After experiencing their own problems with potential induced degradation (PID), Belgium-based Edison Energy took matters into its own hands and developed the Pidbull solution in partnership with imec. Now it sells Pidbull to anyone experiencing issues with PID. As managing director Davy Verheyden explains, it is a problem solar asset owners cannot afford to ignore.
PV Tech: Why did you develop a PID specific system?
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DV: Edison Energy is a developer and owner of PV plants in Belgium. We also offer asset management services. In 2012 we discovered the first signs of PID on our own plants. We developed our own partnership with imec and investigated PID. The result was our solution, Pidbull. We started work on our own projects and got really great results so we decided to make it a commercial product. Uniquely, it is based on the experience of our own field engineers.
PID is well publicised but do you think the industry's response has been sufficient so far?
DV: In the beginning of PID you get losses on the worst-affected panels of around 20% but in total across the power plant only 2-3%. That is very difficult to detect. Not least because you can have more than 2-3% variation in radiation each year and a lot of financial institutions just look at the final numbers. But what we are seeing in countries like Greece and Italy is a lack of monitoring; some plants don't even have decent monitoring to do the detection in the first place. We are sure there is a lot of PID in the market, it's just undetected.
Why is there a reluctance to deal with PID?
DV: I think there are many factors at play. It is a new phenomenon for many investors. They don't understand it and they don't know that it can be easily reversed and also there are a lot of questions about reliability and the effect on their modules guarantees. A lot of module makers will offer a 25-year warranty and they need to be comfortable that the technology [Pidbull] will not interfere with that. A number of factors make it complex for the owners to decide apart from the fact that the detection is very hard to do if you are not familiar with the phenomenon. But if you wait long enough, a power plant may see a drop in production of 20-25% and at that stage they will start looking for a solution and they'll see great improvement!
Are investors better educated and better motivated to deal with performance issues now the industry is more mature and margins are tighter due to falling subsidies?
DV: What we see now is that there has been a lot of word of mouth with PID. Today in the market, many financial institutions are installing our solution purely as a detection method. Because you need every single percent of output to make a business case it also contributes to their risk mitigation from the outset. Looking for PID and every contributor to loss is necessary under the current financial circumstances and market conditions.
Has the shift in geographies where deployment is taking place also exacerbated the problem of PID?
DV: With PID there is the timing effect, it takes a few years before you see the first impacts and there are also the environmental conditions, the humidity and temperature. A lot of solar was installed in western European countries in 2008-2010 so they are now 6-7 years old. We are getting a lot of enquiries about projects in places like the Philippines and India where there is both high humidity and temperature. So there you see the effects very clearly. In our opinion it is also the reason that, for example in Greece, that there is more PID.
Many module companies from that era have now exited the solar market. Do you get inquiries from clients that no longer have warranties that cover their assets?
DV: Yes, we see a lot of this and have seen lots of examples of requests in the scenario where the manufacturer has gone. We have also seen instances where module manufacturers pay their customer to buy our solutions [instead of enacting the warranty]. It is a cheaper option for them than replacing the modules.
Which markets are currently providing the most demand?
DV: At this moment, Greece, Italy, Germany and the UK.
Last question, is there really such a thing as a PID-free module?
DV: We studied fifty panels used throughout Europe and only 75% passed the PID-free test. What we know about panels produced today is that an awful lot of panels are produced without, for example PID-resistant EVA because it is just a little bit more expensive. It's a really price driven market so the module manufacturers have to be competitive on price because if they are little bit more expensive, they could sell nothing. The encapsulant producers tell us that more than 50% of what they sell is not PID-free just because that version is a bit more expensive. In some cases the manufacturers will claim their modules are PID-free but the test is only done on one specific module and in reality, the bill of materials can change during the production process. One panel could be PID-free and then on the next production date a different encapsulant could be used so what you need to do is check the bill of materials for the panel used in the test and the bill of materials for all their panels. This is hard to keep track of.
As voltages increase, we are now seeing 1500V used more often, which is a disaster for PID! Instead of taking 3-4 years to present it takes two years.
Find out more about the results of the PID performance test by downloading the full technical paper for free.