Minimising the Uncertainty in Performance Loss Rate Calculation for Photovoltaic Systems: A Clustering-Based Year-on-Year Approach

Photovoltaic (PV) systems are a cornerstone of renewable energy, with a global installed capacity of 1.6 TW in 2023, projected to reach 4.2 TW by 2030, according to the International Energy Agency. This growth demands significant investments, underpinned by accurate and reliable data to assess risks and returns. Precise yield assessments play a vital role in determining insurance premiums and mitigating financial risks, making them essential for the bankability of PV projects. However, environmental variability introduces significant uncertainty in the calculation of the performance loss rate (PLR), a key metric for evaluating long-term system reliability and long-term yield assessments. This study introduces a clustering-based year-on-year method that ensures like-for-like comparisons of operational days under similar environmental conditions. Applied to two datasets, the proposed method achieved a 2.6-fold reduction in monetary uncertainty, lowering it from A$1,147,000 (equivalent to A$11.47/kW/year) to A$423,000 (equivalent to A$4.23/kW/year) per year, representing a 63% improvement. By enhancing PLR estimation accuracy, the method reduces financial risks, strengthens stakeholder confidence, and supports the global expansion of PV systems.