Journal of Renewable Energy and Environment

Journal of Renewable Energy and Environment

Performance Characteristics of Photovoltaic Modules at Optimal Tilt Angle with Varying Shading Conditions: Embu County, Kenya Case Study

Document Type : Research Article

Authors
Martin Ntoruru
Millien Kawira
Ali Halake
Jackson Wachira
Department of Physical Sciences, School of Pure and Applied Sciences, University of Embu, P. O. Box: 6-60100, Embu, Kenya.
10.30501/jree.2026.512862.2309
Abstract
Photovoltaic (PV) modules are widely used technologies for converting solar radiation directly into electrical energy. This study investigated the performance characteristics of PV modules under varying shading conditions and tilt angles. The optimal tilt angle for Embu County was determined by adjusting the tilt of photovoltaic modules at different angles. Five PV modules (M_1, M_2, M_3, M_4 M_5) with identical specifications were installed on the rooftop of a selected building at the University of Embu and inclined at 0°, 5°, 10°, 15°, and 20°, respectively, all oriented along the south-north axis. Each module was connected to two multimeters to record variations in current and voltage. The modules were cleaned weekly, and the accumulated dust and particles were weighed using a beam balance. The average monthly accumulation of dust and particles was subsequently computed. To reduce costs and minimize risks associated with adjustments, a tilt angle of 10° is recommended for fixed PV modules, as this angle represents the optimal tilt for eight out of twelve months, accounting for 66.67% of the year. The effect of shading on the performance of PV modules inclined at 10° and 15° under different shading conditions was also examined. The results indicated that shading significantly reduces the output of the PV modules, with shading levels of 25% and 100% corresponding to a 36%–95% reduction in performance at both tilt angles. Shading did not affect the determination of the optimum tilt angle but primarily influenced the performance of the PV modules.

Graphical Abstract

Performance Characteristics of Photovoltaic Modules at Optimal Tilt Angle with Varying Shading Conditions: Embu County, Kenya Case Study
Keywords
Photovoltaic
Tilt
Optimal Angle
Shading Conditions
Energy

Subjects

1.        Ale, T. O., Rotipin, K., & Makanju, T. D. (2022). Temperature Effects on Optimal Performance of PV Module. Journal of Engineering Advancements, 162–165. https://doi.org/10.38032/jea.2022.04.004
2.        Alkaff, S. A., Shamdasania, N. H., Ii, G. Y., & Venkiteswaran, V. K. (2019). A Study on Implementation of PV Tracking for Sites Proximate and Away from the Equator. Process Integration and Optimization for Sustainability, 3(3), 375–382. https://doi.org/10.1007/s41660-019-00086-7
3.        Alshareef, M. J. (2023). A Comprehensive Review of the Soiling Effects on PV Module Performance. IEEE Access, 11, 134623–134651. https://doi.org/10.1109/ACCESS.2023.3337204
4.        Alzahrani, M., Rahman, T., Rawa, M., & Weddell, A. (2025). Impact of dust and tilt angle on the photovoltaic performance in a desert environment. Solar Energy, 288, 113239. https://doi.org/10.1016/j.solener.2025.113239
5.        Appelbaum, J. (2019). Shading and masking affect the performance of photovoltaic systems—A review. AIMS Energy, 7(1), 77–87. https://doi.org/10.3934/ENERGY.2019.1.77
6.        Brecl, K., Bokalič, M., & Topič, M. (2021). Annual energy losses due to partial shading in PV modules with cut wafer-based Si solar cells. Renewable Energy, 168, 195–203. https://doi.org/10.1016/j.renene.2020.12.059
7.        De Silva, R., & Fernando, S. (2022). Effect of Temperature on Solar cell performance in a Sri Lankan context. https://doi.org/10.14293/S2199-1006.1.SOR-.PPOSK8U.v1
8.        Dhimish, M., & Silvestre, S. (2019). Estimating the impact of azimuth-angle variations on photovoltaic annual energy production. Clean Energy, 3(1), 47–58. https://doi.org/10.1093/ce/zky022
9.        Handoko Rusiana, I., Yuda Bakti, Z., & Sambasri, S. (2018). Study and Analysis of Shading Effects on Photovoltaic Application System. MATEC Web of Conferences, 218, 02004. https://doi.org/10.1051/matecconf/201821802004
10.      Hua, L.-G., Memon, Q. A., Shaikh, M. F., Shaikh, S. A., Rahimoon, R. A., Shah, S. H. H., & Qadir, A. (2022). Comparative Analysis of Power Output, Fill Factor, and Efficiency at Fixed and Variable Tilt Angles for Polycrystalline and Monocrystalline Photovoltaic Panels—The Case of Sukkur IBA University. Energies, 15(11), 3917. https://doi.org/10.3390/en15113917
11.      Husin, K. A. K., Adenam, N. M., Mat Yunin, M. Y. A., Wong, K. N. S. W. S., Hashim, S. Z. M., & Adli, H. K. (2021). Monitoring and Optimizing Solar Power Generation of Flat-Fixed and Auto-Tracking Solar Panels with IoT System. IOP Conference Series: Materials Science and Engineering, 1062(1), 012011. https://doi.org/10.1088/1757-899X/1062/1/012011
12.      Kapoor, S., Sharma, A. K., & Porwal, D. (2021). Design and simulation of 60kWp solar on-grid system for rural area in Uttar-Pradesh by “PVsyst.” Journal of Physics: Conference Series, 2070(1), 012147. https://doi.org/10.1088/1742-6596/2070/1/012147
13.      Kumar, N. M., & Dinniyah, F. S. (2019). Influence of tilt angle on energy yields and performance ratios of grid connected photovoltaic generators in Southeast Asia. Progress in Industrial Ecology, An International Journal, 13(3), 264. https://doi.org/10.1504/pie.2019.10022059
14.      Kumar, N. S., Barik, D., Tudu, K., Praveenkumar, S., Dennison, M. S., & Ibrahim, T. K. (2025). Thermodynamic study of improved cooling in solar photovoltaic cells using nanofluids with graphite-doped titanium dioxide and aluminum oxide. Case Studies in Thermal Engineering, 69, 105969. https://doi.org/10.1016/j.csite.2025.105969
15.      Lin, G., Bimenyimana, S., Tseng, M.-L., Wang, C.-H., Liu, Y., & Li, L. (2020). Photovoltaic Modules Selection from Shading Effects on Different Materials. Symmetry, 12(12), 2082. https://doi.org/10.3390/sym12122082
16.      Mamun, M. A. A., Islam, M. M., Hasanuzzaman, M., & Selvaraj, J. (2021). Effect of tilt angle on the performance and electrical parameters of a PV module: Comparative indoor and outdoor experimental investigation. Energy and Built Environment, S2666123321000179. https://doi.org/10.1016/j.enbenv.2021.02.001
17.      Manzoor, H. U., Aaqib, S. M., Manzoor, T., Azeem, F., Ashraf, M. W., & Manzoor, S. (2025). Effect of Optimized Tilt Angle of PV Modules on Solar Irradiance for Residential and Commercial Buildings in Different Cities of Pakistan: Simulation‐Based Study. Energy Science & Engineering, 13(4), 1831–1845. https://doi.org/10.1002/ese3.70004
18.      Mehdipour, C., & Mohammadi, F. (2019). Design and Analysis of a Stand-Alone Photovoltaic System for Footbridge Lighting. Journal of Solar Energy Research, 4(2). https://doi.org/10.22059/jser.2019.283926.1120
19.      Niazi, K. A. K., Yang, Y., Nasir, M., & Sera, D. (2019). Evaluation of Interconnection Configuration Schemes for PV Modules with Switched-Inductor Converters under Partial Shading Conditions. Energies, 12(14), 2802. https://doi.org/10.3390/en12142802
20.      Noa, A. P., Perez, A. V., Hechavarria, J. M., & Santos, R. D. (2018). Energy interpretation of solar radiation affects for Artemisa province. International Journal of Physical Sciences and Engineering, 2(2), 39–49. https://doi.org/10.29332/ijpse.v2n2.142.
21.      Qiu, G., & Riffat, S. B. (2003). Optimum tilt angle of solar collectors and its impact on performance. International Journal of Ambient Energy, 24(1), 13–20. https://doi.org/10.1080/01430750.2003.9674898
22.      Samuel, N. N. (2021). Effects of land fragmentation on farm efficiency in three agro-ecological zones of Embu County in Kenya. African Journal of Agricultural Research, 17(2), 283–291. https://doi.org/10.5897/ajar2020.14902
23.      Sugirianta, I. B. K., Sunaya, I. G. A. M., & D Saputra, I. G. N. A. (2020). Optimization of tilt angle on-grid 300Wp PV plant model at Bukit Jimbaran Bali. Journal of Physics: Conference Series, 1450(1), 012135. https://doi.org/10.1088/1742-6596/1450/1/012135
24.      Yassir, A. (2019). Genetic Algorithm as a Solutions Optimization of Tilt Angles for Monthly Periods of Photovoltaic Installation. IOP Conference Series: Materials Science and Engineering, 536(1), 012100. https://doi.org/10.1088/1757-899X/536/1/012100
25.      Zhou, L., & Yang, L. (2018). Optimization of installing angles of photovoltaic panels to maximize solar radiation by simulated annealing algorithm. IOP Conference Series: Materials Science and Engineering, 452(3), 032004. https://doi.org/10.1088/1757-899X/452/3/032004
1.        Ale, T. O., Rotipin, K., & Makanju, T. D. (2022). Temperature Effects on Optimal Performance of PV Module. Journal of Engineering Advancements, 162–165. https://doi.org/10.38032/jea.2022.04.004
2.        Alkaff, S. A., Shamdasania, N. H., Ii, G. Y., & Venkiteswaran, V. K. (2019). A Study on Implementation of PV Tracking for Sites Proximate and Away from the Equator. Process Integration and Optimization for Sustainability, 3(3), 375–382. https://doi.org/10.1007/s41660-019-00086-7
3.        Alshareef, M. J. (2023). A Comprehensive Review of the Soiling Effects on PV Module Performance. IEEE Access, 11, 134623–134651. https://doi.org/10.1109/ACCESS.2023.3337204
4.        Alzahrani, M., Rahman, T., Rawa, M., & Weddell, A. (2025). Impact of dust and tilt angle on the photovoltaic performance in a desert environment. Solar Energy, 288, 113239. https://doi.org/10.1016/j.solener.2025.113239
5.        Appelbaum, J. (2019). Shading and masking affect the performance of photovoltaic systems—A review. AIMS Energy, 7(1), 77–87. https://doi.org/10.3934/ENERGY.2019.1.77
6.        Brecl, K., Bokalič, M., & Topič, M. (2021). Annual energy losses due to partial shading in PV modules with cut wafer-based Si solar cells. Renewable Energy, 168, 195–203. https://doi.org/10.1016/j.renene.2020.12.059
7.        De Silva, R., & Fernando, S. (2022). Effect of Temperature on Solar cell performance in a Sri Lankan context. https://doi.org/10.14293/S2199-1006.1.SOR-.PPOSK8U.v1
8.        Dhimish, M., & Silvestre, S. (2019). Estimating the impact of azimuth-angle variations on photovoltaic annual energy production. Clean Energy, 3(1), 47–58. https://doi.org/10.1093/ce/zky022
9.        Handoko Rusiana, I., Yuda Bakti, Z., & Sambasri, S. (2018). Study and Analysis of Shading Effects on Photovoltaic Application System. MATEC Web of Conferences, 218, 02004. https://doi.org/10.1051/matecconf/201821802004
10.      Hua, L.-G., Memon, Q. A., Shaikh, M. F., Shaikh, S. A., Rahimoon, R. A., Shah, S. H. H., & Qadir, A. (2022). Comparative Analysis of Power Output, Fill Factor, and Efficiency at Fixed and Variable Tilt Angles for Polycrystalline and Monocrystalline Photovoltaic Panels—The Case of Sukkur IBA University. Energies, 15(11), 3917. https://doi.org/10.3390/en15113917
11.      Husin, K. A. K., Adenam, N. M., Mat Yunin, M. Y. A., Wong, K. N. S. W. S., Hashim, S. Z. M., & Adli, H. K. (2021). Monitoring and Optimizing Solar Power Generation of Flat-Fixed and Auto-Tracking Solar Panels with IoT System. IOP Conference Series: Materials Science and Engineering, 1062(1), 012011. https://doi.org/10.1088/1757-899X/1062/1/012011
12.      Kapoor, S., Sharma, A. K., & Porwal, D. (2021). Design and simulation of 60kWp solar on-grid system for rural area in Uttar-Pradesh by “PVsyst.” Journal of Physics: Conference Series, 2070(1), 012147. https://doi.org/10.1088/1742-6596/2070/1/012147
13.      Kumar, N. M., & Dinniyah, F. S. (2019). Influence of tilt angle on energy yields and performance ratios of grid connected photovoltaic generators in Southeast Asia. Progress in Industrial Ecology, An International Journal, 13(3), 264. https://doi.org/10.1504/pie.2019.10022059
14.      Kumar, N. S., Barik, D., Tudu, K., Praveenkumar, S., Dennison, M. S., & Ibrahim, T. K. (2025). Thermodynamic study of improved cooling in solar photovoltaic cells using nanofluids with graphite-doped titanium dioxide and aluminum oxide. Case Studies in Thermal Engineering, 69, 105969. https://doi.org/10.1016/j.csite.2025.105969
15.      Lin, G., Bimenyimana, S., Tseng, M.-L., Wang, C.-H., Liu, Y., & Li, L. (2020). Photovoltaic Modules Selection from Shading Effects on Different Materials. Symmetry, 12(12), 2082. https://doi.org/10.3390/sym12122082
16.      Mamun, M. A. A., Islam, M. M., Hasanuzzaman, M., & Selvaraj, J. (2021). Effect of tilt angle on the performance and electrical parameters of a PV module: Comparative indoor and outdoor experimental investigation. Energy and Built Environment, S2666123321000179. https://doi.org/10.1016/j.enbenv.2021.02.001
17.      Manzoor, H. U., Aaqib, S. M., Manzoor, T., Azeem, F., Ashraf, M. W., & Manzoor, S. (2025). Effect of Optimized Tilt Angle of PV Modules on Solar Irradiance for Residential and Commercial Buildings in Different Cities of Pakistan: Simulation‐Based Study. Energy Science & Engineering, 13(4), 1831–1845. https://doi.org/10.1002/ese3.70004
18.      Mehdipour, C., & Mohammadi, F. (2019). Design and Analysis of a Stand-Alone Photovoltaic System for Footbridge Lighting. Journal of Solar Energy Research, 4(2). https://doi.org/10.22059/jser.2019.283926.1120
19.      Niazi, K. A. K., Yang, Y., Nasir, M., & Sera, D. (2019). Evaluation of Interconnection Configuration Schemes for PV Modules with Switched-Inductor Converters under Partial Shading Conditions. Energies, 12(14), 2802. https://doi.org/10.3390/en12142802
20.      Noa, A. P., Perez, A. V., Hechavarria, J. M., & Santos, R. D. (2018). Energy interpretation of solar radiation affects for Artemisa province. International Journal of Physical Sciences and Engineering, 2(2), 39–49. https://doi.org/10.29332/ijpse.v2n2.142.
21.      Qiu, G., & Riffat, S. B. (2003). Optimum tilt angle of solar collectors and its impact on performance. International Journal of Ambient Energy, 24(1), 13–20. https://doi.org/10.1080/01430750.2003.9674898
22.      Samuel, N. N. (2021). Effects of land fragmentation on farm efficiency in three agro-ecological zones of Embu County in Kenya. African Journal of Agricultural Research, 17(2), 283–291. https://doi.org/10.5897/ajar2020.14902
23.      Sugirianta, I. B. K., Sunaya, I. G. A. M., & D Saputra, I. G. N. A. (2020). Optimization of tilt angle on-grid 300Wp PV plant model at Bukit Jimbaran Bali. Journal of Physics: Conference Series, 1450(1), 012135. https://doi.org/10.1088/1742-6596/1450/1/012135
24.      Yassir, A. (2019). Genetic Algorithm as a Solutions Optimization of Tilt Angles for Monthly Periods of Photovoltaic Installation. IOP Conference Series: Materials Science and Engineering, 536(1), 012100. https://doi.org/10.1088/1757-899X/536/1/012100
25.      Zhou, L., & Yang, L. (2018). Optimization of installing angles of photovoltaic panels to maximize solar radiation by simulated annealing algorithm. IOP Conference Series: Materials Science and Engineering, 452(3), 032004. https://doi.org/10.1088/1757-899X/452/3/032004

  • Receive Date 17 March 2025
  • Revise Date 22 November 2025
  • Accept Date 30 December 2025