Page 97 - A Comprehensive Guide to Solar Energy Systems

92 A COMPrEHENSIVE GUIdE TO SOlAr ENErGy SySTEMS

likely that many of these will have arrived in Africa within the large quantities of WEEE
that are illegally exported from the developed world, and this quantity is likely to increase
significantly into the future. This presents both a potential problem and a potential
opportunity.
The silicon used for wafers in panels is a critical raw material which is important
for semi-conductor, aluminium alloy, silicone and silane chemical industries, as well
as for PV which accounts for 12% of global demand [27]. Manufacturing the panels is a
resource and energy intensive process, with production of Si feedstock material and
wafer manufacturing accounting for approximately two-thirds of the embodied energy
of modules [28]. Wafer production results in a loss of 40% of solar grade silicon as a slurry
when wafers are cut from silicon ingots. This slurry is notoriously problematic to recycle
[29]. recovery of wafers is therefore important from an environmental and materials
criticality point of view, with reuse of wafers in new modules reducing the carbon foot-
print by two-thirds, compared to manufacturing from virgin raw materials. When modules
reach end-of-life, many of the wafers remain functional. From an economic point of view,
wafer recovery is also important. Wafers are the most valuable component of modules, and
it is projected that by 2050, PV waste could total 78 million tonnes. The value generated by
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recovering these materials for injection back into the economy could exceed US$50 × 10
($50 billion) [30]. Inverters and other components will also become WEEE at their end-
of-life and will require appropriate management to avoid environmental impacts and to
generate economic and social value.
An economic opportunity exists for Africa if systems can be established which enable
exploitation of this inherent value in c-Si PV waste through reuse, remanufacturing and
recycling of domestically generated and imported PV waste. c-Si PV is readily recycled
around the world, with PV Cycle in Europe recently achieving record recycling efficiencies
for Si PV modules of 96% of module mass [31]. However, current design of c-Si panels
embeds wafers within ethyl-vinyl-acetate (EVA), a nonmelting plastic, which makes wafer
recovery prohibitively expensive. Consequently, the standard practice is to crush modules
to recover lower value materials rather than isolate whole wafers; this recovers <2% of a
panel’s value [32]. Processes which enable wafer isolation exist, although these are not
wide-spread and many remain at the research stage [29].
To the best of the authors’ knowledge, no PV recycling currently occurs in Africa, so end-
of-life panels would have to be exported for recycling, resulting in a missed opportunity
in terms of economic, social, and environmental value for Africa. However, many
organizations have established module assembly plants across the continent, aware of the
growing opportunities for off-grid electrification in light of the lack of grid infrastructure,
and several inverter manufacturers have also established in South Africa [4]. This, atleast,
presents opportunities to valorize modules and system components at end-of-life through
remanufacturing, given that the necessary skills, knowledge, training, and plants are now
available within the continent. It is feasible that the low labor costs, large markets for off-grid
PV systems in Africa, and the criticality of Si, might attract organizations to set up PV recycling
and remanufacturing in Africa in the future. Achieving this, however, will require significant