Reusing and efficiently recycling PV modules: This is how we bolster the circular economy in the solar industry

By commissioning a photovoltaic system, you are doing something great for our environment. This is not only due to the positive energy balance, but also to the excellent recyclability of solar systems. Crystalline PV modules, which are now nearly exclusively installed in Switzerland, are free of hazardous substances that could harm humans or nature when recycled. In addition, a PV module contains a number of recyclable materials that can be reused. On average, 75 per cent of a photovoltaic module can be recycled.

From downcycling to efficient recycling

Despite the above-average recycling quota: Even photovoltaic systems do not yet fully satisfy the requirements of a modern circular economy. The life cycle of a PV system, from production through the utilisation phase to recycling, still remains linear today and is not circular, as would be the case in a perfect circular economy. This means that the material flow in the entire value chain of a PV module cannot yet be closed completely. There is not yet a loop in which the materials can move infinitely and be used again and again.

Even though a number of valuable materials from decommissioned photovoltaic systems can be reused through recycling, the life cycle is still linear and not circular.

Although three quarters of all the materials that make up a PV module can be recycled, not all of the components maintain their original value. Downcycling is the technical term for this. For example, the valuable silicon is reused for producing building insulation material from glass wool. One of the major challenges for the future is to recycle the silicon to such a high purity level that it can be used again for manufacturing PV modules.

Extending life through secondary use

Another key goal of the circular economy is to extend the service life of a product as much as possible. As paradoxical as it may sound, the service life of a PV module – which is already very long – stands in the way of this endeavour. PV modules lose about 0.5 per cent of power per year, which is quite low. After 20 years, they still hold 90 per cent of their initial power.

This exceptionally long product service life is offset by the rapid technical progress in the development of new PV systems. As a result, existing PV systems are hardly ever repaired and are disposed of when it is not absolutely necessary to do so. The average service life of a PV system today is 25 years. Some PV systems could be extended by 5 to 15 years through specific measures.

Experts estimate that about half of the PV modules scrapped each year would have enough power left over to be reused as second-hand modules. Using such modules would be particularly useful where solar energy is only used for a short period of time: for example, on temporary car parks, mountain huts or old buildings that will soon be torn down – or anywhere with insufficient funds for a new system.

Reusing thanks to a digital passport

In order to further improve the circular economy in the solar industry and minimise future waste by increasing the secondary use of PV modules, SENS eRecycling and Swissolar have teamed up with the Bern University of Applied Sciences and other partners from the Swiss PV industry. We are working together to complement the current process of PV module pick-up, collection and recycling with an additional test procedure designed for reuse.

This project focuses on the development of a digital passport on which all data concerning the manufacture, possible repairs and the current performance of a PV module are stored. This data serves as the basis for deciding whether the discarded module needs to be recycled as usual or whether it should be labelled and sold at a reasonable price on the second-hand market.

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