ENVIRONMENTAL BENEFITS OF SILICON KERF SECONDARY PRODUCTS IN PILOT PROCESSES
OVER CONVENTIONAL PRODUCTION OF EQUIVALENT PRODUCTS WITH PRIMARY RAW
MATERIALS IN CHINA AND EUROPE
René Peche, Ma hias Sei z, Ma kus Schönhei s, Ka s en Wambach
bi a Umwel ins i u GmbH
Am Mi le en Moos 46, 86167 Augsbu g, Ge many
ABSTRACT: bi a Umwel ins i u GmbH is e alua ing ou pilo uni s newly de eloped in he ICARUS p ojec o
p ocessing silicon ke was e in o seconda y ma e ials and ma ke able p oduc s and shows whe he an ecological
imp o emen compa ed o he con en ional Chinese and Eu opean supply o unc ionally equi alen ma e ials om
p ima y aw ma e ial can be achie ed. The e alua ion is done using he me hod o li e cycle assessmen (LCA). The
u ning o PV was e silicon ke in o seconda y aw ma e ials o ma ke able p oduc s elimina es a la ge pa o he
en i onmen al impac associa ed wi h he con en ional p oduc ion o equi alen aw ma e ials o p oduc s. The
educ ion in en i onmen al impac anges om mo e han 85% o he p oduc ion o seconda y me allu gical g ade and
sola g ade silicon compa ed o he con en ional p oduc ion in China o e mo e han 75% o he p oduc ion o
seconda y me allu gical g ade and sola g ade silicon compa ed o he con en ional p oduc ion in Eu ope o mo e han
30% o he p oduc ion o hyd ogen and wa e glass om silicon ke was e compa ed o he con en ional p oduc ion
in Eu ope. Thus, he newly de eloped p ocesses in he ICARUS p ojec no only educe dependence on supplies om
Asia, bu also help o educe ha m ul emissions in o he en i onmen du ing he p oduc ion o aw ma e ials.
Keywo ds: LCA; ecology index; seconda y ma e ials; silicon; ecycling; PV modules
1 INTRODUCTION
In he ICARUS p ojec , 17 Eu opean pa ne s a e
collabo a ing o de elop inno a i e me hods o
p ocessing and e ining seconda y aw ma e ials om
silicon PV manu ac u ing. This in ol es ans o ming he
p ocess was es Si-ke was e, g aphi e was e and silica
was e om silicon (Si)ingo and wa e p oduc ion in o
aluable seconda y esou ces (Figu e 1).
Figu e 1: ICARUS p ojec
Fo il e ed Si-Ke , which is p oduced du ing he diamond
wi e sawing o silicon blocks in o wa e s, ou pilo
p ocesses ha e been de eloped and ope a ed,
demons a ing he ele ance o he di e en echnological
op ions and b inging modula i y in: (a) Si-ke ecycling
and e ining (PILOT A, B and C) conside ing di e en
inpu s and pu i y g ades o di e se applica ions; and (b)
e alo isa ion o Si (PILOT D), ans o ming Si-ke in o
he aluable commodi ies g een hyd ogen and wa e glass.
The ene gy in ensi y o silicon is s ongly ela ed o i s
pu i y. The e o e, he ICARUS p ojec will ake ad an age
o he silicon con en o he ke , in es ed wi h a lo o
ene gy, and euse i as seconda y aw ma e ial. Fo
example, eusing seconda y silicon in wa e p oduc ion
can signi ican ly educe he high ene gy demands
associa ed wi h p ocessing p ima y aw Si in o wa e s,
which accoun s o abou 75 % o he o al ene gy used in
PV module manu ac u ing.
The LCA conduc ed in he ICARUS p ojec suppo s and
quan i ies he p ocess de elopmen s.
2 METHOD
An LCA is a sys em analysis me hod o he
in eg a ed, media-wide acquisi ion and e alua ion o
en i onmen - ela ed ma e s in connec ion wi h p oduc s,
p ocesses and se ices. LCA a e cha ac e ized by he
analyses o en i onmen al in luences in associa ion wi h
p io o subsequen li e cycle s ages. Also conside ed he e
a e inpu s and wi hd awals o aw ma e ials and ene gy o
and om en i onmen al media, namely wa e , ai and
ea h. O e all, LCA can make a comp ehensi e s a emen
on he ele ance o he en i onmen o he sys ems
in es iga ed and a e he e o e op imally sui ed o
en i onmen - ela ed compa ison o a ious sys ems.
The LCA in he ICARUS p ojec is ca ied ou unde
he no m speci ica ions o he execu ion o eco-balances
DIN EN ISO 14040 [1] and DIN EN ISO 14044 [2], aken
in o accoun he P oduc En i onmen al Foo p in
Ca ego y Rules (PEFCR) o pho o ol aic modules used
in pho o ol aic powe sys ems o elec ici y gene a ion
[3,4]. S a ing wi h he de ini ion o goal and scope unde
he e ms o he Li e cycle in en o y analysis, all ele an
pa ame e s a e eco ded and summa ized in he li e cycle
impac assessmen ega ding hei en i onmen al impac .
Figu e 2 shows a schema ic o e iew o he basic
compila ion o an LCA wi h ields o applica ion.
Figu e 2: Schema ic o e iew o he basic compila ion
o an LCA wi h ields o applica ion
Table 1 shows he hi een impac ca ego ies ha a e
assessed and in e p e ed in he LCA o he ICARUS
p ojec .
.
Table 1: Applied en i onmen al impac ca ego y used in
he ICARUS p ojec
Impac ca ego y Uni
Clima e change kg CO2 eq.
Ozon deple ion kg CF-11 eq.
Pa icula e ma e Disease Incidence
Ionizing adia ion, human
heal h
kBq U235 eq.
Pho ochemical ozone
o ma ion, human heal h
kg NMVOC eq.
Acidi ica ion mole H+ eq.
Eu ophica ion, e es ial mole N eq.
Eu ophica ion, eshwa e kg P eq.
Eu ophica ion, ma ine kg N eq.
Land use P
Wa e use kg wo ld eq. dep i ed
Resou ce use, mine als and
me als
kg Sb eq.
Resou ce use, ene gy
ca ie s
MJ
The indi idual esul s o he impac ca ego ies a e
combined using he no maliza ion and weigh ing ac o s
published by he Eu opean Commission’s Join Resea ch
Cen e [5,6], o c ea e a dimensionless single ecological
indica o – he so-called ecology index.
3 RESULTS
In o ma ion and p ocess da a o he pilo p ocesses
a e p o ided by he p ojec pa ne s. The Chinese and
Eu opean p oduc ion p ocesses a e modelled using da a
om IEA PVPS Task 12 [6] and ecoin en da abase [7].
The da a se s used oge he wi h he p ocess da a and
in o ma ion o c ea e he LCA models also came om he
ecoin en da abase.
PILOT A p ocess: Seconda y d y silicon compa ed o
con en ional me allu gical g ade silicon p oduced in
China and Eu ope
The p oduc o he pilo A p ocess de eloped by
p ojec pa ne Resi ec AS (No way) is seconda y d y
silicon wi h less han 1% mois u e. The s a ing ma e ial is
il e ed Si-ke con aining 47 % mois u e om he silicon
wa e sawing p ocess.
The compa able con en ional p oduc is me allu gical
g ade silicon, p oduced om p ima y silica sand.
Figu e 3: Compa ison o he ecological indices o he
pilo A p ocess and he con en ional p oduc ion
p ocesses in China and Eu ope
Figu e 3 demons a es ha seconda y d y silicon has
an ecological ad an age o mo e han 90 % o e
con en ional p oduc ion o me allu gical g ade silicon in
China, and almos 80% compa ed o con en ional
p oduc ion in Eu ope
The imp o ed ecology index can be a ibu ed
p ima ily o he lowe quan i y o ene gy used in he pilo
A p ocess, and seconda ily o he use o ma e ials, which
is signi ican ly educed compa ed o hose used in he
Chinese and Eu opean p oduc ion p ocesses.
Fo ins ance, he elec ici y consump ion o he pilo
A p ocess is mo e han eigh imes lowe han ha equi ed
o he con en ional p oduc ion o me allu gical g ade
silicon. Fu he mo e, unlike he 2 con en ional p oduc ion
p ocesses he pilo A p ocess does no equi e any he mal
ene gy
PILOT B and PILOT C p ocesses: Seconda y silicon
6N+ and 8N compa ed o con en ional sola g ade
silicon p oduced in China and Eu ope
The p oduc o he pilo B p ocess de eloped by
p ojec pa ne ROSI SAS (F ance) is seconda y silicon o
8N pu i y and he p oduc o he pilo C p ocess de eloped
by p ojec pa ne No he n Silicon (No way) is seconda y
silicon o 6N+ pu i y.
The compa able con en ional p oduc is sola g ade
silicon, p oduced om p ima y me allu gical g ade
silicon.
Figu e 4: Compa ison o he ecological indices o he
pilo B and pilo C p ocesses and he con en ional
p oduc ion p ocesses in China and Eu ope
Figu e 4 shows ha he seconda y silicon 8N and 6N+
ha e an ecological ad an age o mo e han 85 % o e he
con en ional p oduc ion o sola g ade silicon in China
and mo e han 75% o e he con en ional p oduc ion in
Eu ope.
The imp o ed ecological indices a e due o he same
ac o s as desc ibed o pilo A p ocess. The main eason
is he lowe quan i y o ene gy used in he pilo p ocesses.
In addi ion, he consump ion o p ima y ma e ials is
signi ican ly lowe compa ed o he con en ional
p oduc ion p ocesses because o he use o was e as a
s a ing ma e ial.
PILOT D p ocess: Hyd ogen and wa e glass p oduced
om silicon ke compa ed o con en ional hyd ogen
and sodium silica e p oduced in Eu ope
The p oduc s o he pilo D p ocess de eloped by
p ojec pa ne LuxChem ech GmbH (Ge many) a e
hyd ogen and wa e glass. The s a ing ma e ial is he
p ocessed Si-ke om he pilo A p ocess.
In he con en ional p oduc ion p ocesses o hyd ogen
(p oduced ia he c acking o ossil uels and chlo -alkali
elec olysis) and wa e glass (p oduced om he u nace
p ocess), he s a ing ma e ials a e na u al gas and he
silica sand as well as soda ash, espec i ely.
Figu e 5: Compa ison o he ecological indices o he
pilo D p ocess and he con en ional p oduc ion
p ocesses in Eu ope
Figu e 5 shows ha hyd ogen and wa e glass
p oduced om silicon ke ha e an ecological ad an age
o mo e han 30 % o e he con en ional p oduc ion o he
wo p oduc s in Eu ope.
The imp o ed ecology index esul s om he
educ ion o p ima y aw ma e ials and he lowe
consump ion o ossil uels, which a e ypically equi ed
o con en ional hyd ogen and wa e glass p oduc ion.
4 DISCUSSION AND CONCLUSION
The u ning o PV was e silicon ke , which is ene gy-
dense and ich in highly pu e silicon, in o seconda y aw
ma e ials o ma ke able p oduc s elimina es a la ge pa o
he en i onmen al impac associa ed wi h he con en ional
p oduc ion o equi alen aw ma e ials o p oduc s.
The educ ion in en i onmen al impac anges om
mo e han 85% o he p oduc ion o seconda y
me allu gical g ade and sola g ade silicon compa ed o
he con en ional p oduc ion in China o e mo e han 75%
o he p oduc ion o seconda y me allu gical g ade and
sola g ade silicon compa ed o he con en ional
p oduc ion in Eu ope o mo e han 30% o he p oduc ion
o hyd ogen and wa e glass om silicon ke was e
compa ed o he con en ional p oduc ion in Eu ope.
Thus, he newly de eloped p ocesses in he ICARUS
p ojec no only educe dependence on supplies om Asia,
bu also help o educe ha m ul emissions in o he
en i onmen du ing he p oduc ion o aw ma e ials.
5 REFERENCES
[1] DIN EN ISO 14040:2021-02: En i onmen al
managemen - Li e cycle assessmen - P inciples and
amewo k (ISO 14040:2006 + Amd 1:2020),
Deu sches Ins i u ü No mung DIN e.V.; 2021
[2] DIN EN ISO 14044:2021-02: En i onmen al
managemen - Li e cycle assessmen - Requi emen s
and guidelines (ISO 14044:2006 + Amd 1:2017 +
Amd 2:2020), Deu sches Ins i u ü No mung DIN
e.V.; 2021
[3] P oduc En i onmen al Foo p in Ca ego y Rules
(PEFCR) o pho o ol aic modules used in
pho o ol aic powe sys ems o elec ici y gene a ion.
Eu opean Commission’s Join Resea ch Cen e -
Ins i u e o En i onmen and Sus ainabili y; 2020
[4] JRC Technical Repo - Upda ed cha ac e isa ion and
no malisa ion ac o s o he En i onmen al Foo p in
3.1 me hod. Eu opean Commission’s Join Resea ch
Cen e - Ins i u e o En i onmen and Sus ainabili y;
2023
[5] JRC Technical Repo s - De elopmen o a weigh ing
app oach o he En i onmen al Foo p in . Eu opean
Commission’s Join Resea ch Cen e - Ins i u e o
En i onmen and Sus ainabili y; 2018
[6] Li e Cycle In en o y and Li e Cycle Assessmen s o
Pho o ol aic Sys ems. Repo IEA-PVPS T12-
19:2020, In e na ional Ene gy Agency; 2020
[7] Li e cycle in en o y da abase ecoin en 3.8:
h ps://www.ecoin en .o g, Zü ich; 2021
6 ACKNOWLEDGEMENTS
This wo k has ecei ed unding om he Eu opean
Union’s Ho izon 2020 esea ch and inno a ion
p og amme unde g an ag eemen No 958365; p ojec
ICARUS.
Views and opinions exp essed a e howe e hose o
he au ho s only and do no necessa ily e lec hose o he
Eu opean Union o CINEA. Nei he he Eu opean Union
no he g an ing au ho i y can be held esponsible o
hem.
