Disaggregating Longer-Term Trends from Seasonal Variations in Measured PV System Performance
Abstract
:1. Introduction
2. Solar PV Performance Monitoring
2.1. Seasonal Variations in PV Performance
2.2. Performance Ratio Corrected for Temperature (PRCorr)
3. Materials and Methods
4. Results
4.1. Data Collection and Preprocessing
4.2. Time Series
4.3. Wavelet Analysis
4.4. Performance Ratio
- di: difference between corrected and uncorrected PR (see Equation (6)).
- n: number of monitored data points.
- DF = n − 1: degree of freedom.
- TC.I: t-test at a particular confidence interval (C.I).
- S.E(dmean): standard error of the mean difference.
4.5. Statistical Analyses Using t-Distribution and Confidence Intervals
5. Discussion
6. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Appendix A
Harlequins | Observation | Newry | Observation | Warrenpoint | Observation | |||
---|---|---|---|---|---|---|---|---|
Arr. PLRrel (%/a) | Sys. PLRrel (%/a) | This means that PLRrel of the Harlequins array shows that solar panel generation will increase at the annual rate by −0.27%/a, which shows an improvement, while PLRrel of the Harlequins system shows that PV system generation will decrease at the annual rate of 0.018%/a. | Array PLRrel (%/a) | Sys. PLRrel (%/a) | There are improvements in both the Newry array and system. For this reason, both the PLRrel for the Newry array and system show that they will both increase at the annual rates by −0.23%/a and −0.00635%/a, respectively. | Arr. PLRrel (%/a) | Sys. PLRrel (%/a) | The PLRrel in Warrenpoint array shows that there is an improvement in the array. This means that solar panel generation will increase at an annual rate of −0.17%/a, while the PLRrel in the Warrenpoint system shows that PV system generation will decrease at the annual rate of 0.00514%/a. |
−0.27 | 0.018 | −0.23 | −0.00635 | −0.17 | 0.00514 |
Harlequins | Observation | Newry | Observation | Warrenpoint | Observation | |||
---|---|---|---|---|---|---|---|---|
Arr. PLRabs (/a) | Sys. PLRabs (/a) | The PLRabs of the Harlequins array show that solar panel generation will increase at the annual rate of −0.26/a, which shows an improvement, while the PLRabs of the Harlequins system shows that PV system generation will decrease at the annual rate of 0.017/a. | Arr. PLRabs (/a) | Sys. PLRabs (/a) | Both the Newry array and system show improvements. This means that their PLRabs will increase at the annual rates by −0.21/a and −0.006/a, respectively. | Arr. PLRabs (/a) | Sys. PLRabs (/a) | Warrenpoint array shows a PLRabs improvement while the Warrenpoint system shows a decrease in PLR abs. This shows that solar panel generation will increase at an annual rate of −0.16/a, while the Warrenpoint system shows that PV system generation will decrease at an annual rate of 0.0048/a. |
−0.26 | 0.017 | −0.21 | −0.006 | −0.16 | 0.0048 |
Harlequins | Observation | Newry | Observation | Warrenpoint | Observation | |||
---|---|---|---|---|---|---|---|---|
Arr. PLRrel (%/a) | Sys. PLRrel (%/a) | Both the Harlequins array and system showed an improvement at their PLRrel. This shows that solar panel and PV generations will increase at annual rates of −0.16%/a and −0.023%/a, respectively. It will be difficult to predict any PLRrel in the PV array and system due to the seasonal variation effect noticed in weather-uncorrected relative performance loss rates. To resolve this, the weather-uncorrected PLRrel are normalised with the average cell temperature. | Array PLRrel (%/a) | Sys. PLRrel (%/a) | There are improvements in the Newry array and system. For this reason, their PLRrel shows that both the Newry array and system will increase at the annual rates by −0.01%/a and −0.00104%/a, respectively. Just like the Harlequins array and system, it will be difficult to predict any PLRrel in the PV array and system due to the seasonal variation effect noticed in weather-uncorrected relative performance loss rates. To resolve this, the weather-uncorrected PLRrel are normalised with the average cell temperature. | Arr. PLRrel (%/a) | Sys. PLRrel (%/a) | There is an improvement in the Warrenpoint array and a decrease in the Warrenpoint system. This shows that solar panel generation will increase at an annual rate by −0.063%/a, while the Warrenpoint system shows that PV system generation will decrease at the annual rate of 0.00259%/a. |
−0.16 | −0.023 | −0.01 | −0.00104 | −0.063 | 0.00259 |
Harlequins | Observation | Newry | Observation | Warrenpoint | Observation | |||
---|---|---|---|---|---|---|---|---|
Arr. PLRabs (/a) | Sys. PLRabs (/a) | Both the Harlequins array and system show improvements in PLRabs. This show that solar panel and PV generations will increase at annual rates of −0.15/a and −0.022/a. Just like PLRrel in the Harlequins array and system, it will be difficult to predict any PLRrel in the PV array and system due to the seasonal variation effect noticed in weather-uncorrected relative performance loss rates. To resolve this, the weather-uncorrected PLRrel are normalised with the average cell temperature. | Arr. PLRabs (/a) | Sys. PLRabs (/a) | There are improvements in both the Newry array and system. This means that their PLRabs show that both the Newry array and system will increase at the annual rates by −0.0096/a and −0.0096/a, respectively. Just like the Newry array and system, it will be difficult to predict any PLRrel in the PV array and system due to the seasonal variation effect noticed in weather-uncorrected relative performance loss rates. To resolve this, the weather-uncorrected PLRrel are normalised with the average cell temperature. | Arr. PLRabs (/a) | Sys. PLRabs (/a) | Performance improvement is noticed in the Warrenpoint array and there is a decrease in performance in the Warrenpoint system. This means that solar panel generation will increase at an annual rate of −0.06/a, while the Warrenpoint system shows that PV system generation will decrease at the annual rate of 0.0024/a. |
−0.15 | −0.022 | −0.0096 | −0.0096 | −0.06 | 0.0024 |
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PV Array Location | |||
---|---|---|---|
Harlequins | Newry | Warrenpoint | |
Tilt and Azimuth Angles | Azimuth: −162°, Tilt: 12° for PV array 1 Azimuth: 12°, Tilt: 12° for PV array 2 | Azimuth: −31°, Tilt: 6° for PV array 1 Azimuth: 149°, Tilt: 6° for PV array 2 | Azimuth: −125°, Tilt: 7° for PV array 1 Azimuth: 55°, Tilt: 7° for PV array 2 |
Total PV Area | 312.36 m2 | 311.04 m2 | 268.8 m2 |
Solar Cell Technology | Polycrystalline silicon (p-Si) | - | - |
PV Module Manufacturer | Renesola | - | - |
Module Rating | 260 Wp at STC | - | - |
Number of Modules | 192 | - | - |
Installation Type | Rooftop | - | - |
PV Capacity | 49.92 kWp at STC | - | - |
Module type (s) | Renesola-JC260M-24/Bbv (260 W) | - | - |
Inverter | Sunny TriPower | - | - |
Inverter Capacity [AC] | 2 × 20 kW | - | - |
Year | Harlequins | Newry | Warrenpoint |
---|---|---|---|
Average cell Temperature, Tcell_avg (°C) | Average cell Temperature, Tcell_avg (°C) | Average cell Temperature, Tcell_avg (°C) | |
2017 | 37.87 | 37.21 | 37.09 |
2018 | 38.37 | 38.14 | 37.70 |
2019 | 39.95 | 37.14 | 36.09 |
2020 | 38.06 | 36.50 | 36.79 |
2021 | 39.98 | 39.76 | 39.68 |
Harlequins | Newry | Warrenpoint | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
−1.75 | 0.44 | −1.66 | 0.41 | −1.00 | 2.17 | −1.99 | 0.66 | −1.89 | 0.81 | −1.79 | 0.79 |
Harlequins | Newry | Warrenpoint | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
−1.04 | 3.91 | −1.06 | 3.57 | −1.26 | 1.00 | −1.17 | 0.94 | −1.91 | 1.56 | −1.79 | 1.46 |
tcritical at Level of Significance, α | tcal for Harlequins | tcal for Newry | tcal for Warrenpoint | |||
---|---|---|---|---|---|---|
Array | System | Array | System | Array | System | |
6.24 | −0.15 | −1.45 | 3.10 | 7.65 | 2.51 | |
6.24 | −0.15 | −1.45 | 3.10 | 7.65 | 2.51 | |
6.24 | −0.15 | −1.45 | 3.10 | 7.65 | 2.51 |
Harlequins | Newry | Warrenpoint | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
α | tcritical | dmean | S.E(dmean) | tcal | dmean | S.E(dmean) | tcal | dmean | S.E(dmean) | tcal | |||
0.05 | 2.00 | 1.91 | 4.85 | 0.63 | 3.04 | 1.70 | 4.74 | 0.61 | 2.80 | 1.85 | 4.67 | 0.60 | 3.06 |
0.10 | 1.67 | ||||||||||||
0.01 | 2.66 |
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Okorieimoh, C.C.; Norton, B.; Conlon, M. Disaggregating Longer-Term Trends from Seasonal Variations in Measured PV System Performance. Electricity 2024, 5, 1-23. https://doi.org/10.3390/electricity5010001
Okorieimoh CC, Norton B, Conlon M. Disaggregating Longer-Term Trends from Seasonal Variations in Measured PV System Performance. Electricity. 2024; 5(1):1-23. https://doi.org/10.3390/electricity5010001
Chicago/Turabian StyleOkorieimoh, Chibuisi Chinasaokwu, Brian Norton, and Michael Conlon. 2024. "Disaggregating Longer-Term Trends from Seasonal Variations in Measured PV System Performance" Electricity 5, no. 1: 1-23. https://doi.org/10.3390/electricity5010001
APA StyleOkorieimoh, C. C., Norton, B., & Conlon, M. (2024). Disaggregating Longer-Term Trends from Seasonal Variations in Measured PV System Performance. Electricity, 5(1), 1-23. https://doi.org/10.3390/electricity5010001