Renewable and Sustainable Energy Reviews xxx (xxxx) xxx
Please cite this article as: Preeti Nain, Arun Kumar, Renewable and Sustainable Energy Reviews, https://doi.org/10.1016/j.rser.2019.109592
1364-0321/© 2019 Elsevier Ltd. All rights reserved.
Initial metal contents and leaching rate constants of metals leached from
end-of-life solar photovoltaic waste: An integrative literature review
and analysis
Preeti Nain, Arun Kumar
*
Department of Civil Engineering, Indian Institute of Technology, New Delhi, India
A R T I C L E INFO
Keywords:
Solar photovoltaic waste
Carcinogenic metals
Initial metal content
Leachate rate constants
End-of-life
ABSTRACT
The photovoltaic (PV) technology is one of the fastest growing renewable and environmental friendly sources of
electricity. However, this huge deployment rate is associated with generation of end-of-life (EoL) PV waste
containing particularly, carcinogenic metals, once their operation phase ends. This study attempted to address
this upcoming waste issue by systematically reviewing about 300 review/theoretical/case/research papers/
books/patents published between 2000 and 2018. The information was compiled and synthesized on: (i) initial
metal concentration/content (IMC) for silicon-PV, amorphous-PV, CIGS and CdTe PVs; ii) statistical character-
isation and distribution of compiled IMCs; iii) leached metal concentrations (mg/l) from various PVs in water-
based leaching solutions, as per standard waste characterisation methods, in acid leaching and landfll matrix;
iv) metal leaching rate constants (LRC) by ftting exponential model on reported plots of leached metal con-
centration values versus time using the GetData software; v) feasible application of compiled IMC and LRC data
for: a) Leachate Pollution Index (LPI) determination of an MSW landfll dumped with solar-PV waste, b) human
health risk assessment (HHRA) for exposure to lead leached from solar PV waste in an MSW landfll; vi) data/
knowledge gaps from literature review and highlight the required future research actions.
The range of IMC values for top three solar PV-associated carcinogens, arsenic, cadmium and lead (% weight)
were obtained to be: 0.00–0.001, 0.0001–19.84, and 0.003–5.09, respectively. Further, the range of LRC of solar
PV-associated leached arsenic, cadmium and lead were obtained to be (per day): 0.00–0.129, 0.001–0.031, and
0.003–0.041, respectively. Leaching of Cd, Pb and Se from PVs have been mostly studied in acidic conditions (pH
3.0–6.5), whereas, fate of solar PVs in landfll conditions was not observed to be studied much. The estimation of
contribution of solar PV in leachate pollution potential of an existing MSW landfll at T
90
values (i.e., time
required for 90% leaching of metals) showed an increase of 5.15% in pollution potential of landfll if landfll
were to be dumped with EoL PV waste as well. HHRA for exposure to groundwater contaminated with leachate
from a landfll dumped with lead containing solar PV waste did not pose any signifcant risk, however, the
carcinogenic effects due to other metals under this scenario cannot be neglected. Out of 85 studies selected for
content analysis, only 2.39% of them investigated the fate of PVs in landfll stimulating conditions. To address
the fate of EoL solar waste and reduce uncertainty in present work, following future research actions need to be
initiated: (i) conduct experimental studies to obtain data on metal leaching under realistic dumping scenarios
and landfll conditions (intact solar panels with bigger size in MSW landfll); (ii) revise the expression of LPI for
including solar PV-based LPI with critical parameters, like carcinogenic metals (cadmium); (iii) investigate
suitability of existing standard hazardous waste characterizing methods (TCLP or WET) for PV waste.
1. Introduction
Solar PV has shown exponential growth with most promising alter-
native to fossil fuel [1]. PV technologies are based on different types of
materials used, effciency and size. The main PV technologies available
in the market on the basis of maturity, are: i) frst-generation crystal-
line-Si, representing 90% of the PV market (40% mono-, 48% multi-, and
2% ribbon Si); ii) second-generation thin-flm technologies, covers the
remaining 9% of the market share (5% CdTe (cadmium telluride), 2%
* Corresponding author.
E-mail address: arunku@civil.iitd.ac.in (A. Kumar).
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Renewable and Sustainable Energy Reviews
journal homepage: http://www.elsevier.com/locate/rser
https://doi.org/10.1016/j.rser.2019.109592
Received 25 March 2019; Received in revised form 7 October 2019; Accepted 12 November 2019