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Closing the loop: Cradle to cradle design for PV modules

The recycling of PV modules is an unsolved problem. The working group led by Ian Marius Peters from the Cradle-to-Cradle PV project is researching solutions to this problem. The following fact sheet presents the key points of the project.

What is researched?

  • The group is involved in the development of new solar cells and solar module architectures that enable selective separation between materials or components.
  • One example of this is perovskite solar cells. Perovskites are a family of materials that show high potential for photovoltaic applications and are currently at the beginning of commercialization.
  • In contrast to conventional silicon solar cells, perovskites can be deposited from solution. This property makes it possible to establish wet-chemical processes for redissolution and material recovery in order to recover the starting materials with high purity.

How is it researched?

  • Our approach is shown in the diagram.
  • First, a solar cell is manufactured from a set of materials. This solar cell is then measured to determine the conversion efficiency.
  • In parallel, a larger-area structure with the same composition is produced. This step is necessary in order to have enough material for a recycling process; a single cell would be unsuitable for this.
  • The large structure is then selectively deconstructed, layer by layer, and the materials from which the individual layers are made are recovered and processed.
  • The recovered materials are then used to produce a new solar cell.
  • If the process is successful, the efficiency of the recycled solar cell differs only marginally from the original.
  • This approach is supported by detailed material characterization (crystal structure, degree of purity,...).

What is the aim of the project?

  • The aim of the project is to develop fully circularly recyclable solar modules in order to separate materials in a targeted manner and efficiently recover valuable substances. This closes the material cycle in the PV industry.
  • Circular solar modules must also be economically attractive. This requires them to function efficiently, for a long time and stably, and to be easy to separate at the end of their service life.
  • Activities began at the end of 2023. The first experiments have shown that more than 99.9% of the mass of a solar cell can be recovered and reused.
  • The project is funded by the European Research Council (ERC) as part of a Consolidator Grant, which will be used to set up the “Sustainable Photovoltaics” group at the Helmholtz Institute Erlangen Nuremberg (HI ERN).

[Translate to Englisch:] Das Team des Forschungsprojektes Cradle-to-Cradle PV

What is the benefit for society?

  • Efficient recycling prevents millions of tons of waste from old solar modules from ending up in landfills. In addition, the environmental impact of extracting and processing new raw materials is further reduced.  
  • Access to recycled materials reduces the need for new raw materials. This secures the supply of raw materials in the EU and increases the resilience and sustainability of the energy system.
  • The recovery of valuable materials such as silicon, aluminum and rare metals from PV modules can reduce the cost of manufacturing new PV modules.
  • Ultimately, a circular design that takes into account the cost, lifespan, reusability and recyclability of solar modules is the best option to make renewable energy more sustainable than any other energy technology before.
The sun rolling high through the sapphire sky keeps great and small on the endless round.
Elton John, Circle of Life