
How utility-scale solar PV plants perform over time

In an attempt to evaluate performance before plants face impacts due to degradation, LBNL's research determined that actual first-year performance is slightly lower than ideal modeled first-year performance with a median difference of 0.4%. More than 60% of plants fell short of their ideal modeled first-year capacity factor. At least 80% achieved at least 90% of their modeled performance.
Overall, the average utility-scale solar PV was found to experience a performance loss of -1.23%/per year. Plants built since 2014 have declined in performance less (-1.1%/per year) than plants built before 2015 (-1.2%/per year). The report noted that the statistical difference is significant.
The study also found an increased prevalence of tracking equipment in utility-scale solar PV plants, amounting to 66% of the total sample. Performance among fixed-tilt plants declined less (-1.2%/per year) than plants with single-axis tracking (-1.3%/per year).
Plants using thin-film modules also were found to have declined less (-1.0%/per year) than plants using Si modules (-1.3%/per year).