6. Economic aspects

5. Environmental aspects

Organic solvent dissolution

20 Solar Panels and Photovoltaic Materials

Mechanical separation by hotwire cutting

Dry and wet mechanical process

Several studies have analyzed the impacts of recycling processes for PV modules on the environment. There are advantages and disadvantages of the different methods, considering all the stages, from the collection of the PV modules to the end of the recycling process.

Process Advantages Disadvantages Status Ref.

• Time for delamination depends on area • Harmful emissions and wastes

• Very expensive equipment

• Other separation processes required for encapsulant

• Further chemical or mechanical treatments needed

• High losses of valuables during rinsing and sieving process • Flotation process required

• High effort for purification

• Harmful emissions • High energy requirements • Cell defects and degradation

• High use of chemicals • Generation of acidic fumes • Complex control of chemicals

required for encapsulant • Dusts containing heavy metals • Breakage of solar cells • Equipment corrosion

• No removal of dissolved solids Commercial [56]

• Use of chemicals Commercial [58–60]

• Relatively slow process • Emission of metals • Further chemical/mechanical

treatments

• Slow process

Research [62]

Research [63]

Research [52]

[55]

[55]

[55]

Research (pilot)

Research (pilot)

Research (pilot)

Commercial [43]

Commercial [55]

Commercial [55]

Commercial [64]

• Easy access to the encapsulant • Less cell damage • Recovery of glass

encapsulant

• Low cell damage • Recovery of glass

layers without chemicals • Recovery of clean glass

Dry etching • Simple process • High energy demand

Physical disintegration • Capable of treating waste • Other separation processes

• Recovery of clean glass

• Low use of chemicals

• No process chemicals • Equipment widely available • Low energy requirements

• Simple and efficient process

encapsulant • Recovery of intact cell • Simple and economical

metals

Irradiation by laser • Easy access to the

Vacuum blasting • Removal of semiconductor

Attrition • No usage of chemicals

Flotation • Relatively simple process

Chemical etching • High purity materials

Leaching • Complete removal of

Table 2. Thin-film solar modules recycling processes.

Thermal treatment • Full removal of

The recovery of valuable materials during the recycling of PV modules can have great economical value. The extraction of secondary raw material from EoL PV modules, if made in an efficient way, can make them available to the market again [68].

Attention has been paid particularly to silver. PV modules that reach their EoL will build up a large stock of embodied raw materials (as mentioned previously), which can be recovered and become available for other uses or even for solar cells again. However, this will not occur before 2025, according to some forecasts [68].

The ITRPV predicts that, by 2030, the total material value recovered from PV recycling can reach USD 450 million. With this amount it is possible to produce 60 million PV modules (18 GW), which would be approximately 33% of the 2015 production [7]. Considering Si, up to 30,000 t of silicon can theoretically be recovered in 2030 [7], which is the amount of silicon needed to produce approximately 45 million new modules. Considering a polysilicon current prices at USD 20/kg and a recovery rate from commercial recycling processes of 70% this is equivalent to USD 380 million [7].
