Long-Term Durability of Rooftop Grid-Connected Solar Photovoltaic Systems

Compared to their initial performance, solar photovoltaic (PV) arrays show long-term performance degradation, resulting in lower like-for-like efficiencies and performance ratios. The long-term durability of polycrystalline silicon (p-Si) solar PV modules in three roof-top grid-connected arrays has been examined. Electrical output, ambient temperature, cell temperature, solar irradiance, solar irradiation, and wind speed data were collected at hourly intervals from 2017 to 2021 from three 50 kWp PV installations in Northern Ireland. The results show the extent to which higher PV temperatures associated with more intense solar radiation decrease efficiency, fill factor and maximum power output for PV arrays in a temperate climate. Long-term durability trends for grid-connected roof-top solar photovoltaic systems can be obscured by diurnal and seasonal changes in environmental conditions. To reduce the influence of variable conditions, performance ratios (PRcorr) were “corrected” using the measured annual average cell temperature (Tcell_avg). Introduction of this temperature-correction reduced the seasonal variation of the performance ratio. Using temperature-corrected performance ratios, long-term (in this case those seen after fiveyears operation) performance degradation trends become evident with high confidence after six months for one PV array and within three years for the two other arrays. If lower statistical confidence in trends is acceptable, long-term degradation rates can be identified within one year of operation for all PV arrays examined. These results have the important implication that relatively short-duration outdoor PV performance monitoring may be reliably used to estimate long-term degradation and/or to calibrate normally-conducted accelerated testing

Long-Term Durability of Solar Photovoltaic Modules

Solar photovoltaic (PV) panels experience long-term performance degradation resulting in lower like-per-like efficiencies and performance ratios when compared with their initial performance. Manufacturers of solar photovoltaic modules usually guarantee the life span for more than 20 years. It is therefore necessary to track and mitigate degradation of PV modules over this period to satisfy such guarantees and beyond this period to identify maintenance and repair requirements. Degradation of solar PV modules makes them less efficient, less reliable and, ultimately, inoperative. This paper reviews relevant literature to discuss: Causes of efficiency reductions in photovoltaic cells Ways to achieve long-term durability of solar photovoltaic modules How viability of solar photovoltaic modules is affected by degradation The remedies to solar photovoltaic (PV) degradatio

Comparison of Predicted and Measured Annual Performance of a Roof-Top Grid-Connected PV System in the Irish Climate

The problem of energy scarcity has reached a global scale as a result of the majority of energy production relying on non-renewable sources of energy. Solar photovoltaic cells use the photovoltaic effect to convert solar energy into electrical energy. Solar energy can reduce emissions of carbon dioxide (CO2) associated with the generation from fossil fuels as the only CO2 emissions are those embodied in their manufacture. A 268.8 m2 area roof-top grid-connected PV system with a total capacity of 49.92kWp was installed at Warrenpoint (54.11oN and 6.26oW) in Ireland. 192 “Renesola” PV modules were installed with a nominal peak output of 260Wp and efficiency at standard test conditions (STC) of 18.5%. System outputs were measured at 15-minute intervals over a year. A system simulation was carried out to predict average annual energy yield, average system efficiency, and average system performance ratio. The system simulation showed that an annual average energy yield of 12,695.2 MJ (3,526.4 kWh) was generated at an average system performance ratio of 85% and average system efficiency of 15.8%. System measurements showed an average annual energy yield of 12,035.8 MJ (3,343.5 kWh) at an average system performance ratio of 85.17% and system efficiency of 15.82%. The system performance ratio measured was greater than the performance ratio predicted by system simulation by 0.17%. The system’s measured efficiency was greater than that given by the system simulation by 0.02%. The average annual energy yield (12,695.2 MJ) predicted by the simulation was greater than the system’s measured annual energy yield (12,035.8 MJ) by 659.4 MJ

THE EFFECTS OF THE TRANSIENT AND PERFORMANCE LOSS RATES ON PV OUTPUT PERFORMANCE

Solar photovoltaic (PV) panels experience long-term performance degradation as compared to their initial performance, resulting in lower like-per-like efficiencies and performance ratios. Manufacturers of solar photovoltaic modules normally guarantee a lifespan of more than 20 years. To meet such commitments, it is important to monitor and mitigate PV module degradation during this period, as well as beyond, to recognize maintenance and repair needs. Solar PV modules degrade over time, becoming less effective, less reliable, and eventually unusable. The effects of transient and performance loss rates on the output performance of polycrystalline silicon (p-Si) solar PV modules are the focus of this study. PV modules\u27 electrical performance and solar energy conversion efficiency change as solar irradiance and ambient temperature change. A rise in ambient temperature or a decrease in solar irradiance, for example, all result in a reduction in performance. Large variations in operating conditions due to uncontrollable external parameters such as cloud movement and wind velocity, as well as changes in factors external to PV systems such as unexpected shading, inverter problems, and control failures, may trigger transient performance changes on PV modules output. The data used in this analysis were from the Warrenpoint site location of the Electric Supply Board (ESB) for the years 2016-2020. Clear days in winter, spring, summer, and autumn were caused by a rise in daily sunshine hours in February, May, June, and September, according to the output performance. Due to the highest amount of solar irradiation at the site location, these days saw an increase in PV output generation. According to the performance loss rates, the median degradation rates in 2016 (4.5%/year to 14%/year) and 2017 (0.1%/year to 5.2%/year) are 8.40%/year and 3.87%/year, respectively. This means that the degradation rate is greater than 1%/year, the hazardous probability is between 90% and 100%, and severity of 10 is given (With an associated failure of corrosion in solder bonds). 2018 (-7.5%/year to 2.5%/year), 2019 (-16%/year to -23%/year), and 2020 (-5.1%/year to -10% /year) had median degradation rates of -2.75%/year, -18.23%/year, and -5.2%/year, respectively. This shows that the degradation rates are less than 1% per year, and their hazardous probabilities range from severity rank 9 to 1, or 80% to 70% to 0% safety risk. All of these factors have a negative impact on PV output performance

Reviewing the External Factors that Influence PV Output Performance in the Irish Climate

The literature review presented in this paper centres on the external factors that influence PV output performance in the Irish climate. Solar photovoltaic (PV) panels show long-term performance degradation, resulting in lower like-per-like efficiencies and performance ratios. Manufacturers of solar photovoltaic modules typically guarantee a life span of more than 20 years. But to meet such guarantees, it is necessary to track and mitigate PV module degradation during this period, and identify maintenance and repair requirements beyond this period. Solar PV modules degrade over time, becoming less efficient, less reliable, and, eventually, inoperable. External factors such as solar irradiance, dust deposition, shading, ambient temperature, operating cell temperature, humidity and wind velocity affect the PV output performance in the Irish climate. This is because the performance of a PV system is heavily influenced by the meteorological conditions of the site locations. Therefore, this paper reviews the external factors that influence PV output performance in the Irish climate

Influence of Site and System Parameters on the Performance of Roof-Top Grid-Connected PV Systems Installed in Harlequins, Belfast, Northern Ireland

The problem of energy scarcity has hit a global scale because of the dependency of most of the energy generation on non-renewable sources (e.g., fossil fuels). As in supply and demand laws, the lower the amount of energy provided, the more expensive it becomes, causing a major problem for the industry in general, which is dependent on it. These non-renewable energy sources contribute to environmental degradation effects and depletion of the ozone layer from the atmosphere. To reduce this effect, the use of renewable energy sources which is environmentally friendly has been on the growing index across the globe. Solar photovoltaic cells transform solar energy into electrical energy through the photovoltaic effect. Solar energy can minimise the carbon dioxide (CO2) emissions associated with the generation of electricity from fossil fuels since the only CO2 emissions associated with the generation of fossil fuels are those in their production. Solar PV electricity is more environmentally friendly since it is carbon-free at the point of generation compared to fossil fuel generation. In this paper, we examine the various site and system parameters that influence the performance of the 49.92 kWp roof-top grid-connected PV system installed at Harlequins, Belfast, Northern Ireland using a five-year dataset (from 2017-2021). The site parameters examined are ambient temperature, relative humidity, irradiation, wind speed and air pressure while the system parameters examined are inverter efficiency, system performance ratio, system efficiency, fill factor, DC array and AC final yields, DC array capture loss, AC system loss and normalised output power efficiency. The result of our analysis shows that an increase in ambient temperature, solar cell temperature, relative humidity and solar irradiation decreases the PV system performance output while an increase in wind speed reduces both ambient and solar cell temperatures but increases dust accumulation on the surface of the solar panel. An increase in air pressure increases the solar irradiation and AC power output generations

Effect of Transient Performance Changes on Photovoltaic Modules Output

The electrical output and solar energy conversion efficiency of PV modules varies with solar irradiance and ambient temperature. For instance, an increase in ambient temperature or a decrease in solar irradiance both lead to a reduction in output. Transient performance changes on PV modules output may be caused as a result of large fluctuations of the operational conditions due to uncontrollable external parameters such as rain, cloud movement and wind velocity together with changes of factors external to PV systems such as unexpected shading, inverter problems and control failures. The data used in this study is a daily detailed data set (from July 01-15, 2018) from the installed roof-top solar photovoltaic (PV) array at Dublin Energy Lab (DEL), Grangegorman, Ireland. These data were analysed to find the effect of transient performance changes and PV output generation. The effect of transient performance changes were verified from the distorted peaks of day 1 to 5 of the PV output generation. PV performance variations were analysed in a clustered column plot of hourly efficiency, bubble plots showing an increase in hourly efficiency with respect to hourly solar radiation, a decrease in hourly performance ratio with respect to hourly solar radiation, a decrease in hourly global performance ratio with respect to hourly global solar radiation and an increase in hourly solar radiation with respect to hourly global solar radiation. Finally, the effect of daily transient performance changes were unveiled through graphical plots