In a development that may enhance the appeal of solar energy facilities as an asset class, data collected on photovoltaic systems financed with ARRA Section 1603 grants indicate that the systems have performed better than expected over the initial five years of operations.  In April, the National Renewable Energy Lab published an analysis of data collected on more than 48,000 systems financed with 1603 grants.  On average, the system have produced 2% to 5% more energy than their targets.  The data also show that PV systems perform reliably over time.  Systems with identifiable problems comprise less than 10% of all systems.  Moreover, this percentage tends to decline over time as initial obstacles (e.g., permitting delays, out-of-the-box equipment flaws) are overcome.  The percentage of systems experiencing continuing performance-related problems was only 1% to 3% in any given year.

https://financere.nrel.gov/finance/content/1603-data-lifts-veil-pv-system-performance