This report presents a performance analysis of 75 photovoltaic systems based on photovoltaic (PV) system production data collected as part of a Federal Energy Management Program (FEMP) Federal PV Performance Assessment project combined with co-incident insolation and ambient temperature to analyze how actual performance compares with a performance model.
FEMP collaborated with 16 federal agencies and sub-agencies to collect the information required to analyze the performance of each system. The data is analyzed for key performance indicators, availability, performance ratio, and energy ratio by comparing the measured production data to model production data. The System Advisor Model (SAM) combines a description of the system (such as inverter capacity, de-rating for temperature, balance-of-system efficiency) with environmental parameters (coincident solar and temperature data) to calculate predicted performance. The performance metrics are calculated by lining up the measured production data with the model estimate on an hour-by-hour, day-by-day, or month-by-month basis.
A report with system description, photo of the system, special assumptions made for the site, graph of measured production and model production, table of key performance indicators, and links to operations and maintenance resources that might improve performance was produced and delivered to site and agency staff with a short online briefing.