As solar energy rapidly scales up globally, ensuring its efficiency and affordability over the long term is essential. New research led by Alberto Boretti and Stefania Castelletto delves into a critical aspect of solar power economics—performance degradation in photovoltaic (PV) systems. By re-evaluating degradation rates in large solar plants, this study brings promising insights: the degradation rate of newer solar PV installations is far lower than previously assumed. This finding could directly lower the Levelised Cost of Energy (LCOE), enhancing solar’s economic appeal.
The Challenge: Accurately Predicting Solar PV Degradation
For years, solar PV systems were assumed to degrade at a rate of around 0.5% per year, leading to reduced power output and higher maintenance costs over time. This assumed degradation rate played a significant role in calculating the LCOE, a crucial metric for assessing the financial viability of solar projects. However, as PV technology improves and maintenance practices advance, this standard degradation estimate may be overly conservative, especially for new, large-scale installations.
New Findings: Lower Degradation Means Lower Costs
In analysing data from 53 recent large-scale solar PV plants across the United States, Boretti and Castelletto found that annual degradation rates in these plants range from 0% to 0.29%. This is significantly lower than the industry-standard assumption of 0.5%, demonstrating that newer plants, when managed and maintained effectively, experience less performance drop-off over time. This breakthrough directly impacts LCOE, which could fall by up to 2.1%—a cost-saving that makes solar projects even more financially attractive.
Methodology: Advanced Data and Long-Term Analysis
The study draws from comprehensive real-world data on energy production, resource availability, and weather conditions over nearly a decade. Using the National Renewable Energy Laboratory’s System Advisor Model (SAM), the researchers tested the degradation rates without needing to account separately for year-to-year weather and irradiance fluctuations. This streamlined analysis revealed that degradation rates in modern PV plants are far more stable than previously expected, underscoring advancements in solar module design and maintenance protocols.
Practical Implications for Solar Energy Expansion
The lower degradation rate suggests that PV systems can maintain higher efficiency over their lifetime, reducing operational costs and enabling more competitive bids in energy auctions. For investors, this finding indicates a more predictable return on investment, while policymakers can leverage these lower LCOEs to support broader solar deployment without excessive subsidies. Ultimately, this research supports solar’s position as a robust, cost-effective solution in the global energy landscape, making a significant contribution to the green energy transition.
Source
Annual relative performance degradation in photovoltaic solar plants, Solar Energy Advances, 2024-18-10
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