Photovoltaic System Performance, Degradation Rates, and Levelised Cost of Energy Across Three Panel Technologies

The European Union's REPowerEU plan targets 600 GW of installed solar photovoltaic capacity by 2030, requiring an unprecedented acceleration in deployment across diverse climatic, regulatory, and grid-integration contexts. The long-term techno-economic performance of photovoltaic installations — encompassing annual energy yield, performance ratio, degradation rate, and levelised cost of energy — varies substantially across panel technologies, mounting configurations, and geographic locations in ways that are not fully captured by short-term laboratory measurements or manufacturer specifications. This study presents a five-year field performance assessment of 84 photovoltaic installations across Germany, Spain, and Sweden, covering three panel technologies — monocrystalline silicon (mono-Si), polycrystalline silicon (poly-Si), and cadmium telluride thin-film (CdTe) — and three mounting configurations — fixed tilt, single-axis tracking, and dual-axis tracking.Mono-Si fixed-tilt systems demonstrated the highest mean performance ratio (PR=0.84 at installation, declining to 0.80 at sixty months), while CdTe thin-film showed the lowest degradation rate (0.3% per year vs. 0.5% for mono-Si and 0.5% for poly-Si). Single-axis tracking increased annual energy yield by 18.4–22.6% over fixed tilt across all technologies. LCOE for the best-performing configuration (single-axis mono-Si) reached EUR 34.2/MWh at the German sites under current financing conditions — competitive with all conventional generation sources and enabling direct grid parity across all study locations without subsidy