Fluid Dynamics Modelling of the Impact of Climate Change on Solar Radiation in Nigeria

Solar energy applications being developed to assist in limiting the extent of climate change through low-carbon technologies, rely on the natural environment that may be sensitive to changes in the climate, resulting from rising carbon emissions. Climate models are essential to predict the future of solar irradiance fields needed for long range planning of solar energy use. Despite the wide use of numerial models on precipitation and agriculture, their applications on measuring the effect of changing climate on renewable energy resources and weather parameters that contribute to building comforts are very sparse. In this study, the nature of seasonal and interannual variability of solar radiation is investigated alongside global solar radiation climatologies. The International Centre for Theoretical Physics regional climate model (ICTP-RegCM3) driven by European Centre/Hamburg 5 general circulation model (ECHAM5-GCM) and based majorly on the fundamental principles of Newton’s second law, the conservation of mass, the equation of state and the first law of thermodynamics was generated for Nigeria under an enhanced atmospheric CO2 level for the period 1981 to 2100. The model was validated using 11-year solar radiation and mean atmospheric temperature data from two observatories (Nigerian Meteorological Agency (NIMET) and the National Aeronautic and Space Administration (NASA)). Data were analysed using descriptive statistics and Fisher test (p<0.01). The model performed reasonably well when compared with the observed data. The best simulations for seasonal cycle of global solar radiation was obtained over the North having σ' = 1.45, R = 0.84 and σ' = 0.97, R = 0.98 whereas the worst simulations occur over the South with σ' = 0.93, R = 0.62 and σ' = 0.85 and R = 0.87 for the NIMET and NASA respectively. RegCM3 was also found to indicate a fair prediction of the interannual variability of solar radiation and mean air temperature over the climatic zones. Correlations for the solar radiation range from (NIMET) and (NASA) reflecting that the simulated interannual variability over the South and North climatic zones fairly agree with the observed, but more consistent with that observed in the Middle-belt zone . The simulated seasonal global solar radiation bias for the RegCM3 with NIMET and NASA observed datasets in the control period (1981–2010) are of similar magnitudes and showed a mixture of persistent positive and negative biases ranging between –10 and 30%. The seasonal potential future changes in period 1 (2011–2040), showed a reduction in the range of 0 (North) to 3.27% (South) whereas more reduction in global solar radiation is observed in period 2 (2041–2070), having general decrease ranging from 0.11 (Middlebelt) to 3.39% (South). Potential changes in period 3 (2071–2100), is generally characterized with mixed increase and decrease in global solar radiation across the country than the previous two periods. The model has predicted well, the potential effect of changing climate on solar radiation over Nigeria. It was also observed that the finer the resolution in grid spacing, the better the model in representing the observed data

Wind resources in North-East geopolitical zone, Nigeria: An assessment of the monthly and seasonal characteristics

This paper evaluates wind speed data of 37 years, 1971–2007 periods measured at 10m height for five meteorological stations in North-East geo-political zone, Nigeria, namely Bauchi, Nguru, Maiduguri, Yola and Potiskum that have been analyzed statistically to examine the monthly and seasonal variation of the wind characteristics. Wind data at 50m hub height were obtained by extrapolating the 10m data using the power law. The results proved Bauchi and Maiduguri to be the best sites among the five locations with monthly mean wind speeds ranging from 3.96 to 7.04 m/s and 4.49 to 6.10 m/s respectively while monthly average power density varies between 61.33–299.88W/m2 and 63.80–173.70W/m2 in that order, followed by Potiskum recording monthly mean wind speed ranging from 3.92 to 5.68 m/s coupled with an average power density between 53.82 and 150.84W/m2 in April and June. A Weibull distribution also gave a better fit than actual data while further investigations revealed higher wind speeds in the morning hours for Nguru, Maiduguri and Potiskum together with equal monthly periods of rainy and wet seasons whereas Bauchi and Yola are windier in the afternoon than morning periods with almost comparable months of rainy and dry seasons. Furthermore, wind availability shows that Maiduguri has wind speed above 4 m/s, 100% of the time in the two seasons while Bauchi, Nguru, Potiskum and Yola have approximately 80 and 100%, 50 and 50%, 75 and 75%, 50 and 50% periods of wind availability above 4 m/s in the dry and rainy seasons respectivel

Wind resource evaluation in six selected high altitude locations in Nigeria

This paper presents an assessment of wind energy potentials of six selected high altitude locations within the North-West and North-East geopolitical regions, Nigeria, by using 36-year (1971e2007) wind speed data subjected to 2-parameter Weibull distribution functions. The results showed that the maximum mean wind speed is obtained in Katsina as 9.839 m/s while the minimum value of 3.397 m/s is got in Kaduna for all the locations considered. The annual wind power density and energy variation based on the Weibull analysis ranged from 368.92 W/m2 and 3224.45 kWh/m2/year to 103.14 W/m2 and 901.75 kWh/m2/year in Kano and Potiskum for the maximum and minimum values respectively. Furthermore, Katsina and Kano will be suitable for wind turbine installations while Gusau will only be appropriate for wind energy utilization using taller wind turbine towers whereas Kaduna, Bauchi and Potiskum will be considered marginal for wind power development based of their respective annual mean wind speeds and power densities

Assessment of wind energy resources for electricity generation using WECS in North-Central region, Nigeria

This paper presents a statistical analysis of wind characteristics of five locations covering the North- Central (NC) geo-political zone, Nigeria, namely Bida, Minna, Makurdi, Ilorin and Lokoja using Weibull distribution functions on a 36-year (1971–2007) wind speed data at 10m height collected by the meteorological stations of NIMET in the region. The monthly, seasonal and annual variations were examined while wind speeds at different hub heights were got by extrapolating the 10mdata using the power law. The results from this investigation showed that all the five sites will only be adequate for non-connected electrical and mechanical applications with consideration to their respective annual mean wind speeds of 2.747, 4.289, 4.570, 4.386 and 3.158 m/s and annual average power densities of 16.569, 94.113, 76.399, 71.823 and 26.089W/m2 for Bida, Minna, Makurdi, Ilorin and Lokoja in that order. Weibull parameters k and c together with the energies for the respective locations were computed while further observation revealed that Bida, Minna, Makurdi and Ilorin are windier in the morning than afternoon periods for many months in a year whereas Lokoja had a windy afternoon. Additionally, four wind turbines De wind 48—600 kW, De wind D6—1250 kW, De wind D7—1500kW and De wind D8—2000kW were technically assessed for electricity generation by calculating their respective yearly energy output and capacity factor in all the locations

Study of Rake Face Action on Cutting Using Palm-Kernel Oil as Lubricant

The work investigates the effect of cutting speed, feed rate, depth of cut, and rake angle on main cutting force during the cylindrical turning of mild steel, brass, and aluminum rod, using high speed steel cutting tool and palm-kernel oil as cutting fluid. The impact of lubrication on the coefficient of friction between the chip and rake face during turning operation, assuming a negligible friction between the flank and cut surface is measured. Experimental results show that aluminum at cutting speed of 4.15m/s and rake angle 9o gave a 33.3% reduction in coefficient of friction while brass and mild steel under the same cutting condition gave7.9 and 13.8% increase in coefficient of friction respectively. Findings at cutting speed of 4.15m/s and depth of cut 1.5mm gave 9.79% reduction, 46.7 and 20.8% increase in coefficient of friction for brass, aluminum and mild steel respectively while cutting speed of 4.15m/s and feed 1.8mm/rev gave a 9.2% reduction, 30.4 and 14.5% increase in coefficient of friction for brass, aluminum and mild steel respectively. Similar trend was observed by varying the cutting conditions on the workparts through different selected values. The effect of palm-kernel oil as a metal cutting lubricant is more pronounced on aluminum than brass and mild steel

Potentials for Generating Alternative Fuels from Empty Palm Fruit Bunches by Pyrolysis

The threat that the disposal of empty palm fruit bunches constitute to communities in oil palm processing areas in Nigeria coupled with the current global focus on alternative energy is the trigger for this work. An existing pyrolytic reactor consisting of a reactor unit, condensate receiver, copper pipe connectors and gas receiver was modified and adapted for converting empty palm fruit bunches to alternative fuels. The average char yield was 44.9%, and the percentage of feedstock converted into pyrogas and tar oil was 55.1%. The char yield decreased gradually as temperature was increased from 300-700°C. Char yield was highest (39.78%) when the temperature was 300°C and the lowest char yield was 25.05% at 700°C The calorific values of char ranged between 21.12 and 23.76 MJ/kg. Apart from the potential of generating energy from pyrolysed EFB, it abates the disposal problem that EFB constitutes in the oil palm industry

Economics of wind energy utilisation for water pumping and CO2 mitigation potential in Niger Delta, Nigeria

The wind characteristics of six locations in Niger Delta, Nigeria, and the economics of the application of wind energy for water pumping and possible avoidable CO2 emissions through wind utilisation were examined. The wind data were measured at 10 m height and analysed using the two-parameter Weibull model. Small size wind turbines were accessed with Goulds 45J03 water pump series. The average power density, average energy density and annual energy across locations ranged between 6.28<_ APD <_ 102.90 W/M2, 4.49 <_AED <_ 82.96 kWh/m2 and 422<_AE <_ 747 kWh/m2/year, respectively. Bergey Excel-10 kW turbine had the lowest cost of energy and water pumping cost of 0.022 <_ COE <_ 0.151 $/kWh and 0.074 <_ WPC <_ 0.403$/m3, respectively. The annual capacity of water yield varies from 21,847 to 120,206 m3/year on a total dynamic head of 50 m. Furthermore, the annual diesel saved across the locations ranged from 1605 to 8696 l/year (17.47 to 94.67 GJ/year), while the annual averaged CO2 saved was between 4.32 and 22.93 tons/year

Small hydropower (SHP) development in Nigeria: An assessment

This paper evaluates small hydropower (SHP) development and examines the current situation in Nigeria with respect to the established policies and Energy Power Sector Reform (EPSR) Act 2005. Hydropower sector witnessed about 360% growth between 1971 and 2005 and yet only about 5% of the vast small hydropower (SHP) potential is tapped by the few plants built between 1923 and 1964. Operating and maintenance costs are in favor of SHP development in the country, being the lowest when compared with the situation in European countries. The Nigerian Government has taken steps to diversify energy sources in order to promote renewable energy development by encouraging private investments in the energy sector through reforms, but this may not be adequate as there remain barriers against SHP development in the country. It is concluded that government must incorporate subsidies, feed-in-tariffs, and framework for Price Purchase Agreements (PPA) into the policies in order to further promote renewable energy and attract both indigenous and foreign investments for quick adoption and rapid expansion of SHP technologie

Wind energy evaluation for electricity generation using WECS in seven selected locations in Nigeria

This paper statistically examine wind characteristics from seven meteorological stations within the North-West (NW) geo-political region of Nigeria using 36-year (1971–2007) wind speed data measured at 10 m height subjected to 2-parameter Weibull analysis. It is observed that the monthly mean wind speed in this region ranges from 2.64 m/s to 9.83 m/s. The minimum monthly mean wind speed was recorded in Yelwa in the month of November while the maximum value is observed in Katsina in the month of June. The annual wind speeds range from 3.61 m/s in Yelwa to 7.77 m/s in Kano. It is further shown that Sokoto, Katsina and Kano are suitable locations for wind turbine installations with annual mean wind speeds of 7.61, 7.45 and 7.77 m/s, respectively. The results also suggest that Gusau and Zaria should be applicable for wind energy development using taller wind turbine towers due to their respective annual mean speeds and mean power density while Kaduna is considered as marginal. In addition, higher wind speeds were recorded in the morning hours than afternoon periods for this region. A technical electricity generation assessment using four commercial wind turbines were carried out. The results indicate that, while the highest annual power is obtained with Nordex N80–2.5 MWas 14233.53 kW/year in Kano, the lowest is in Yelwa having 618.06 kW/year for Suzlon S52. It is further shown that the highest capacity factor is 64.95% for Suzlon S52–600 kW in Kano while the lowest is 3.82% for Vestas V80–2MW in Yelwa

Re-activation of a Small Hydropower(SHP)Plant: Oyan SHP Station,Nigeria

Electricity production in small hydropower (SHP) plants can be increased without the need for the construction of new SHP scheme, but by upgrading and optimizing different aspects of existing plant's operations. An assessment of the electromechanical equipment that suites the existing heads, discharge or flow rates and other electromechanical parameters at the Oyan SHP plant, using Retscreen Clean Energy Project Analysis Software and hydraulic turbine specific speed equation ( ) to evaluate plant performances was carried out in this work. Two cases involving upgrading of the electromechanical equipment to yield 10 and 12 MW of installed capacities respectively were considered, while at the same time maintaining the existing structures such as the weir, powerhouse and penstocks. The two cases were analysed and compared with a reference case (the existing installed capacity generation of 9 MW). Findings in terms of the financial and economic analysis for optimum installation and operation, favoured the 10 MW installation. Energy gain by installing the 10 MW is 33.37% relative to the reference case while the 12 MW is 5% compared with the reference. The simple payback for the 10 and 12 MW capacities is 11 and 13 months respectively. Hence, upgrade and optimization to 10 MW is found to be a more profitable option than the 12 MW capacity