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Written by: Pia Alina Lange | Published:
Frameless PV modules

With solar energy systems being increasingly adopted, photovoltaic module waste is a growing concern. Pia Alina Lange, head of public affairs at PV CYCLE, the industry’s take-back and recycling programme, reports on recent leaps forward in tackling this waste stream

With more than 100 gigawatt (GW) of installed photovoltaic (PV) capacity in Europe today, according to SolarPowerEurope’s 2015 Solar Market Report – or about 10 million calculated tonnes of PV modules – waste is only a question of time in this fast-growing market. Contrary to most other waste products, however, time is key.

PV modules have a technical lifetime of 25-plus years, and product and performance guarantees of usually 10 and 20 years.

To date, PV CYCLE – the industry’s take-back and recycling programme – has collected and treated approximately 15,000 tonnes of the energy-producing solar panels, more than all other programmes combined. Most were installation, weather or transport damaged; some came from guarantee or warranty cases. PV modules that had reached the end of their technical lifetime made up only about 1%.

Low waste volumes and long lifetimes have discouraged many treatment facilities from investing in own recycling lines for PV modules, but shortsighted investment plans cannot fulfil the expectations of many.

It comes as no surprise that PV module recycling is a relatively young, niche industry. Dedicated solutions were put in place between 2005 and 2007, with First Solar’s recycling programme for its CdTe-based PV modules in 2005 and PV CYCLE’s waste management initiative for any type of PV technology in 2007. Today, there are about a dozen recyclers actively working in PV module recycling worldwide. PV CYCLE has partnerships with most of them, providing our members and their customers access to best practice and technological advancement.

Capacity

While annual waste volumes are far from the capacities of traditional recyclers today, industrial-scale solutions are crucial to grow with the steadily increasing quantities. In 2010 when PV CYCLE ramped up its operations, only about 80 tonnes were collected and treated. Within one year the annual treatment volume rose to 1,429 tonnes, reaching an all-time high in 2012 with 3,762 tonnes.

Since then waste volumes have evened out at approximately 2,500 tonnes per year. It is expected that within 12 years from now, depending on the maturity and size of the market, waste from PV projects will make a significant jump upwards.

While calculations supplied by SolarPowerEurope report four million tonnes of PV module waste in Germany alone, exact figures and time periods are difficult to predict – a burden for treatment and transport companies specialised in PV module waste.

Recycling technologies

All PV technologies are equally suitable for recycling, with PV CYCLE recycling rates beyond legal and industry standards. Specially dedicated solutions that avoid contamination with other products or materials ensure the correct collection of PV modules, and include a comprehensive recycling approach – significantly contributing to the preservation of valuable resources and decreasing the environmental footprint.

Glass, aluminium, copper, silver and certain semiconductors can be recovered for the production of new materials. Only plastics from the EVA foil cannot be recovered for further use, so goes into energy recovery. As waste volumes increase, so is the marketability of EVA foil expected to improve.

To ensure high recycling rates, PV CYCLE distinguishes between PV technologies using silicon semiconductors and those modules based on cadmium telluride (CdTe), copper/indium/gallium/selenide (CIGS) or other non-silicon-based materials.

Silicon-based PV

In a mainly mechanical process, the individual materials used in silicon-based PV modules are separated and step-by-step refined.

In a manual or automated process, the frame, junction box and cables are removed to be processed in separate recycling lines. The glass-laminate is then shredded or milled to access the different layers of a PV module.

In various sorting steps the glass and copper strings can then be separated from the EVA foil. In subsequent steps the individual materials are further refined. The shredded silicon flakes, a combination of EVA laminate and the silicon cell, are sent for micro-recycling, applying mechanical and thermal processes to further split the materials, or tests.

For silicon-based PV, existing recycling techniques from the flat-glass or WEEE recycling industry can be applied. The laminated product composition is comparable to car windscreens, TV sets and computers.

PV CYCLE’s network recycles approximately 90% of a silicon-based PV module on average.

Continuous improvement and intensive R&D recently led to a new record in our silicon-based PV recycling – a 96% rate.

Low-yield techniques usually only include the separation of the frame and junction box, both good sources for valuable materials such as aluminium and copper.

Non-silicon-based PV

In a mainly chemical process, the individual materials are separated.

Certain processes also use upstream shredding to access the materials more easily. In next steps the recovered materials can be further refined, using both chemical and mechanical techniques.

Recycling solutions for non-silicon-based PV include, for example, techniques from waste water treatment or battery recycling.

Expert recyclers used by PV CYCLE can already achieve average recycling rates between 90% for silicon-based and 97% for non-silicon-based PV modules, per input weight. However, recycling rates for industrial PV waste treatment are almost non-existent in other regions of the world.

PV CYCLE, through its own initiatives or joint R&D projects, is working on intensifying knowledge transfer with recyclers outside of Europe to ensure viable recycling solutions for PV modules across the globe.

Meeting standards

However not all recycling solutions available on the market meet the current benchmark set by PV CYCLE.

Many alternatives do not go beyond pre-treatment, which usually only involves the separation of the frame and junction box, or don’t have the necessary permissions to treat (PV) waste.

PV module waste is not considered as hazardous waste in Europe (except for Spain), China, the USA or Japan. PV modules are also excluded from the RoHS (Restriction on Hazardous Substances) Directive.

Some countries require specific permits for the recycling of PV modules, however. For example, only WEEELABEX-certified recyclers can accept and treat PV modules in the Netherlands.

Most importantly, though, PV modules fall under the scope of waste electrical and electronic equipment (WEEE) legislation. Since 2014, EU member states have required PV companies to organise their products’ take-back and recycling and implement eco-design programmes in order to help facilitate the transition to a closed-loop economy.

Our longtime experience has proven one thing: while PV module recycling is little different from other e-waste treatment, it is highly recommended to collect PV modules with two aspects in mind:

• Only PV modules containing all components can be recycled as PV module waste. Broken modules or modules damaged in fire can only be recycled if all components are available in their original form.

• Separate collection of silicon and non-silicon-based PV modules to erase superfluous cost through additional sorting and contamination with other waste/materials.

PV CYCLE therefore champions an industry-led solution with dedicated collection. Professional and PV-experienced collection points and transporters can generally help to maintain the 90-97% recycling benchmark.

According to the Copenhagen Research Institute (Present and potential future recycling of critical metals in WEEE, November 2014), increasing recycling efficiency will require more than the further development of technology solutions.

Correct collection and transport are key to these developments.

The closed-loop advantage

PV module recycling enables the recovery of various raw materials and thus helps conserve valuable natural resources. By increasing resource efficiency and decreasing waste, PV CYCLE contributes to the European Union’s environmental targets.

Analysis by the Fraunhofer Institute concluded that each recycled tonne of silicon-based PV modules can help save up to 1.2 tonnes in CO2. Especially the recycling of the aluminium and glass used in PV modules results in significant reductions of the environmental profile.

When correctly applied, PV module recycling can result in the recovery of glass, aluminium and aluminium dioxide and also copper, plastics, silicon dioxide, silver, CdTe, indium, selenide and gallium.

The recovered materials are usually used in glass packaging, glass insulation and glass foam material as well as in aluminium, copper and plastic products.

Semiconductor materials can be used as new raw materials again.

By the end of 2015, PV CYCLE’s recycling output was the equivalent of 102 million aluminium cans, 21 million clear glass bottles, 18,000 silver chains, along with many more products.

Initiatives with research institutes, dedicated taskforces and industry representatives play a pivotal role in helping to achieve the next step: higher yields, further investments in infrastructure and the establishment of industry-wide standards.

www.pvcycle.org


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