2nd life deployment of PV panels: Is it worthwhile?

Life-time extension of products, components and materials, realized via re-use and repair is one of the cornerstones of a circular economy. Over recent years there has been an ever-growing deployment of PV, leading to an expected increase in revamping/repowering of installations in the future. This means many PV panels will be decommissioned before reaching the end of their technical lifetime. One of the Circusol aims is to extend the use life of PV installations by developing 2nd life deployment pathways.

Within Circusol, it was assessed whether and under which conditions lifetime extension is favourable from an environmental perspective. Also, the business case for 2nd life PV was evaluated. A trade-off is to be made here, as new panels are more efficient and allow for more production of solar energy and additional repair and transportation activities might be required in the case of lifetime extension via 2nd life deployment.

Factors influencing PV panels' lifetime extension

The environmental and financial potential of lifetime extension of PV panels depends on different factors, such as:

  • State of health of the PV panel
  • Remaining power density
  • Location of re-use
  • Technology evolution leading to more efficient PV panels

Of course, also other aspects such as available installation area, legal aspects, consumer trust, market acceptance, aesthetics play a role in the decision-making process. These are, however, not taken into account for the environmental and business case analysis.

Environmental point of view

VITO's analysis revealed that even for panels aged 15 years and more lifetime extension is preferred from an environmental point of view over replacing with or installing new more efficient panels [1]. The conclusions are valid as well for a re-use case, when modules are transported within the same geographical area and when only small repair activities, like the replacement of a junction box, are necessary. The analysis was limited to simple repairs. Complex repairs are not included because current panels are not designed for disassembly. More extensive repair options are about to rise, amongst others, one of the Circusol partners is working on the design of better repairable PV modules.

Financial aspect

The financial viability of 2nd life PV panels strongly depends on its remaining power density and lifetime. For a business case to be present, the maximum Willingness To Pay (WTP) for 2nd life PV needs to exceed the costs associated to the supply of 2nd life PV (for inspection, handling and potential repairs). This is the case for healthy panels up to 10-12 years old and for panels with minor defects like diode or cable failures in their early years. There is no business case for 2nd life deployment of panels with more severe defects. There are, however, some ‘buts’ to take into account. The analysis was performed from a theoretical perspective and the conclusions might be heavily influenced by case-specific parameters like limited surface availability. Additionally, costs related to testing and recertification were omitted in this analysis due to a lack of data available. Improved insight into the PV panel rehabilitation process and its related costs are required.

Environmental impact per functional unit with different panel service lifetime, over a 30-year period. Panels with 10 year service lifetime need 2 replacements during the 30-year period, panels with 15 year service life need 1 replacement during the 30-year period. Environmental impact is expressed in a single score (mPts), covering 16 different environmental impact categories (Product Environmental Footprint method). As a sensitivity assessment, it was checked if a possible improvement in the environmental impact of the PV panels would change the conclusions.

The WTP for 2nd life panels, expressed in €/kWp heavily depends on the remaining power density and lifetime of the panels. Taking into account a technical lifetime of 30 years the remaining lifetimes of panels from 2010, 2014 and 2017 are - respectively - 20, 24 and 27 years. Obviously, the remaining power density for more recent panels is higher as well, leading to an increased WTP which well offsets the costs incurred on the supply side. 

 

[1] Multi-Si panel, 240 W; average yield at an optimal angle: 1090 kWh/kWp (based on the average irradiation for Europe); degradation rate of 0.7% and an innovation speed of 2.6% per year

 

Author: 

Anse Smeets, Circular Economy Researcher at VITO

Co-authors:

Neethi Rajagopalan, R&D Analyst, Sustainable Built Environment at VITO

Karolien Peeters, Researcher Built Environment & Smart Cities at VITO

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