Impact of Sunshine Duration and Clearness Index on Diffuse Solar Radiation Estimation in Mountainous Climate

In this paper, measured data of solar radiation was applied to develop forty-three (43) empirical models for estimation of monthly average diffuse solar radiation using clearness index, sunshine duration and a combination of them as predictors. The data covered a period of two years from May 2015 to April 2017 and was measured at Mehran University of Engineering and Technology, Hyderabad, Pakistan. Through a comprehensive statistical performance analysis, 43 dimensional models developed were tested for constructing the most accurate regression model to predict the monthly mean daily diffuse solar radiation in Hyderabad, Pakistan. On the whole, the model 42 – a hybrid of sunshine duration and clearness index predictors of diffuse fraction outperformed the remaining models proposed in this study. The best model (model 42) was then compared with 5 models and 5 measured data of diffuse solar radiation available in the literature and the NASA database by applying statistical indicators such as MBE, MPE, RMSE, RRMSE, R2 and GPI. Through the analysis, the hybrid of sunshine duration and clearness index predictors of diffuse fraction model (model 42) was selected as the most appropriate model. The study concluded that the proposed hybrid model can serve as a baseline for the design of photovoltaic systems and estimate the monthly mean daily diffuse solar radiation on the horizontal surface for Hyderabad, Pakistan and other locations with similar local climate conditions.Citation: Nwokolo, S.C. and Otse, C.Q. (2019). Impact of Sunshine Duration and Clearness Index on Diffuse Solar Radiation Estimation in Mountainous Climate. Trends in Renewable Energy, 5, 307-332. DOI: 10.17737/tre.2019.5.3.0010

A Global Review of Empirical Models for Estimating Photosynthetically Active Radiation

A good working knowledge of photosynthetically active radiation (PAR) is of vital requirement for determining the terrestrial photosynthesis, primary productivity calculation, ecosystem-atmosphere carbon dioxide, plant physiology, biomass production, natural illumination in greenhouses, radiation climate, remote sensing of vegetation, and radiation regimes of plant canopy, photosynthesis, productivity models of vegetation, etc. However, routine measurement of PAR is not available in most location of interest across the globe. During the past 77 years in order to estimate PAR on hourly, daily and monthly mean basis, several empirical models have been developed for numerous locations globally. As a result, numerous input parameters have been utilized and different functional forms applied. This study was aim at classifying and reviewing the empirical models employed for estimating PAR across the globe. The empirical models so far utilized were classified into ten main categories and presented base on the input parameters applied. The models were further reclassified into numerous main sub-classes (groups) and finally presented according to their developing year. In general, 757 empirical models, 62 functional forms and 32 groups were reported in literature for estimating PAR across the globe. The empirical models utilized were equally compared with models developed using different artificial neural network (ANN); and the result revealed that ANN models are more suitable for estimating PAR across the globe. Thus, this review would provide solar energy researchers with input parameters and functional forms that have been widely used to up to date, and recognizing their importance in estimating PAR globally. Citation: Nwokolo, S. C., and Amadi, S. O. (2018). A Global Review of Empirical Models for Estimating Photosynthetically Active Radiation. Trends in Renewable Energy, 4(2), 236-327. DOI: 10.17737/tre.2018.4.2.007

Global Solar Radiation Characteristics at Calabar and Port Harcourt Cities in Nigeria

This study analyzed the inter-annual variability in solar radiation at Port Harcourt and Calabar, aiming at improving knowledge of solar resources. For the investigation, monthly mean global solar radiation data for fifteen years (2000 – 2014) was collected from Nigerian Meteorological Agency (NIMET), and the monthly mean extraterrestrial solar radiation was determined using globally recognized standard relation. The clearness index parameter was employed for characterizing the spatial variability of solar radiation for Calabar and Port Harcourt. The statistics of the monthly mean solar radiation deviations of Port Harcourt and Calabar was tested using the Kolmogorov–Smirnov method. The test results showed that they are normally distributed random variables. Furthermore, the analysis of sequential properties showed that the coefficients of the auto-correlation with lag 1 are significant for both stations. The auto-correlation coefficients with lag 1, though usually not significant, are negative for both stations. The auto regression lag 1 (AR-1) is the recommended procedure (model equation) for generating monthly solar radiation synthetic time series, with auto-correlation coefficients varying from 0.30 to 0.47 for both stations in the South-South of Nigeria.Citation: Amadi, S. (2020). Global Solar Radiation Characteristics at Calabar and Port Harcourt Cities in Nigeria. Trends in Renewable Energy, 6, 101-120. DOI: 10.17737/tre.2020.6.2.0011

A review of regression models employed for predicting diffuse solar radiation in North-Western Africa

The knowledge of diffuse solar radiation (Hd) is of almost importance for determining the gross primary productivity, net ecosystem, exchange of carbon dioxide, light use efficiency and changing colour of the sky. However, routine measurement of Hd is not available in most locations in North-Western Africa. During the past 36 years in order to predict Hd in the horizontal surface on hourly, daily and monthly mean basis, several regression models have been developed for numerous locations in North-Western Africa. As a result, several input parameters have been utilized and different functional forms applied. The regression models so far utilized were classified into six main categories and presented based on the input parameters applied. The models were further reclassified into numerous main groups and finally represented according to their developing year. In general, 188 regression models, 33 functional forms and 20 groups were reported in literature for predicting Hd in North-Western Africa. The regression and soft computing models developed within North-Western Africa and across the globe were examined in order to determine the best technique of prediction. The result revealed that soft computing models are more suitable for predicting Hd in North-Western Africa and across the globe. Citation: Ogbulezie, J., Ushie, O., and Nwokolo, S. (2017). A review of regression models employed for predicting diffuse solar radiation in North-Western Africa. Trends in Renewable Energy, 3(2), 160-206. DOI: 10.17737/tre.2017.3.2.004

Effects of age variance on repeatability estimates of egg dimensions of Bovan Nera Black laying chickens

AbstractThe present research was designed to examine the effects of age variance on repeatability estimates of egg length, egg breadth and egg shape index of Bovan Nera Black laying chickens at 25, 51, 72weeks and combined ages of the bird. For this purpose thirty birds were selected from the flock of layers in the Babcock University Teaching and Research Farm. They were individually housed in labeled separate battery cage. A total of thirty (30) eggs were collected daily from the birds continuously for five (5) days of egg production, at each age of 25, 51 and 72weeks. The total number of eggs collected at each age were 150 and 450 for the total of three age periods. Data were collected on egg production traits for egg length, egg breadth and egg shape index. These data were subjected to statistical analysis using Completely Randomized Design. General linear model procedure of statistical analytical system (SAS) was used to obtain the variance components for the estimation of repeatability. Moderate repeatability estimates were obtained when the age variance was included in the computation and low estimates were registered when the age variance was excluded from the computation. The repeatability estimates from different egg quality traits were low to high. Since most of the traits recorded low repeatability values, these traits can be improve by mass selection thereby culminating into egg production with optimal quality

Assessing the Impact of Soiling, Tilt Angle, and Solar Radiation on the Performance of Solar PV Systems

This research examined the observed datasets and a theoretically derived model for estimating yearly optimum tilt angle (β), maximum incident solar radiation (Hmax), clean gain indicator (CGI), and soiling loss indicator (SLI) at Mumbwa, Zambia, the Mediterranean Region, and low latitude locations across the globe. The cleaned tilted collector emerged as the best performing collector due to Hmax and much higher energy gains compared with the soiled collector. CGI showed an appreciable performance of 0.4737% over -0.4708% on the SLI, indicating that soiling on the surface of photovoltaic (PV) modules significantly depreciates the overall performance of PV modules. Two established empirical models obtained from the literature were compared with the established theoretical model (β=φ). The result revealed that the two models overestimated the observed annual optimum tilt angle in this paper, simply because the models were developed with high latitude location datasets from the Asia continent. However, the newly established monthly and yearly global radiation indicator (GRI) models by the authors in their previous paper performed excellently in the selected representative cities in the Mediterranean region.Citation:

Exploring Cutting-Edge Approaches to Reduce Africa's Carbon Footprint through Innovative Technology Dissemination

This paper investigates the possibility of revolutionizing Africa's carbon footprint through innovative technology dissemination strategies for GHG emission reduction.  It highlights the importance of harnessing renewable energy sources to mitigate climate change and promote sustainable development in Africa. This paper also examined several technology diffusion theories in order to unleash Africa's climate-smart potential by tying them to the recommended techniques for dealing with technological diffusion concerns. These theories varied from diffusion of innovation theory to planned behaviour theory. By analysing these theories, it was found that the most appropriate technology diffusion theory for the assessment of innovative technology dissemination strategies for GHG emission reduction in Africa would be the Diffusion of Innovations Theory. This is due to the theory's emphasis on the dissemination and adoption of new ideas, technologies, or innovations by people or groups within a social system. It would give useful insights into the variables influencing the adoption and dissemination of novel technology for reducing GHG emissions in Africa. The paper also discusses the challenges and barriers faced in the diffusion of renewable energy technologies across the continent while proposing innovative strategies to overcome these obstacles and unlock Africa's untapped climate-smart potential. These strategies include promoting policy and regulatory frameworks that incentivize investment in renewable energy, fostering partnerships between governments, private sector entities, and international organizations to support technology transfer and capacity building, and implementing financial mechanisms such as green bonds and carbon pricing to mobilize funding for renewable energy projects. These proposed strategies were also used to develop seven policies required for innovative technology dissemination strategies for GHG emission reduction in Africa. These policies aim to address the unique challenges faced by African countries in adopting and implementing innovative technologies for GHG emission reduction. By focusing on capacity building, financial incentives, and knowledge sharing, these strategies seek to promote the widespread adoption of sustainable technologies across the continent. They emphasize the importance of collaboration between governments, private sector entities, and international organizations to ensure the successful implementation and long-term sustainability of these policies.Citation: Nwokolo, S. C., Eyime, E. E., Obiwulu, A. U., & Ogbulezie, J. C. (2023). Exploring Cutting-Edge Approaches to Reduce Africa's Carbon Footprint through Innovative Technology Dissemination. Trends in Renewable Energy, 10, 1-29. doi:10.17737/tre.2024.10.1.0016

Effects of Angstrom-Prescott and Hargreaves-Samani Coefficients on Climate Forcing and Solar PV Technology Selection in West Africa

We evaluated and compared the performance of simulated Angström-Prescott (AP) and Hargreaves-Samani (HS) models on monthly and annual timescales using generalized datasets covering the entire West African region. The fitted AP model yielded more efficient parameters of a = 0.366 and b = 0.459, whereas the HS model produced a 0.216 coefficient based on an annual timescale, which is more suitable in the region compared to coefficients recommended by the Food and Agriculture Organization (FAO) (a = 0.25 and b = 0.5) and HS (0.17), respectively. Employing the FAO and HS recommended coefficients will introduce a relative percentage error (RPE) of 18.388% and 27.19% compared to the RPEs of 0.0014% and 0.1036% obtained in this study, respectively. When considering time and resource availability in the absence of ground-measured datasets, the coefficients obtained in this study can be used for predicting global solar radiation within the region. According to the AP and HS coefficients, the polycrystalline module (p-Si) is more reliable than the monocrystalline module (m-Si) because the p-Si module has a higher tendency to withstand the high temperatures projected to affect the region due to its higher intrinsic properties based on the AP and HS coefficients assessment in the region.Citation: Agbor, M. E., Udo, S. O., Ewona, I. O., Nwokolo, S. C., Ogbulezie, J. C., Amadi, S. O., and Billy, U. A. (2023). Effects of Angstrom-Prescott and Hargreaves-Samani Coefficients on Climate Forcing and Solar PV Technology Selection in West Africa. Trends in Renewable Energy, 9, 78-106. DOI: 10.17737/tre.2023.9.1.0015

Credible Pathways to Catching Up with Climate Goals in Nigeria

This paper seeks to address Nigeria’s challenges in meeting its climate objectives by investigating feasible pathways that can be implemented to accelerate progress and ensure credibility in meeting these targets. By examining the current policies and practices in place as well as successful strategies employed by other countries, this paper aims to provide strategies and policy implications recommendations for Nigeria to enhance its climate action efforts. The potential scenarios developed in this study ranged from increasing renewable energy capacity to implementing stricter regulations and standards for industries to reduce their carbon footprint, promote sustainable production processes, and strengthen climate governance and policy frameworks. The authors further investigated these measures and discovered that implementing stricter regulations and standards for industries would reduce their carbon footprint, promote sustainable production processes, and strengthen climate governance and policy frameworks. As such, Nigeria will be able to meet its climate goals more quickly as a result of the following factors: preventing environmental degradation, funding environmentally friendly infrastructure, and improving public transportation systems that can reduce vehicle-related greenhouse gas emissions. The authors developed policy measures based on the proposed twelve credible pathways to catching up with climate goals in Nigeria, thereby promoting faster progress by the Nigerian government in achieving climate goals. By adopting these measures, Nigeria’s progress toward the proposed zero net by 2060 will be significantly accelerated. It will position Nigeria as a continental leader in sustainable development and contribute to the overall global efforts to mitigate climate change. This will not only benefit the environment but also lead to financial development and an improved standard of living for its citizens

Heritability estimates of external egg quality traits of Exotic Laying Chickens under the influence of age variance in the tropics

The present research was designed to examine heritability estimates of egg length, egg breadth and egg shape index under the influence of age variance for Bovan Nera Black laying chicken sat 25, 51, 72 weeks and overall mean ages of the bird. For this purpose thirty birds were selected from the flock of layers in the Babcock University Teaching and Research Farm. A total of thirty (30) eggs were collected daily from the birds continuously for five (5) days of egg production, at each age 25, 51 and 72 weeks. The total number of eggs collected at each age was 150 and 450 for the total of three age periods. Data were collected on egg production traits for egg length, egg breadth and egg shape index. The mean values of the egg quality traits revealed an apparent increase for egg length 4.05–4.65 cm and egg breadth 2.47–2.66 cm with a corresponding overall mean data 4.38 cm for egg length and 2.56 cm for egg breadth; however, egg shape index recorded decrease from 61.87 to 57.19 with a corresponding overall mean of 58.92. General linear model procedure of statistical analytical system was used to obtain the variance components for the estimation of heritability. High heritability estimates were obtained when the age variance was included in the computation for overall mean and at 25 weeks for the studied traits, and at 72 weeks for egg breadth and egg shape index when the age variance was excluded while low estimates were registered at 51 for all traits, and at 72 for egg length and with the corresponding overall mean for all traits when the age variance was excluded from the computation. The heritability estimates from different egg quality traits were low to high. Since some of the traits recorded low heritability values, these traits can be improved by mass selection thereby culminating into egg production with optimal quality. Keywords: Peak egg production, Age variance, Egg quality traits, Genetic potential, Heritabilit