By Gina Evangelidis
Germany’s largest thin-film PV power system, Waldpolenz Solar Park in Leipzig, contains 550,000 thin-film modules that at end of life will require recycling. This is a true reflection of a steadily growing PV power industry and with this growth comes a huge responsibility for the modules that are created to facilitate energy supply.
Disclosure: I am a keen advocate for renewable energy and sustainability. It simply does not make sense to me that, at a time when technology is advancing at such a phenomenal rate, we would continue to create conventional energy systems that are wasteful or damaging to the environment. And, if given the choice, it seems absurd that we would choose to use a finite resource when we can harness the infinite power of the sun. However, I do accept that the modules are not infinite; they have potential to become waste in huge proportions.
There are companies which specialise in recycling PV modules, with over 13,000 tonnes of solar energy products recycled since 2010. Let’s take the PV CYCLE Association as an example: PV CYCLE is a legal compliance and waste management service, dealing with products that fall under WEEE (waste electrical and electronic equipment) and Battery Producer Responsibility legislation. PV CYCLE is representative of its members—PV manufacturers, importers and installers, and claims to be the first to offer take-back and recycling solutions on a global level for all types of PV technology.
In contrast, non-silicon based PV uses chemicals to separate the materials, employing some mechanical techniques later to further refine the materials recovered. These boast a 97% recycling yield. Both silicon based and non-silicon based recycling methods go way above the 70% overall recycling efficiency in the WEEE industry.
PV materials’ recovery is not a profitable venture. This is, in part, because of the low volume of waste, but other factors, such as transport costs and the tools required to recycle, currently still outweigh the potential profit from trading the recovered materials. This is why PV CYCLE works through a collective approach throughout Europe; they want to boost volumes and increase the economic viability of the process through economies of scale.
Indium, selenide, gallium, silicon dioxide and cadmium telluride can all be recovered from PV modules, alongside elements such as aluminium and copper, which plays a huge role in resource sustainability.
PV CYCLE state that ‘a separation by technology and particularly from other waste streams is key to a high recycling output.’ This output can then be used in glass packaging or insulation, totally new products, plastic products, aluminium/copper products and more. A maximum of 5% of recovered raw material ends at landfill, if applicable at all.
Silicon based and non-silicon based PV are recycled through differing technologies, but both yield impressive results. Silicon based PV modules use a mainly mechanical process, whilst non-silicon based PV uses a predominantly chemical process.
The silicon based high yield PV recycling process separates the frame, junction box and cable to allow differing materials to be recovered on separate recycling lines. Through shredding, milling and various thermal and mechanical processes around 90% of a silicon based module is recycled. This figure is likely to increase as PV CYCLE has recently seen a new recycling record of 96% in industrial-scale performance.
Another key cost stems from WEEE. Simply falling under WEEE adds cost: for administration, product labelling and campaigning responsibility – amongst others. Of course, these costs will vary from business to business, but they can place an additional burden on a very essential industry.
On average, PV modules have a healthy lifespan of around 20-25 years, and though the PV recycling industry is relatively small with around 12 companies in the business, it will surely grow with the increasing demand. This growth gives the industry a real opportunity to show commitment to sustainability.
References:
1. PV Module Recycling: Industry Standards & Best Practice, PV Cycle Association, 2016, http://www.pvcycle.org.uk/
2. SolarPower Europe’s press release on March 3rd 2016, http://www.solarpowereurope.org/
3. Minor Metals in Renewable Energy Technologies, MMTA, http://www.mmta.co.uk/uploads/2014/09/22/160613_renewable_energy_technologies_and_minor_metals.pdf
4. Image Source: PV Cycle Association
