBr and LiClsolutions were not significantly different from published results available in the literature(p<0.05). The nodal temperature distribution obtained within the film thickness both in the bulk and interface between the liquid and vapour regions were between 44.4 and 35.0oC while concentration was between 60.0 and 54.5% for LiBr-H2O. Similarly for LiCl-H2O, the model temperature distribution was between 35.0 and 30.0oC while the concentration was between 45.0 and 35.8%.A numerical model on a thin-liquid smooth falling film using LiBr and LiCl solutions was developed. Lithium bromide was also observed to have higher concentration values than lithium chloride thus suggesting a better working fluid combination especially in the absorption air-conditioning system

Performance evaluation and economic analysis of a gas turbine power plant in Nigeria

In this study, performance evaluation and economic analysis (in terms of power outage cost due to system downtime) of a gas turbine power plant in Nigeria have been carried out for the period 2001–2010. The thermal power station consists of nine gas turbine units with total capacity of 301 MW (9 � 31.5 MW). The study reveals that 64.3% of the installed capacity was available in the period. The percentage of shortfall of energy generated in the period ranged from 4.18% to 14.53% as against the acceptable value of 5–10%. The load factor of the plant is between 20.8% and 78.2% as against international best practice of 80%. The average availability of the plant for the period was about 64% as against industry best practice of 95%, while the average use factor was about 92%. The capacity factor of the plant ranged from 20.8% to 78.23% while the utilization factor ranged from 85.47% to 95.82%. For the ten years under review, there was energy generation loss of about 35.7% of expected energy generation of 26.411 TW h with consequent plant performance of 64.3%. The study further reveals that the 35.7% of generation loss resulted in revenue loss of about M$251 (approximately bN40). The simple performance indicator developed to evaluate the performance indices and outage cost for the station can also be applicable to other power stations in Nigeria and elsewhere. Measures to improve the performance indices of the plant have been suggested such as training of operation and maintenance (O & M) personnel regularly, improvement in O & M practices, proper spare parts inventory and improvement in general housekeeping of the plant. From technical point of view, performance of the plant can be improved by retrofitting with a gas turbine air inlet cooling system, heat recovery system or adding modifications (inter-cooling or regeneration) to the simple gas turbine units

Wind Profile Characteristics and Turbine Performance Analysis in Kano, North-western Nigeria

This study analyzed the electricity generation potential from wind at Kano, Nigeria (12.05°N; 08.2°E; altitude 472.5 m; air density 1.1705 kg/m3). Twenty one years (1987 to 2007) monthly mean wind speed data at a height of 10 m were assessed from the Nigeria Meteorological Department, Oshodi. The data were subjected to different statistical tests and also compared with the two-parameter Weibull probability density function. The outcome shows that the average monthly wind speed ranged from 6.6 to 9.5 m/s. Seasonally, average wind speeds ranged between 6.6 to 8.5 m/s and 7.4 to 9.5 m/s for dry (October to March) and wet (April to September) seasons, respectively. Also, estimated monthly wind power ranged between 3.6 and 12.5 MWh/m2. The most probable and maximum energy carrying wind speeds were also determined and the two parameters of the Weibull statistics were found to lie between 2.1 ≤ k ≤ 4.9 and 7.3 ≤ c ≤ 10.7, respectively. These results indicate that wind speeds at Kano may be economically viable for wind-to-electricity at and above the height of 10 m. In addition, five practical turbine models were assessed for the site’s wind profile, with results suggesting strong economic viabilit

WIND ENERGY POTENTIAL FOR POWER GENERATION OF A LOCAL SITE IN GUSAU, NIGERIA

This study was used to evaluate the wind energy potential of a meteorological site in Gusau, the capital city of Zamfara state, in Nigeria. Twenty-one years (1987−2007) of three-hourly monthly mean wind data from the Nigeria Meteorological Department were assessed and subjected to two-parameter Weibull and other statistical analyses to determine the resource potential of the site for periods of months, seasons, and years. Attempts were made to compare the mean measured data with estimated data, and the Kolmogorov-Smirnov statistics were employed to show the site's wind profile's consistence with Weibull two-parameter distribution. The results showed that the monthly values of k and c ranged between 3.9 ≤ 7.9 and 4.0 ≤ 8.3, respectively, with over 80% of all the data having values ranging between 5 and 10 m/s or more. Most probable and maximum energy-carrying wind speeds also were found to be between 3.7 and 7.7 m/s and 4.5 and 9.3 m/s, respectively, across the period. Estimated wind power densities also ranged from 69.0 (in October) to 626.2 W/m2 (in January) at 10 m height. Seasonally, the dry season experiences higher wind speeds and the period of highest wind energy harvest could be from January to June every year