Fraunhofer ISE
monitoring Measuremens © Fraunhofer ISE |
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In practice PV systems show considerable differences in energy yield even if their rated power is comparable. These differences originate from several factors like selected PV modules and inverters, the combination of components and installation site characteristics. For PV modules influences are tolerances in power rating, their efficiency curve, and mismatch losses. For inverters the main influences consist in their efficiency curve, operational availability and self-consumption. Further important aspects are among others a careful sizing of system components, a good overall system design and an optimised module orientation.
For the purpose of comparison between PV systems the Performance Ratio (PR) proved to be an appropriate measure for the overall system quality. Modern PV systems achieve PRs of 80% whilst some exceed 85% depending on cell technology and climatic conditions.
This website presents PV systems from employees of Fraunhofer ISE.