Why PID Prevention Is an Essential Risk Management Strategy
PID (Potential Induced Degradation) can severely damage the performance of PV plants, and according to TÜV Rheinland, PID is the “number one earnings killer”. Research also shows that the higher the voltage a PV module has, the faster and more severe the degradation. Fortunately, the devastating effects of PID can be avoided with a proper PID prevention strategy in place. This helps PV modules function more productively and also helps stakeholders avoid non-refundable damages and unnecessary losses later on.
Why PID Is a Major Risk Factor
All solar plant operators should account for PID in their risk management strategies. Luckily, knowledge of the PID phenomena has grown significantly over the years. As PV plant stakeholders, both internal and external, continue to increase their awareness of PID, the phenomenon raises a lot of red flags for all involved parties in terms of preventing and managing risk.
PID is a common occurrence where degradation can be built within photovoltaic modules, if not properly prevented. PID can cause both severe operational and financial losses. For instance, in a plant with a capacity of 55MWp, PID could cause losses of over $544k annually with a 3% degradation rate. And that loss is only noticeable after PID has been discovered.
PID may also be considered as extra degradation or excluded completely in the PV module manufacturer's production warranty, leaving a plant without loss coverage and future protection.
| Basic details | Residential | C&I | Utility-Scale |
| Plant Capacity | 20kWp | 630kWp | 55MWp |
| F.I.T. (US$) | $0.4 | $0.25 | $0.13 |
| Yearly Yield Factor (kWh/kWp) | 1,650 | 1,650 | 1,650 |
| Annual Income | $14.8K | $311K | $13.6M |
| PID degradation (%) | 5% | 4% | 3% |
| Estimated Anti-PID investment | $600 | $6,500 | $120K |
| Additional Annual Revenues | $600 | $12.5k | $544k |
| ROI (years) | 0.9 | 0.62 | 0.37 |
Why You Must Act Now
It may take a few years to accurately and clearly diagnose the PID phenomena. In the beginning stages of PID, the negative effects of it can be written off as other possible reasons for degradation, like weather, soiling, maintenance, irradiation levels, LID, and other issues. However, once the degradation is too severe to otherwise explain, then on-site, lab investigation or drone tests are performed to locate the degradation reason.
By the time it has been accurately diagnosed, the PID can have an overall negative effect on plant production totaling 10% to 20%. At that point, the PV modules on the end side of the strings are already severely degraded.
Once a plant reaches this stage, treating the PID and preventing further losses will incur high and unrecoverable costs. The effect on the project financing after PID has occurred could be drastic as well as frustrating since it could have been prevented with the right planning. If you only then install anti-PID devices, it may take meaningful time to recover the PID, and thus incur an additional loss of revenue.
Today floating PV, high voltage PV, and bifacial PVs are also becoming more common, all of which might experience heightened PID. That's why prevention is now all the more important. That’s why you must act on Day 1.
The Residual Effects of Improper PID Prevention
Today, not only EPCs look at PID preventive measures from a risk management point of view, but investors, banks, and insurance companies do too. Not having a solid approach to preventing PID significantly increases investment risks, and it can lengthen the ROI period while decreasing profit margins.
This means that ignoring the risk of PID could steer the investment and profits of a plant off track and lower overall confidence in the project. Furthermore, project financing, bankability, yield, and revenue insurance are less accessible when PID prevention actions have not been taken during the planning stage of a project.
And that’s true even for PV plants that utilize modules that are advertised as PID-free. This is because PID-free modules (meeting IEC62804 Standard) PID have a permitted degradation of up to 5%. But plants shouldn’t be willing to give up 5% of a plant’s overall lifetime yield, especially given how small margins can make huge differences.
PID Prevention Is More Efficient Than Remediation
The benefits of proper PID prevention are clear by themselves, but understanding the PID remediation process makes them even clearer. By the time PID is detected, the plant has already suffered significant accumulated losses. However, the plant must also go through the process of demonstrating to the PV module manufacturer that the degradation is indeed PID, negotiate the remediation process with the manufacturer, and spend additional resources to unmount, pack, and recycle the affected modules.
All of the above costs will not be returned to the investors, owners, or EPCs. Incorporating PID prevention into a plant’s overall risk management strategy from the beginning will significantly reduce or remove these costs entirely. And by doing so, stakeholders can focus their efforts on optimizing the plant while proactively minimizing performance and financial losses.
The Recommended Strategy
Today, we see many tenders for new PV plants where the EPC has to include an Anti-PID solution (integrated with the Inverter, or stand-alone).
PID is here to stay, regardless of whether the “PID Free” module type (Monocrystalline, Polycrystalline, N-Type, P-Type, etc.) is in use.
Introducing the Anti-PID solution at the design phase, as part of the EPC work, will improve the Total Cost of Ownership and will guarantee meeting the business plan over the life cycle of the PV plant. It is a sort of insurance with a relatively small investment.