Photovoltaic Soiling Characterisation and Performance Mapping in Nigeria

Abstract In Nigeria, the rapid population increase and the overreliance on fossil fuel have created significant environmental, health, political and economic consequences leading to severe socio-economic drawbacks. These factors have developed a wide gap between energy demand and supply due to insufficient local production, necessitating the need for a clean energy supply for all. The photovoltaic device's economic and environmental merits have made it the most suitable clean energy alternative to help developing countries such as Nigeria achieve the SDG-7. However, apart from the device's low efficiency, which is undergoing intensive study across the globe, another omnipresent factor is surface soiling, which is grossly underestimated and has a deleterious impact on a solar cell's performance. The accumulation of dust on photovoltaic (PV) devices adversely impacts their performance and is grossly underestimated. It is location-dependent and influenced by a number of factors, which raises concern for the potential investor, policymakers, engineers, and local populace in regions where the soiling rate and potential threats remain relatively unexplored. Energy losses from PV due to dust is an issue that cannot be ignored and can be an obstacle to achieving renewable energy targets in Nigeria. In this context, this thesis presents several mitigation techniques available to maintain a certain level of performance. This research begins with a systematic review of related literature on the country's energy crisis and renewable energy potential, leading to an overview of solar energy potential and penetration in the country, resulting in a comprehensive literature review on the effect of dust on PV performance. Several studies investigating factors influencing dust accumulation were conducted: First, indoor research investigated soiling on photovoltaic modules, focusing on dust properties and PV surface materials as influencing factors. Solar simulators, the spectrometer and SEM/EDX, were used to characterise the effect of accumulation of 13 different samples (ash, bird droppings, carpet dust, cement, charcoal, clay, coarse sand, laterite, loam soil, salt, sandy soil, stone dust and wood dust) on PV performance. Besides, the same experiment examines the performance of two leading PV covering materials (low iron glass and acrylic plastic). Outdoor studies investigated the influence of angular dependencies and optical losses in Abuja and across the country's six geopolitical zones by employing a low-cost coupon holder to expose low iron glass (50 mm x 50 mm) considering time stamp (annual, seasonal, and monthly variation). Soiled coupons were subjected to optical characterisation using a spectrometer and imaging analysis by employing SEM/EDX. Four PV modules (Monocrystalline Silicon, Polycrystalline Silicon, Cadmium Telluride and amorphous Silicon) were exposed in the Northern region to investigate PV yield reduction and correlate with yield measured under standard conditions. Low iron coupons were also exposed at the same period to determine the optical losses using a spectrometer and minerals morphology employing SEM/EDX. Finally, a correlation in-situ study to examine five cost-effective PV soiling mitigation techniques was conducted to determine the most effective and suitable approach by employing two types of PV surface covering materials (low iron glass and acrylic plastic) considering seasonal variation. The findings confirm that the country is blessed with enormous solar energy potential. However, its penetration is low, and the majority of the population is suffering from energy starvation. Findings from the review highlight dust accumulation on PV as one of the main obstacles preventing solar energy penetration. The indoor study findings reveal alarming losses showing that charcoal has the worst degradation effect on PV performance with approximately 98% reduction in short circuit current, while salt seems to have the most negligible impact with about 7%. It shows that acrylic plastic accumulates more dust than low iron glass and wet deposition promotes more adhesion on coupons than dry deposition. The outdoor studies' results revealed that the highest reduction in transmittance was recorded on a horizontally positioned coupon with a significant decrease of about 88% and lowest on a vertically positioned coupon with a reduction in the region of 1%. Similarly, the most significant mass of 12.56 g/m2 was recorded on a horizontally exposed coupon. It is observed that higher losses were recorded on a coupon positioned in the horizontal plane. Optical losses findings were used to develop soiling, which was correlated with another map revealing a significant variation. The PV performance experiment results reveal a significant decrease of ISC on all the modules with 73% on a-Si and the lowest of about 65% Si. It shows a yield loss of 78.3% for a-Si, 77% for CdTe, 70% for pc-Si, and 68.6% for the mc-Si module. Efficiencies decline of 78% for a-Si, 77% for CdTe, 71% for pc-Si and 71% for mc-Si. The optical loss results validated the output performance losses with a similar trend. The cleaning technique experimental findings show that the self-cleaning approach provides high preventive and restorative performance during the wet season, with about 99% on a low iron glass. Both manual cleanings with squeegee/water and self-cleaning demonstrated a 95% performance during the dry season on a low iron glass coupon. The least effective performance was recorded on the natural cleaning during the dry season with about 28% reduction in a month. The ramifications caused by soiling cannot be overlooked or overemphasised; thus, it is recommended to deploy PV modules in outdoor conditions and further examine each soiling mitigation technique's effectiveness and cost analysis over a longer duration in different regions

An analytical indoor experimental study on the effect of soiling on PV, focusing on dust properties and PV surface material

Photovoltaic technology penetration is experiencing noticeable progress. However, its performance is significantly affected by soiling, which is influenced by several factors such as site characteristics, weather, tilt angle and surface orientation, surface material and dust properties. This indoor study investigates the effect of soiling on photovoltaic modules, focusing on dust properties and PV surface materials as influencing factors. A Solar simulator, spectrometer and SEM/ EDX were used to characterise and investigate the effect of accumulation of 13 different samples (ash, bird droppings, carpet dust, cement, charcoal, clay, coarse sand, laterite, loam soil, salt, sandy soil, stone dust and wood dust) on PV performance. The findings develop upon previous studies on the effects of dust particle accumulation on PV performance by using more dust samples and applying more rigorous techniques. The results show that charcoal appears to have the worst degradation effect on PV performance with about 98% reduction in short circuit current while salt seems to have the least impact with about 7%. The influence of 2 PV surface materials (acrylic plastic and low iron glass) on dust accumulation were examined, and results show that the acrylic plastic accumulates more dust when compared to low iron glass. Results also show that dry deposition has a reduced adhesion to the coupons compared to wet deposition. The findings could be used in selecting PV farm sites by avoiding areas with high pollution, and it could stimulate further research on selecting an appropriate mitigation technique. The ramifications caused because of soiling cannot be overlooked or overemphasis; as such there is a need to identify appropriate and cost-effective mitigation techniques that can continue to promote the global penetration of PV technologies and sustain its performance

Dust and PV Performance in Nigeria: A review

The accumulation of dust on photovoltaic (PV) devices has an adverse impact by degrading their performance. In this work, a review of the effects of dust accumulation on PV module performance and measures to mitigate them have been provided. Energy losses from PV due to dust is an issue which cannot be ignored and can be an obstacle to achieving renewable energy targets in Nigeria. However, this paper presents a number of mitigation techniques which are available to maintain a certain level of performance. There is a need for further conduct comprehensive research on the effects of dust in all geopolitical regions in Nigeria to acquire data that can be used for designing the PV module system considering the most suitable technique in reducing or preventing the effects of soiling in each specific area

Nigeria's energy review: Focusing on solar energy potential and penetration

In Nigeria, the rapid population increase and the overreliance on fossil fuel have created significant environmental, health, political, and economic consequences leading to severe socio-economic drawbacks. These factors have developed a wide gap between energy demand and supply due to insufficient local production, necessitating a clean energy supply for all. The photovoltaic device's economic and environmental merits have made it the most suitable clean energy alternative to help developing countries such as Nigeria achieve the SDG-7. However, apart from the device's low efficiency, which is undergoing intensive study globally, other factors affect the penetration of the technology in developing countries, particularly Nigeria. This report systematically reviews the literature on the country's energy crisis and renewable energy potential, leading to an overview of solar energy potential and penetration. The potential of the technology and its penetration in the country were provided. A list highlighting challenges hindering technology penetration was also provided, and a solution for each was recommended

Soiling on PV performance influenced by weather parameters in Northern Nigeria

The photovoltaic device's economic and environmental merits have made it the most suitable clean energy alternative to help developing countries achieve the SDG-7. However, the low efficiency of the device, which is undergoing massive study across the globe, there is another omnipresent factor, such as surface soiling that has a deleterious effect on a solar cell's performance, which is influenced by wind speed/direction, humidity and temperature. This study investigates the impact of dust on four PV types (Monocrystalline Silicon, Polycrystalline Silicon, Cadmium Telluride and amorphous Silicon) in a city with two large commissioned and one massive solar farm under construction considering wind, humidity, rain, temperature and dust particles under extreme conditions. Low iron glass coupons were also exposed in seasonal, monthly, and annual categories to determine optical losses, soiling rates, and deposition mass. Accumulated dust particles on the surface of the coupon were subjected to SEM/EDX imaging to identify the deposited minerals' morphology. The findings reveal a massive performance decline due to soiling on all exposed modules with a most significant ISC decrease recorded about 73% on a-Si and least about 65% of the Si modules in one year without cleaning and a total of seventeen months exposure. The outcome shows significant losses recorded, where a yield loss of 78.3% and efficiencies decline of 78% for amorphous Si, 77% and 77% for cadmium telluride, 70% and 71% for polycrystalline and 68.6% and 71% for the monocrystalline Si module. A wide variation of performance losses was recorded between months and seasons in 2021, and the dry season presented the most alarming rates. The optical loss results validated the above output performance losses with a similar trend. The particle characterisation reveals that mineral particles > PM10 size with opaque and translucent morphology were the main constituent of dust formation on the examined coupons. It is recommended to study various mitigation techniques and use the correct one in an optimal cycle, which is cost-effective, which could restore and maintain the installation's optimal efficiency

Knowledge, Attitudes and Practices on Exclusive Breastfeeding in Adamawa, Nigeria

Abstract Background: Despite the efficacy of the Early Exclusive Breastfeeding (EBF) approach to child nutrition in reducing child mortality, few nursing mothers in Nigeria are willing to adopt this method of feeding. Objective: This research was therefore undertaken in order to assess the Knowledge, Attitudes and Practices (KAP) on EBF of antenatal clinic attendees in North-eastern Nigeria. Study Design: Cross Sectional Community Survey. Methods: Two hundred and fifty expectant mothers attending the ANC clinical sessions at Specialist Hospital, Yola, Adamawa State, were recruited for this study. The mean age of the women was twenty eight. Data was generated from a corpus consisting of health talks and questionnaires on the respondents' KAP on EBF during these clinical sessions at this health facility. Results: The results of the survey revealed the problems that inhibit or reduce the practice of exclusive breastfeeding to include the following: the assumption that colostrum is stale milk--84%; breast milk lacks sufficient nutrients--approximately 62%; and expressed breast milk is contaminated milk--just under 98%. With respect to the mother's attitude to EBF, 60% believed that this method of feeding would flatten their breasts and 78% that EBF causes respiratory tract infections. Furthermore, over 64% thought that food supplements were ideal for infants and that EBF was suitable only for working mothers. Conclusion: These results clearly demonstrate the lack of awareness and education on EBF. From both a national and international perspectives, poor maternal nutrition, inadequate support from spouses, family and even nurses and doctors are some of the constraints that limit the rate of practicing exclusive breastfeeding. Public health initiatives on the benefits of EBF need to be addressed, particularly at antenatal clinics and also through outreach programs that target mothers in the rural communities who have limited access to health care

Physicochemical and Amino acid Evaluation of Hura crepitans Seeds

Physico-chemical properties, amino acid profile, fatty acid and of Hura crepitans Seeds were evaluated. Fatty acid analysis revealed that palmitic acid (24.12%, stearic acid (16.86%), Oleic acid (56.08%), pentafluropropionic acid (0.87%) and non-fatty acid (2.07%). Hura crepitans seed indicate high level of unsaturated fatty acid mainly Oleic acid (56.08%). Physico-chemical analysis was carried out on soxhlet extracted oil (n-hexane) has the following properties: acid value (5.6±0.19 mgKOH/g), Saponification value (92.57±0.94 mgKOH/g). Iodine value (90.42±0.023gI2/100g). Free fatty acid (2.9±0.93 mgKOH/g), Calorific value (43,719.59±0.90 kJ/kg). Amino acid profile revealed the presence of 18 amino acids. Sulphur containing amino acids (Cysteine and methionine) are the most limiting amino acid for adult and children. While lysine and threonine are 2nd and 3rd limiting amino acid for children. The overall results indicate that if the seeds are properly utilized, they could be used as a Protein supplement, bio-fuel and could be used industrially for soap making

Angular dependencies of soiling loss on photovoltaic performance in Nigeria

Photovoltaic performance is significantly affected by soiling on its covering surface, which is strongly influenced by its tilt angle. This raises concern for the potential investor, policymakers, engineers, and local populace in regions where the soiling rate and its potential threats remain relatively unexplored. This study investigated the effect of dust accumulation on PV, considering the influence of tilt angle using a low-cost in-house developed soiling station exposed in a region with high solar energy potential, low PV penetration and high energy demand. Low iron glass coupons were exposed monthly, seasonally, and annually, each in three-position (horizontal, 45° tilt, and vertical plane). The result revealed that the highest reduction in transmittance was recorded on a horizontally positioned coupon with a significant decrease of about 88%. In comparison, the lowest transmittance reduction of an exposed coupon was recorded from a vertical position with about a 1% reduction. These transmittance reductions were further illustrated using PV power output reduction. Accumulated dust density on each coupon was recorded, with the lowest of about 0.2 g/m2 and the highest of 12.56 g/m2. It was concluded that horizontally positioned coupons accumulated more dust and gradually decreased as the angle tilted towards the vertical position. This research work highlights cycles of high soiling in the region; the information could be used to predict soiling events that could provide maintenance guidance where optimum scheduling for preventing and restoring PV performance can be achieved

Dust and PV Performance in Nigeria: A review

The accumulation of dust on photovoltaic (PV) devices has an adverse impact by degrading their performance. In this work, a review of the effects of dust accumulation on PV module performance and measures to mitigate them have been provided. Energy losses from PV due to dust is an issue which cannot be ignored and can be an obstacle to achieving renewable energy targets in Nigeria. However, this paper presents a number of mitigation techniques which are available to maintain a certain level of performance. There is a need for further conduct comprehensive research on the effects of dust in all geopolitical regions in Nigeria to acquire data that can be used for designing the PV module system considering the most suitable technique in reducing or preventing the effects of soiling in each specific area

Soiling on PV performance influenced by weather parameters in Northern Nigeria

The photovoltaic device's economic and environmental merits have made it the most suitable clean energy alternative to help developing countries achieve the SDG-7. However, the low efficiency of the device, which is undergoing massive study across the globe, there is another omnipresent factor, such as surface soiling that has a deleterious effect on a solar cell's performance, which is influenced by wind speed/direction, humidity and temperature. This study investigates the impact of dust on four PV types (Monocrystalline Silicon, Polycrystalline Silicon, Cadmium Telluride and amorphous Silicon) in a city with two large commissioned and one massive solar farm under construction considering wind, humidity, rain, temperature and dust particles under extreme conditions. Low iron glass coupons were also exposed in seasonal, monthly, and annual categories to determine optical losses, soiling rates, and deposition mass. Accumulated dust particles on the surface of the coupon were subjected to SEM/EDX imaging to identify the deposited minerals' morphology. The findings reveal a massive performance decline due to soiling on all exposed modules with a most significant ISC decrease recorded about 73% on a-Si and least about 65% of the Si modules in one year without cleaning and a total of seventeen months exposure. The outcome shows significant losses recorded, where a yield loss of 78.3% and efficiencies decline of 78% for amorphous Si, 77% and 77% for cadmium telluride, 70% and 71% for polycrystalline and 68.6% and 71% for the monocrystalline Si module. A wide variation of performance losses was recorded between months and seasons in 2021, and the dry season presented the most alarming rates. The optical loss results validated the above output performance losses with a similar trend. The particle characterisation reveals that mineral particles > PM10 size with opaque and translucent morphology were the main constituent of dust formation on the examined coupons. It is recommended to study various mitigation techniques and use the correct one in an optimal cycle, which is cost-effective, which could restore and maintain the installation's optimal efficiency