Power plant owners are increasingly worried about PID of their modules as more and more reports about significant yield losses caused by PID are hitting the market. ENcome Energy Performance, a leading manufacturer and constructor-independent service provider for PV power plants, has also been approached by module manufacturers who want to know about the frequency of incidents and more details on triggering factors in order to determine appropriate warranty provisions. “The industry already knows much about factors that accelerate PID, but unfortunately, according to current knowledge, it still seems that the effect can occur at any plant with crystalline modules and ungrounded, transformer-less inverters”, explains Dr. Robin Hirschl, CEO of ENcome Energy Performance, and continues: “As this general information does not allow for specific project-related advice, ENcome has joined forces with leading research institutes for further investigations in order to derive more feasible conclusions for both, module manufacturers as wells as power plant owners.”
PID can be detected already in very early stages with quite simple means such as IV-curve measurements or infrared pictures. At this stage impact on the plant performance might not be noticeable, but as PID is a continuous process it can be expected that such will eventually occur. Even more, in such early stages PID is easily reversible and the affected plant can be equipped with measures to prevent the re-occurrence. “As identification and counter-measures are simple in early stages but become impossible once a plant is heavily affected, it is in the interest of both, plant owners and module manufacturers to gather the PID-state of their plant regularly”, explains Hirschl. The upcoming scientific investigations will also identify when it is safe to say a plant will not be affected any more by PID.
As PID is not merely of interest for academic conferences but a critical technical problem of major commercial concern, ENcome Energy Performance supports moving the issue to a more commercial level, delivering results that are of immediate help to plant owners and manufacturers.
Potential-induced degradation (PID) is a loss of system power, mostly caused by leakage or stray currents occurring at high voltages in PV modules. Modern PV installations commonly reach up to 1 kV at the string ends; as the metallic frames of PV modules have to be grounded for safety reasons, the individual string units become voltage biased against their frames, causing leakage currents between the frames and the solar cells. If the inverter is also grounded the long time performance remains unimpaired; if, as it is increasingly the case, an ungrounded inverter without transformer is used, PID may arise.
ENcome Energy Performance was founded by a team of three managers that bring together decades of experience in renewable energy business. Well skilled engineers ensure the best yield for every renewable energy park in any grid environment. ENcome offers all services along the asset lifecycle with one single point of contact. Together with subsidiaries and a partner network ENcome covers its service portfolio across Europe.