This document summarizes the key life cycle considerations for photovoltaic devices. It discusses how life cycle assessment examines the environmental impacts of products from raw material extraction through manufacture, use, and disposal. For photovoltaics, most impacts occur during production rather than operation. The document also compares the life cycle of silicon photovoltaics between the EU and China, finding that Chinese-made panels have over twice the carbon footprint of European panels and take 30% longer to offset their energy costs. It concludes that considering full life cycle impacts could improve prospects for domestic solar manufacturing.
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Photovoltaic Devices: Life Cycle Considerations
1. Photovoltaic Devices:
Life Cycle Considerations
Gavin D. J.
Harper
g.harper@glyndwr.ac.uk
@gavindjharper
www.gavindjharper.com
http://orcid.org/0000-0002-4691-6642
Welsh Energy Sector Training (WEST) Conference,
Liberty Stadium,
Swansea, Wales,
16th September 2014
2. What is Life Cycle Assessment?
A life cycle assessment gathers every
aspect of the products environmental
impact from the gathering of the raw
materials used to produce the
product components, all the way
through the manufacture and use of
the product to the impact the
disposal of the product has on the
environment.
4. Why is Life Cycle Assessment
Important?
• Lifecycle assessment helps us to make comparisons
between different products and services to understand
their impact on the environment over the whole of their
lifecycle.
• The results of the study provide the manufacturer and
material suppliers with information to reduce life cycle
impacts of the products.
• It also helps consumers to make informed decisions about
the relative environmental benefits of a range of different
products.
• It can inform operating, manufacturing and supply chain
decisions to move towards more sustainable options.
5. Standards for Life Cycle Assessment
• ISO 14000 series of environmental management standards.
• ISO 14040:2006 Life Cycle Assessment
• Environmental management -- Life cycle assessment -- Principles
and framework
Stage 1
Defining the goal
and scope of the
LCA
ISO 14041
Stage 2
Life cycle
inventory analysis
ISO 14042
Stage 3
Impact Analysis
ISO 14043
Stage 4
Interpretation
ISO14044
Identification of
materials, processes
and products to be
considered within
the LCA. What are
the terms of
reference.
Collect numbers on
the sources of
energy and raw
materials that are
consumed by and
the wastes that are
released from the
Translate the
numerical data on
the inputs and
outputs of the
system into real
world terms; how
does this affect the
Use the data
gained from the
LCA in order to
draw conclusions,
make
recommendations
on how
8. Lifecycle of Silicon Photovoltaics
• Quartzite rock is mined.
• Fossil fuels are used in the
processes of mining.
• The landscape is
irrevocably changed by
mining operations
Sherwani, Usmani & Varun (2010) Life
cycle assessment of solar PV based
electricity generation systems: A review,
Renewable and Sustainable Energy
Reviews, Volume 14, Issue 1, January
2010, Pages 540–544
10. Lifecycle of
Silicon Photovoltaics
• The silicon is transformed
into PV cells.
• The process will be different
depending on whether the
cells are mono c-Si or poly
c-Si.
Deutsche Gesellschaft für Sonnenenergie –
(2008) Planning and Installing Photovoltaic
Systems, Earthscan, London
11. Module Assembly
• The photovoltaic cells are
then assembled into
modules.
• Image right, Sharp
Wrexham
12. Balance of Plant
• There is also the lifecycle of all of the “balance of system”
to be considered as well.
All components of
the system have a
lifecycle impact.
13. For conventional
energy generation
technologies, the
majority of the
environmental
impact is in the
operation use or
generation phase.
For photovoltaic
cells, the bulk of the
impact occurs in the
production of the
cells.
14. End of Life (Disposal / Recovery)
• Energy and materials are consumed in the disposal of
photovoltaic devices.
• Increasingly waste is seen as a resource, rather than something
to be disposed of, there is the potential to turn this waste
stream into new products with reduced environmental impact.
• Newer PV technologies such as DSC have shorter lifecycles
due to degradation mechanisms and a lack of product
durability. Here, end of life becomes a greater consideration.
• ‘Design for disassembly’
• Building lifecycles are usually much longer than the lifecycle of
PV devices, so buildings must be planned with the anticipation
of PV replacement at some point in their lifecycle.
15. Cradle to Cradle
• Look at moving towards a
“circular” photovoltaic
economy, where panels at
the end of life become the
feedstock for new panel
production.
• Moving from “Open
System” to “Closed Loop”
recycling.
• End of life regulations are a
substantial move in this
direction.
17. End of Life Considerations for PV
• In a separate presentation, we will explore the impact of
the WEEE regulations on the End of Life considerations for
solar.
• Different photovoltaic technologies have different life
expectancies.
• Silicon photovoltaics are a durable option.
• Some technologies such as DSSC & Organic PVs currently have
shorter lifespans.
• From a construction perspective, if we are going to
integrate photovoltaic devices into buildings, we need to
consider carefully our plans for the end of the
photovoltaic cells useful life.
18. How long do PV’s last?
• Insufficient data to be
truly certain.
• Photovoltaic
Degradation Rates —
An Analytical Review
NREL is a good study.
3.5
3
2.5
2
1.5
1
0.5
0
Amorphous silicon (a-
Si)
Cadmium telluride
(CdTe)
Copper indium gallium
selenide (CIGS)
Monocrystalline silicon
(mono-Si)
Polycrystalline silicon
(poly-Si)
PV Output Loss % per Year (NREL)
Output loss in percent per year Pre 2000 Output loss in percent per year Post 2000
19. PV Warranties
• The adjacent graph,
from
http://energyinformative.org/lifespan-solar-panels/
shows the warranties
offered by some PV
manufacturers.
• A warranty considered
standard by many in the
industry is the
performance of the PVs
should be no less than
80% of rated power after
25 years
20. Anecdotal Reports of PV Life
• There are a number of anecdotal reports that give
encouraging signs about silicon PV lifespans.
• An Arco Solar 16-2000 33W outperformed it’s factory spec
30 years after it was manufactured.
• The first “modern” solar panel still works after 60 years.
• Kyocera reports a number of solar power installations that
continue to operate reliably and generate electricity.
These installations are all nearly 30 years old.
21. Financial Lifespan vs. Actual
• We tend to consider “20 years” as the lifespan of a PV
installation when calculating the financial returns.
• However, the actual in-service life, in many cases would
seem to exceed the performance used for financial
calculations.
22. That said…
• More regular replacement required of other
components.
• For off-grid, or grid storage systems, batteries
typically require replacement every five years or
so.
• Inverters and power electronics wear out, and
may also require replacement every 5-10 years.
23. Cultures of Construction
United States – Shingle Roof
Replaced every 25 years
United Kingdom – Slate Roof
Replaced every 100+ years
24. Cultures of Construction
• Building Integrated Photovoltaic Devices may require
changes of culture within the construction industry.
• “Bolt on” photovoltaics can be removed relatively easily.
• Truly “Building Integrated” PV devices may require structured
planning for End-of-Life and replacement considerations.
• If we consider the lifecycle of photovoltaics is relatively
short in comparison with the lifetime of the building; then
we can anticipate that within a building lifecycle, there
may need to be several replacements of photovoltaic
devices.
26. Lifecycle Analyses in the Literature
• Over the past thirty years a great deal of
data has been gained on the Lifecycle
impacts of PV systems.
• There are hundreds of different LCAs
available in the academic literature on a
range of different types of system and
technology.
• There are wide variations in the outcomes of
LCA evaluations of PV technologies.
27. Variations in the Literature
• Variation could be attributed to
• differences in technologies evaluated
• differing system designs
• commercial versus conceptual systems,
• system operating assumptions,
• technology improvements over time
• LCA methods and assumptions
NREL (2012)
NREL/FS-6A20-56487
• Meta analysis “aggregates” these different
examples from the literature into a more coherent
picture.
28. Comparison of as-published
life cycle
greenhouse gas
emission estimates for
electricity generation
technologies. The
impacts of the land use
change are excluded
from this analysis.
Credit: Sathaye, J., O. Lucon, A. Rahman, J. Christensen,
F. Denton, J. Fujino, G. Heath, S. Kadner, M. Mirza, H.
Rudnick, A. Schlaepfer, A. Shmakin, 2011: Renewable
Energy in the Context of Sustainable Energy. In IPCC
Special Report on Renewable Energy Sources and
Climate Change Mitigation [O. Edenhofer, R. Pichs-
Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S.
Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer,
C. von Stechow (eds)], Cambridge University Press.
Figure 9.8
http://www.nrel.gov/analysis/sustain_lca_results.
29. From:
MacKay (2008)
LCA: PV’s in Use
• Land use an important
consideration “in Use”
• (Hence the need to
make good use of
roof spaces with
BIPV).
30. Why is Life Cycle Assessment
relevant to the Welsh Solar
Industry
• Trade wars between EU / China
• China can manufacture Photovoltaic devices more
cheaply.
• BUT Heavily reliant on dirty forms of energy.
• Poor environmental controls compared to EU Solar Industry.
• Need to question ourselves and our motives…
• Why are we actually pushing for photovoltaics devices.
• Cleaner, more responsible energy future.
• Potential for Welsh Solar industry to regain competitive
advantage if life cycle impacts of PV installations rise up
the political agenda.
31. Life Cycle Assessment: EU vs. China
• Yue, You & Darling (2014) identify that most pre-existing
literature on Solar PV LCA focused on the US / EU.
• This contrasts with most PV manufacturing which is
outsourced to non-OECD countries.
• These countries have radically different conceptualisations
of industrialisation and environmental protection.
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
32. Life Cycle Assessment: EU vs. China
• Their lifecycle analysis focuses on Crystalline Silicon
technologies: looking at mono c-Si, poly c-Si and
ribbon c-Si.
• Thin film cells not considered in this analysis.
• Challenges as there are gaps within the literature.
• c-Si cell manufacture has become “commoditised” using
standard processes and equipment, by contrast thin film cell
manufacture is more “proprietary”.
• Organic cells similarly in their infancy, so lack of data.
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
33. Life Cycle Assessment: EU vs. China
•The factors evaluated include:
• Energy Payback
• Energy Return on Investment
• Greenhouse Gas Emissions
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
34. Life Cycle Assessment: EU vs. China
Cumulative Energy Demand
(Lower is better)
CN = China, RER =
Europe
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
35. Life Cycle Assessment: EU vs. China
Energy Payback Time
(Lower is better)
CN = China, RER =
Europe
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
36. Life Cycle Assessment: EU vs. China
Energy Return on Energy
Invested
(Higher is better)
CN = China, RER =
Europe
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
37. Life Cycle Assessment: EU vs. China
Carbon Footprints
(Lower is better)
CN = China, RER =
Europe
Dajun Yue, Fengqi You, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
38. Yue, You & Darling (2014) Conclusions
• Mainstream Chinese-made silicon solar panels have more
than twice the carbon footprint than panels made in
Europe
• Mainstream Chinese-made silicon solar panels take up to
30 percent longer to offset the energy used to make them
• Their analysis doesn't include transportation costs to get
them to Europe, which would magnify the discrepancy
even more.
39. Yue, You & Darling (2014) Conclusions
• Monocrystalline was found to have the longest energy
payback period despite the best energy output.
• Analysis comparing mono-Si and multi-Si technologies
suggest that these do not significantly differ in life cycle
GHG emissions
• “Ribbon" silicon, stringing out the material from a molten
bath, created the least efficient material but did so more
efficiently and with faster energy payback.
40. Life Cycle Assessment: EU vs. China
• Yue, You & Darling (2014) present a ‘break even
carbon tariff’ on imported photovoltaic devices.
• This would equate to €105–€129/ton CO2
• This would offset environmental burden of
imported PV.
• Could improve fortunes of domestic
DamjuannYuuefa, Fcentugqrei Yrso?u, Seth B. Darling, (2014) “Domestic and overseas
manufacturing scenarios of silicon-based photovoltaics: Life cycle
energy and environmental comparative analysis” Solar Energy, Volume
105, July 2014, Pages 669–678
41. Wales: Could Welsh manufacturing
compete on lower environmental
impact?
"The fact is, we cannot any longer ignore things like carbon
footprinting -- especially in the energy space, where we
should be the people most aware of the issue,"
"Today it's essentially being ignored."
Seth Darling, Scientist
U.S. Department of Energy's Argonne National Laboratory
43. Sharp Closure
• Whilst Sharp has closed, it is
interesting to consider it’s
activities through the lens of
Yue, You & Darling (2014).
Photo by Peter Byrne/WPA Pool/Getty Images
44. Sharp Manufacturing,
Sharp ClosureLlay, Wrexham
Crystalline
Silicon Cells
Brought From
Taiwan To Llay
Finished
modules
shipped back
to Japan.
45. Where is the impact in
“Welsh Assembled” Modules
The bulk of the energy and carbon impact occurs in the
manufacture of the silicon feedstock, crystals, wafers
aMnodd culeel lsa.ssembly represents a relatively small proportion
of the overall environmental impact.
46. How to assign value to sustainable
solar manufacturing
• Suggestion for the future – not currently on the agenda.
• Challenges in tariffs based on location of manufacture.
• How to allocate if cell manufacture and module manufacture
carried out in different places.
• How to equitably allocate tariffs across the supply chain.
• Look at the food industry for possible pitfalls
• Product labelling based on last point food was handled /
processed / packaged. (Horsemeat scandal arose from poor
knowledge of product origin).
• Need for PV carbon “chain of custody”?
• Don’t want product labelling based on “last point of
contact” as it distorts perception of (environmental)
quality & impact.
47. Opportunities for the
Welsh Solar Industry
• Were the regulatory environment to shift to recognise the
environmental impacts of PV manufacturing, there could
be more opportunities for the ‘Western’ PV manufacturers.
• At present STA has fought against “Anti-Dumping” tariffs,
and import restrictions as the jobs in “installation”
outweight the jobs in “manufacture”.
• The UK is currently most vibrant market for PV in the EU, and no
appetite to starve that growth.
• BUT, could we do things cleaner, greener, better with
appropriate incentives and what opportunities would that
present for UK industry?
50. If you found any of this interesting…
Please stay in touch
Gavin Harper
g.harper@glyndwr.ac.uk
www.gavindharper.com
http://www.cser.org.uk/
@gavindjharper
@CSER_PV
@LCRI_WEST
https://www.westproject.org.uk/