Older modules for reuse, not refuse


Imec R&D manager Eszter Voroshazi has led the institute’s research work on second-life pathways for solar PV modules.

Image: imec

Why do you believe that it is important to facilitate the development of a second-life market for solar PV modules?

It is crucial in the sense that we can make PV affordable for communities – it is still too expensive for many. Reuse is the most sustainable option in terms of a circular business model. When big PV farms are damaged by weather, a certain percentage of the whole string or site gets dismantled, and at least 40% to 50% of the modules are only a few years old and are of very good quality. There is a good 15 to 20 years of reuse that is still possible.

Where would the modules be reused?

Based on the economics, these modules would mostly go to low-income countries. But they can also go to projects in eastern Europe – so ‘low income’ in a wider sense.

What is holding up this kind of reuse?

A very big challenge is that there is rarely quality and safety testing of second hand modules. It depends on the operators, whether the used modules are sorted and tested, and how. After being shipped and handed over to distributors, by that time the traceability and professional distribution chain breaks down – you don’t know where the modules end up. Relevant legislation [to enable solar reuse] should impose minimum quality testing and apply certain rules on the distribution chain. But I really see a great benefit of reuse globally.

And what is the great benefit for end-use countries?

Because of the costs – every cent matters. Reuse modules, if retested and sorted, can be fine in smaller installations with lower voltage.

You mention legislation – why is it necessary?

There are a lot of technical arguments for reuse, but legislation and a good technical surrounding are needed. When you ship all of these modules to the ‘south’, there is one very big question or warning: There is no recycling infrastructure for PV modules in these countries. What will happen to these modules [at end of life]? It is unlikely they would be shipped back to Europe or the United States for recycling. Any deployment to the ‘south’, whether reuse modules or brand new, should really be contingent on the local authorities putting in place takeback schemes, and to establish local recycling.

What kind of installations are well-suited to reuse modules?

If the modules are PID-prone or have slight defects, you could install them at smallerscale residential installations in low-income countries. At utility scale it will come down to the numbers: If labor and land are cheap, then a good quality second hand module can go to utility scale, but the financial backing might not follow without a quality certification scheme, there is no need for full IEC certification of second hand modules.

It certainly is technically possible; I really don’t see a problem. But I am not sure if they can be bankable. Liability of the different actors should be made clear.

What about module refurbishment? What kind of technical options are available?

For bypass diode failure or junction box failure, they happen frequently in the field and can be repaired. Anti-reflective coating can go away in certain climates, and I know that [Dutch materials company] DSM is preparing recoating material and techniques. Backsheets can also be repaired.

Even with second hand modules, these repairs can be done in the field. Sending a module back to the factory is not economically viable, but field repair would make more modules attractive and viable for reuse. And it will create jobs.

If in Europe you do the sorting, some modules will be as good as new, when in low-income countries many other modules can be repaired.

In a bigger business setting it would make sense, create jobs and educate people locally. For an extremely price sensitive product, repair close to the reuse location would make a lot of sense. Some companies like SecondSol in Germany are doing a very good job and can afford even higher repair costs for ‘rare’ second hand module types.

There is indeed a small, niche market for repaired modules for the FIT installations, due to strict regulations. But other than that, there is no technical reason for this. We do hear that for some rare modules there are crazy high prices, which occur when one or two modules have failed in a string and need replacement. But it is a small market that will die when the FIT period ends. pvXchange and SecondSol are operating with these clients, and they are also gradually increasing their shipments outside of Europe.

Are you confident that reuse markets will happen?

I am a bit hesitant to say yes while there is no clarity on the bankability question. Then the other point is how much lower new PV module prices will go. We all thought in the past that we had hit the bottom, but we have not. If we want to make module reuse happen there needs to be legislation to encourage it.

I see reuse as being technically feasible and there is no doubting the need for it in the end-use countries. But whether it will really happen I am not 100% convinced.

For the fact that there is zero legislation in place in most countries around the globe, the trust in reuse modules is limited. It follows then that the banks and project developers will also lack trust, and that makes it doubtful at to whether it will fly.

Imec is a part of the Circusol program (see pv magazine 06/2020). How does your work there intersect with a potential reuse market?

We are trying to make it happen in Europe. But I think the whole ownership – who owns the modules and the reuse sites – needs to change and this would help overcome the trust question. But for what needs to happen in broader deployment to lower-income countries, the whole business model might have to change. One could even imagine that the reuse company will be responsible for shipping, owning, operating and also takeback to ensure there is good traceability and end-of-life treatment. But to do this we need to integrate the entire value chain – and at present they are usually separate actors.

This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.