IEC TS 62994:2019

Photovoltaic (PV) modules through the life cycle - Environmental health and safety (EH&S) risk assessment - General principles and nomenclature

IEC 62994:2019 specifies definitions of terms and introduces evaluation methods for EH&S risk assessment for the PV module over the product life cycle. Environmental health and safety (EH&S) risk assessment is a method to characterize and evaluate potential adverse impacts to human health or environment and make it possible to take measures to reduce them. EH&S risk assessment of PV modules is very important for the safe and sustainable manufacture, use, and end of life treatment of PV modules. The definition of terms can be applied to the EH&S risk assessment through the life cycle of PV modules. Generally, evaluation methods for the EH&S risk assessment can be divided in two cases:
- ordinary foreseen routine operation, in which life cycle assessment method is applied;
- abnormal non-routine operation, in which risk assessment method is applied

General Information

• Status: Published
• Publication Date: 28-Jan-2019
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: PT 62994-1 - TC 82/PT 62994-1
• Current Stage: PPUB - Publication issued
• Start Date: 29-Jan-2019
• Completion Date: 31-Jan-2019

Overview

IEC TS 62994:2019 - Photovoltaic (PV) modules through the life cycle: Environmental health and safety (EH&S) risk assessment - General principles and nomenclature - provides standardized definitions and evaluation methods for assessing EH&S risks associated with PV modules over their entire product life cycle. The Technical Specification frames EH&S risk assessment as a tool to characterize and evaluate potential adverse impacts to human health and the environment and to guide mitigation during manufacture, use and end‑of‑life (EOL) treatment.

Key Topics

• Definitions and nomenclature for EH&S risk assessment specific to PV modules, aligned with IEC/ISO terminology.
• Life Cycle Assessment (LCA) for routine, foreseen operations:
  • LCA fundamentals and application to PV electricity production.
  • Photovoltaics‑specific considerations (module materials, manufacturing, use phase).
  • Life cycle inventory modelling, Life Cycle Impact Assessment (LCIA), interpretation and reporting.
• Environmental and Health Risk Assessment (EHRA) for abnormal, non‑routine operations:
  • EHRA principles, process steps and integration with risk management.
  • Assessment scope limited to the PV module, supply chain, operation, EOL treatment and direct interfaces with balance-of-system components.
• EH&S management system guidance:
  • Policy, planning, implementation, checking, management review and end‑of‑life management.
• Supporting resources: informative annexes listing LCA and EHRA sources relevant to PV.

Practical Applications

• Use IEC TS 62994:2019 to develop consistent, auditable EH&S assessments for PV modules across the product life cycle.
• Apply LCA procedures defined by the TS to quantify routine environmental impacts (manufacturing, use, disposal/recycling) and to calculate metrics such as energy payback or impact categories.
• Use EHRA guidance to evaluate and mitigate risks from non‑routine events (accidental release, abnormal exposure, hazardous material handling).
• Support internal EH&S management, supplier audits, product stewardship, sustainability reporting, and EOL planning (recycling/repurposing).

Who Should Use This Standard

• PV module manufacturers and R&D teams
• Environmental, health & safety (EH&S) managers and sustainability officers
• Lifecycle assessment practitioners and consultants working on solar PV
• Policy makers, recyclers and EOL service providers
• Certification bodies and auditors evaluating PV product safety and environmental performance

Related Standards

• ISO 14040 / ISO 14044 (LCA principles and requirements)
• ISO 14001 / ISO 14004 (Environmental management systems)
• IEC TS 61836 (PV terms and definitions)
• IEC 61724‑1 (PV system performance monitoring)
• ISO/IEC Guide 51 and OHSAS 18001 (safety and H&S management guidance)

IEC TS 62994:2019 helps standardize EH&S risk assessment language and workflows for PV modules, enabling safer manufacturing, informed risk management, and more sustainable end‑of‑life strategies for photovoltaic products.

Standards Content (Sample)

IEC TS 62994 ®
Edition 1.0 2019-01
TECHNICAL
SPECIFICATION
colour
inside
Photovoltaic (PV) modules through the life cycle – Environmental health and
safety (EH&S) risk assessment – General principles and nomenclature
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IEC TS 62994 ®
Edition 1.0 2019-01
TECHNICAL
SPECIFICATION
colour
inside
Photovoltaic (PV) modules through the life cycle – Environmental health and

safety (EH&S) risk assessment – General principles and nomenclature

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-6419-5

– 2 – IEC TS 62994:2019 © IEC 2019
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 7
3 Terms and definitions . 8
4 Basic principles of EH&S risk assessment for the PV module . 9
4.1 Basic concepts . 9
4.2 Life cycle assessment (LCA) of PV . 10
4.2.1 Fundamentals . 10
4.2.2 Photovoltaics-specific aspects . 11
4.2.3 Life cycle inventory modelling aspects . 12
4.2.4 Life cycle impact assessment (LCIA) . 16
4.2.5 Interpretation . 18
4.2.6 Reporting and communication . 19
4.3 Environmental and Health Risk Assessment (EHRA) of PV module . 20
4.3.1 Principle . 20
4.3.2 Process . 21
4.3.3 Risk assessment and risk management . 24
4.3.4 Risk assessment of PV related equipment . 24
4.4 EH&S management system . 25
4.4.1 General . 25
4.4.2 EH&S Policy . 26
4.4.3 Planning . 26
4.4.4 Implementation and operation . 27
4.4.5 Checking . 27
4.4.6 Management review . 27
4.4.7 End of life management . 28
Annex A (informative) Sources for LCA and EHRA for PV . 29
A.1 Sources for LCA of PV . 29
A.2 Sources for EHRA for PV . 29
Bibliography . 30

Figure 1 – Product system of electricity produced with photovoltaic modules . 7
Figure 2 – Contribution of risk assessment to the risk management process . 24
Figure 3 – Environmental management system model . 25

Table 1 – Impact categories and indicators . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC (PV) MODULES THROUGH THE LIFE CYCLE –
ENVIRONMENTAL HEALTH AND SAFETY (EH&S) RISK ASSESSMENT –

General principles and nomenclature

FOREWORD
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Technical specifications are subject to review within three years of publication to decide
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IEC TS 62994, which is a technical specification, has been prepared by IEC technical
committee 82: Solar photovoltaic energy systems.

– 4 – IEC TS 62994:2019 © IEC 2019
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
82/1370/DTS 82/1504/RVDTS
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INTRODUCTION
This Technical Specification establishes definitions of terms of environmental health and
safety (EH&S) risk assessment and also basic principles and general methods for the EH&S
risk assessment for the PV module through its life cycle.
EH&S risk assessment is a method to characterize and evaluate potential adverse impacts to
human health or environment in order to develop policies to control and reduce them.
Although PV technologies have environmental advantages over conventional energy
technologies, PV modules can contain some hazardous materials. Therefore, EH&S risk
assessment of PV modules is very important for the safe and sustainable manufacture, use,
and end-of-life treatment of PV modules.
Though there are many standards relating to EH&S and risk assessment, there is no
published IEC standard for the EH&S risk assessment of the PV module at present.
This technical specification was developed in cooperation with IEA PVPS task 12
(PV Environmental, Health and Safety Activities). The objectives of the task are to ‘quantify
the environmental profile of PV in comparison to other energy technologies’ and ‘to define and
address EH&S and sustainability issues that are important for PV market growth’. IEA PVPS
task 12 and IEC TS 62994 Project team had joint meetings and established a liaison officer to
work on this technical specification on the EH&S for the PV.

– 6 – IEC TS 62994:2019 © IEC 2019
PHOTOVOLTAIC (PV) MODULES THROUGH THE LIFE CYCLE –
ENVIRONMENTAL HEALTH AND SAFETY (EH&S) RISK ASSESSMENT –

General principles and nomenclature

1 Scope
This document specifies definitions of terms and introduces evaluation methods for EH&S risk
assessment for the PV module over the product life cycle. Environmental health and safety
(EH&S) risk assessment is a method to characterize and evaluate potential adverse impacts
to human health or environment and make it possible to take measures to reduce them. EH&S
risk assessment of PV modules is very important for the safe and sustainable manufacture,
use, and end of life treatment of PV modules. The definition of terms can be applied to the
EH&S risk assessment through the life cycle of PV modules. Generally, evaluation methods
for the EH&S risk assessment can be divided in two cases:
• ordinary foreseen routine operation, in which life cycle assessment method is applied;
• abnormal non-routine operation, in which risk assessment method is applied.
The scope of the two general cases is described below.
When assessing the environmental impacts of routine operation of PV electricity production
with life cycle assessment, the product system includes the manufacturing phase, the use
phase and the end of life phase (see Figure 1). Electronic installation, mounting structure and
power conversion equipment (such as inverters) are included as part of the PV system to be
analysed.
When assessing the risk of non-routine operation of PV modules, the system analysed is
limited to the PV module, its supply chain, operation and end of life treatment, and its direct
electrical and mechanical interfaces with the balance of system, i.e. the electric installation,
mounting structure and inverters.

IEC
Processes of the foreground and background system are marked with blue and red colour, respectively (lighter
coloured line and darker coloured line respectively for monochrome printed version).
Figure 1 – Product system of electricity produced with photovoltaic modules
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 61724-1, Photovoltaic system performance – Part 1: Monitoring
IEC TS 61836, Solar photovoltaic energy systems – Terms, definitions and symbols
ISO/IEC Guide 51, Safety aspect – Guidelines for their inclusion in standards
ISO 14001, Environmental management system – Requirements with guidance for use
ISO 14004:2016, Environmental management systems- General guidelines on implementation
ISO 14040, Environmental management -Life cycle assessment – Principles and framework
ISO 14044:2006, Environmental management – Life cycle assessment – Requirements and
guidelines
– 8 – IEC TS 62994:2019 © IEC 2019
OHSAS 18001: 2009, Guide to implementing a Health & Safety Management System
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14001,
OHSAS 18001, IEC TS 61836 and ISO/IEC Guide 51 as well as the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
Life Cycle Assessment
LCA
compilation and evaluation of the inputs, outputs and the potential environmental impacts of a
product system throughout its life cycle
[SOURCE: ISO 14044:2006,3.2]
3.2
Life Cycle Impact Assessment
LCIA
phase of life cycle assessment aimed at understanding and evaluating the magnitude and
significance of the potential environmental impacts for a product system throughout the life
cycle of the product
[SOURCE: ISO 14044:2006, 3.4]
3.3
Energy Pay Back Time
EPBT
period required for an energy system to generate the same amount of energy (in terms of
primary energy equivalent) that was used to produce the system itself
[SOURCE: Frischknecht R., Heath G., Raugei M., Sinha P. and de Wild-Scholten M.,2015,
Methodology Guidelines on Life Cycle Assessment of Photovoltaic Electricity, 3rd edition.
International Energy Agency, IEA, Paris]
3.4
environmental impact mitigation potentials
quantity of environmental mitigation achievable relative to a baseline or reference case.
Mitigation means the elimination or reduction of frequency, magnitude or severity of exposure
to risks, or minimization of a threat.
3.5
harm
physical injury or damage to persons and livestock
[SOURCE: IEC Guide 116:2010, 3.2, IEC 60050-903:2013, 903-01-01]
3.6
hazard
potential source of harm
[SOURCE: ISO/IEC Guide 51:1999, 3.5, IEC 60050-903:2013, 903-01-02, modified: “Note 2”
deleted]
3.7
risk
combination of the probability of occurrence of harm and the severity of that harm
[SOURCE: IEC Guide 116:2010, 3.13, IEC 60050-903:2013, 903-01-07, modified: “Note 1”
deleted].
3.8
risk analysis
systematic use of available information to identify hazards and to estimate the risk
[SOURCE: ISO/IEC Guide 51:1999, 3.10, IEC 60050-903:2013, 903-01-08]
3.9
risk evaluation
procedure based on the risk analysis to determine whether the tolerable risk has been
achieved
[SOURCE: ISO/IEC Guide 51:1999, 3.11, IEC 60050-903:2013, 903-01-09]
3.10
risk assessment
overall process comprising a risk analysis and a risk evaluation
[SOURCE: IEC Guide 116:2010, 3.15, IEC 60050-903:2013, 903-01-10]
3.11
sustainability
endurance of systems and processes, and in ecology it refers to how biological systems
remain diverse and productive. Sustainability creates and maintains the conditions under
which humans and nature can exist in productive harmony, and that permit fulfilling the social,
economic and other requirements of present and future generations
4 Basic principles of EH&S risk assessment for the PV module
4.1 Basic concepts
Although PV technology has environmental advantages over conventional energy
technologies, the PV industry also uses hazardous materials. Substances that are the subject
of EH&S risk assessment for the PV include flammable, explosive, corrosive, or toxic
materials used in PV industry. Understanding environmental health and safety impacts during
the routine product life cycle and prevention of accidental release of hazardous substances
during non-routine events and reduction of adverse effects are very important for the
sustainability of PV modules. EH&S risk assessment of PV focuses on the emissions of such
substances during the life cycle of PV (usually by the LCA) to characterize environmental
health and safety impacts. EH&S risk assessment for PV also includes consideration of
adverse health or environmental effects resulting from exposures to hazardous agents or
situations (by the Environmental Health & Risk Assessment; EHRA).

– 10 – IEC TS 62994:2019 © IEC 2019
4.2 Life cycle assessment (LCA) of PV
4.2.1 Fundamentals
4.2.1.1 General
These fundamentals describe the basis for the subsequent requirements in this document.
The quantification and reporting of an LCA in accordance with this document are based on the
principles of the LCA methodology provided in ISO 14040 and ISO 14044.
4.2.1.2 Life cycle perspective
The development of LCA quantification and communication takes into consideration all stages
of the life cycle of PV electricity production, including raw material acquisition, production, use
and the end of life stage.
4.2.1.3 Iterative approach
When applying the four phases of LCA (goal and scope definition, life cycle inventory analysis,
life cycle impact assessment and interpretation, see 4.2.3 to 4.2.5) to a LCA study, use an
iterative approach (continuous reassessment as needed when refining the LCA study). The
iterative approach will contribute to the consistency of the LCA study and the reported results.
4.2.1.4 Scientific approach
When making decisions within a LCA, give preference to natural science (such as physics,
chemistry, biology). If that is impossible, use other scientific approaches (such as social and
economic sciences) or refer to approaches contained in conventions relevant and valid within
the geographical scope valid for the LCA study. Permit decisions within a LCA based on value
choices, as appropriate, only if neither a natural scientific basis exists nor a justification based
on other scientific approaches or international conventions is possible, and explain the
rationale for such value choices.
4.2.1.5 Relevance
Select data and methods appropriate to the assessment of the emissions and resource
consumptions arising from the product system being studied.
4.2.1.6 Completeness
Include all emissions and resource consumptions, unit processes and life cycle stages that
provide a significant contribution to the environmental impacts of the product system being
studied.
4.2.1.7 Consistency
Apply assumptions, methods and data in the same way throughout the LCA study to arrive at
conclusions in accordance with the goal and scope definition.
4.2.1.8 Coherence
Select methodologies, standards and guidance documents already recognized and adopted
for PV electricity production to enhance comparability between LCA studies within this
specific product category.
4.2.1.9 Accuracy
Ensure that LCA quantification and communication are accurate, verifiable, relevant and not
misleading and that bias and uncertainties are reduced as far as is practical.

4.2.1.10 Transparency
Address and document all relevant issues in an open, comprehensive and understandable
presentation of information. Notify any relevant assumptions and make appropriate references
to the methodologies and data sources used. Clearly explain any estimates and avoid bias so
that the LCA report faithfully represents its purpose.
Ensure that LCA communication is available to the intended audience and its intended
meaning is presented in a way that is clear, meaningful and understandable. Include
information on functional unit, data assumptions, calculation methods and other
characteristics to make limitations in the comparisons of LCAs transparent and clear to the
target group. Present LCA information so that it is accurate, verifiable, relevant and not
misleading.
4.2.2 Photovoltaics-specific aspects
4.2.2.1 Life expectancy
The recommended life expectancy to be used in LCA of photovoltaic components and
systems and differences between the components are as follows. (If there is ascribed or
declared life expectancy by manufacturer, use it instead):
• Modules: 30 years for mature module technologies (e.g., glass-glass or glass-Tedlar
encapsulation).
• Inverters: 15 years for small plants (residential PV), 30 years with 10 % parts replacement
for large size plants (utility scale PV) .
• Transformers: 30 years.
• Structure: 30 years for roof-top and façades, and between 30 to 60 years for ground
mount installations on metal supports. Sensitivity analyses should be carried out by
varying the service life of the ground-mount supporting structures within the same time
span.
• Cabling: 30 years.
• Manufacturing plants (capital equipment): The lifetime is 10 to 20 years but in some cases
may be shorter than 10 years, due to the rapid development of technology. Assumptions
need to be listed.
4.2.2.2 Irradiation
The irradiation collected by modules depends on their location and orientation. Depending on
the goal of the study, recommendations are given as below:
• Analysis of industry average- and best case-systems:
Assume for all systems on ground that the panels on an array plane are optimally oriented
and tilted at angles equal to the latitude (except when a specific system under study is laid
out differently). Also, assume that roof-top installations are optimally oriented and tilted.
Assume either optimally oriented or case-specific orientation of panels of façade systems.
Additionally, 1-axis or 2-axis tracking systems may be assumed.
In case of higher altitudes and a high diffuse percentage, the optimum tilt angle will be
significantly lower than the latitude. The optimum tilt angle needs to be selected.
——————
Life expectancy may be lower for modules with foil-only encapsulation; this life expectancy is based on typical
PV module warranties
It is recommended that important consumable parts such as cooling fan, MCC board, PLC and PLD should be
replaced every 3 to 4 years.
– 12 – IEC TS 62994:2019 © IEC 2019
• Analysis of the average of installed systems in a grid network:
The average actual orientation, shading and irradiation should be used.
2 2
IEC 61724-1 offers a description of irradiance (W/m ) and irradiation (kWh/m /yr).
4.2.2.3 Performance ratio
Using either site-specific PR values or a default value of 0,75 is recommended for roof-top
and 0,80 for ground-mounted utility installations.
Use actual performance data (actual energy yield in kWh/kWp) of installed technology
whenever available, or make reasonable assumptions that reflect actual performance data
when analysing the average of installed systems in a grid network.
NOTE The performance ratio (PR) (also called derate factor) describes the difference between the modules’ (DC)
rated performance and the actual (AC) electricity generation.
4.2.2.4 Degradation
The degradation of the modules reduces efficiency over the life time. The following degrada-
tion rates are recommended:
• Mature module technologies: Assume a linear degradation declining to 80 % of the initial
efficiency at the end of a 30 years lifetime (i.e., 0,7 %/year, or 10 % on average during the
entire lifetime), unless actual data exist, in which case documentation has to be provided.
When extrapolated from site-specific data, it should be clearly stated whether degradation
is considered or not.
• Use a degradation rate of 0,5 %/year until the end of life (30 years) in a sensitivity
analysis, resulting in an average reduction in the annual yield of 7,5 %.
If a different degradation rate is applied, supporting scientific evidence and test results should
be provided in the LCA report.
• The initial nameplate capacity of the PV module – as printed in the data sheet – shall be
used as the starting point of the degradation curve. Since measurement uncertainties on
performance measurements are factored in the performance tolerance provided on the
data sheet, e.g. +2,5 %/-0 %, the lower value of the nameplate capacity shall be used.
4.2.2.5 Back-up system
Back-up systems such as temporal storage, hydroelectric or gas combined cycle power plants,
or hybrid PV (combinations of PV and diesel aggregates) are considered to be outside the
system boundary of PV LCA.
4.2.3 Life cycle inventory modelling aspects
4.2.3.1 System models
Life cycle inventory (LCI) is the data collection portion of LCA and result of LCIA. The
appropriate system model depends on the goal of the LCA. Depending on the goal and scope
of the study, an attributional, decisional or consequential approach as below can be chosen.
a) Reporting environmental impacts of PV currently installed in a utility's network,
comparisons of PV systems, or of electricity-generating technologies:
retrospective / attributional LCA.
b) Choice of a PV electricity-supplier, or switch of raw material or energy suppliers:
short-term prospective / decisional LCA.
c) Future energy supply situation; comparison of future PV systems or of future electricity-
generating technologies: use long-term prospective LCA / future attributional LCA to
model future static situations.

d) Large scale, long-term energy supply transition; large scale-up of PV in electricity grids of
nations and regions: use consequential LCA to model such transitions.
The following recommendations apply to all goals:
• The product system shall be divided into foreground- and background-processes:
Foreground processes are those which the decision-maker or product-owner can influence
directly and background processes are all remaining processes of the particular product
system (see Figure 1).
• It is recommended to use conventional process-based LCA and follow ISO standards.
• Input-Output- based LCA method: This approach is not recommended for PV system.
(More confidence is needed for its application).
• If a hybrid approach is chosen, report transparently and provide justification for using it.
The following recommendations apply to goal ‘a’ described above (i.e., reporting
environmental impacts of PV currently installed; comparisons of PV systems):
• Assume the present average electricity grid mix for the relevant country (e.g., Europe
(EU 27, including Norway and Switzerland), United States, Korea, China, or Japan) when
modelling the manufacture of current PV components. Specify the year for which the data
are valid.
• If a PV material is produced in a specific country, by a limited number of companies, or if
the PV material production generally involves a specific type of electricity supply, then an
argument can be made for selecting a country or company-specific electricity mix. An
example here is hydropower for producing silicon feedstock in Norway.
• However, country- or company-specific cases shall be clearly reported so that data are not
unintentionally projected to different scales and regions.
The following recommendations apply to goal ‘b’ (choice of a PV electricity-supplier; switch of
feedstock or energy suppliers):
• Assume an annual marginal electricity grid mix for the relevant country. Specify the time
span for which the changes in the grid mix are applicable. Use grid mix data from relevant
national or regional electricity scenario reports to derive the marginal mix.
• Specify the environmental performance and energy efficiency of the power plants
contributing to this marginal electricity mix. The performance of these specific power
plants may differ from national or utility portfolio averages.
• Specify mid-term future marginal market mixes of PV material feedstocks, chemicals,
energy carriers etc. which may contribute significantly to the PV life cycle-based
environmental impacts and where average and marginal mixes may differ substantially.
The following recommendations apply to goal ‘c’ (future energy supply situation):
• Use an annual-average future electricity mix for the relevant country when modelling
future production of PV components. Specify the year for which the forecasted data are
applicable. Use grid mix data from relevant national or regional electricity future scenario
reports.
• Specify the environmental performance and energy efficiency of the power plants
contributing to this future electricity mix. Being power plants operated in the future, they
should represent possible future states.
• If a PV material is expected to be produced in a specific country, by a limited number of
companies, or if the material production generally uses a specific type of electricity supply,
an argument can be made for choosing a country- or company-specific electricity mix, e.g.,
hydropower for producing silicon feedstock production in Norway. However, in prospective
analyses, the availability of country-specific resources to the projected market volumes
shall be documented. Country- or company-specific cases shall be identified clearly, so

– 14 – IEC TS 62994:2019 © IEC 2019
that data are not used unintentionally for projections to different market volumes and
regions.
• Adapt the efficiency of material supply-, transport-, and waste-management-services so
that they represent a possible future state, consistent with the underlying energy-policy
scenario.
The following recommendations apply to goal ‘d’ (large scale, long-term energy supply
transition):
• Identify the main and significant changes in the economy (world-wide) which are caused
by a large scale-up of PV panel installation and production and consequently electricity
production. This may be done by expert interviews, general or partial equilibrium models,
or back casting techniques.
• Identify marginal technologies within the most relevant markets affected by the changes in
the economy. Use forecasting reports published by official bodies or industry associations.
• Establish life cycle inventories of these marginal technologies.
• Adapt the efficiency of future production of materials, transport-, and waste-management-
services so that they represent a possible future state, consistent with the underlying
economic scenario.
• Further aspects such as rebound effects and spill over effects may be taken into account
using economic models (e.g., general or partial equilibrium models), scenario techniques
or other suitable approaches.
• Because consequential LCA is an emerging field and in its short history has not typically
been applied to PV, analysts should conduct a careful literature review to be aware of the
latest developments in the field.
4.2.3.2 Functional unit and reference flow
The functional unit allows consistent comparisons to be made of various PV systems and of
other electricity-generating systems that can provide the same function. The reference flow is
used as the denominator of the cumulative emissions and resource consumptions and the
environmental impacts of the product system under study, whereas the functional unit
specifies the quantified performance of a product system.
The following functional units for PV systems are recommended:
• AC electricity delivered to the grid quantified in kWh is used for comparing PV
technologies, module technologies, and electricity-generating technologies in general. For
grid-connected systems use the kWh of alternate current electricity fed into the grid. For
PV systems with dedicated transformers (e.g., utility solar farms), use the
electricity-output downstream of the transformer.
Alternatively, the reference flows "m " or “kWp (rated DC peak power under STC – Standard
Test Conditions)” may be used. However, these reference flows are not suitable for
comparisons of PV technologies.
• m module is used for quantifying the environmental impacts of a particular building, or of
supporting structures (excluding PV modules and inverters). Square metre is not suited for
comparisons of PV technologies because of differences in module and inverter efficiencies
and performance ratios.
• kWp is used for quantifying the environmental impacts of electrical parts, including inverter,
transformer, wire, grid connection and grounding devices. The kWp may also serve as the
reference flow in quantifying the environmental impacts of an individual module technology.
However, the comparisons of module technologies shall not be based on nominal power
(kWp) figures because the amount of kWh fed to the grid may differ between the systems
analysed.
The location, the module technology used, the voltage level, and whether and how the
transmission and distribution losses are accounted for, shall be specified.

AC electricity may differ in dispatchability and intermittency. Electricity production with one
technology hardly meets all the demand at all times; thus mixtures of power generating
technologies are typically deployed. Aspects of dispatchability or intermittency of AC
electricity produced with different technologies shall not be addressed on technology level but
on the level of grid mixes provided by utilities.
4.2.3.3 System boundaries
The following parts should be included in the system boundaries.
a) Production stage
• Raw material and energy supply
• Manufacture of the panels
• Manufacture of the mounting system
• Manufacture of the cabling
• Manufacture of the inverters
• Manufacture of all further components needed to produce electricity and supply it to
the grid (e.g., transformers for utility-scale PV)
Manufacturing in the product stage of the LCI should cover the following: energy- and
material-flows caused by manufacturing and storage, climate control, ventilation, lighting for
production halls, on-site emissions and their abatement, and on-site waste treatments. PV
manufacturing equipment may be included if data are available.
b) Construction process stage
• Transports to the power plant site (where the plant is operated)
• Construction and installation, including foundation, supporting structures and fencing
c) Use stage
• Auxiliary electricity demand
• Cleaning of panels
• Maintenance
• Repair and replacements, if any
d) End of life stage
• Deconstruction, dismantling
• Transports
• Waste processing
• Recycling and reuse
• Disposal
The following parts should be excluded:
• Commuting (transportation to and from work)
• Administration, marketing, and research and development (R&D) activities.
4.2.3.4 Modelling allocation and recycling
Consistent allocation rules are demanded for all multifunction processes, recycling of
materials, and employing waste heat (e.g., heat recovery in municipal-waste incinerators).
Following ISO 14044:2006, 4.3.4 is recommended.
It is recommended to perform several analyses on material recycling using the recycled
content (cut-off) allocation approach as default and the end of life (avoided burden) recycling
approach in a sensitivity analysis.

– 16 – IEC TS 62994:2019 © IEC 2019
Building integrated PV (BIPV) is a special case of multi-functionality as these PV modules
serve as weather protection and energy producing elements. If required, an allocation of the
manufacturing efforts of BIPV panels shall be done based on clearly described criteria,
avoiding credits as far as possible.
In case system expansion is applied and environmental benefits and environmental impacts
beyond the system boundary are quantified (e.g., using the end of life (avoided burden)
recycling approach), these benefits and loads shall be reported separately. The benefits and
impacts shall be quantified in relation to the net amount of surplus secondary materials or
fuels leaving the product system (all outputs of a secondary material minus all inputs of that
secondary material).
If allocation of multi-output and recycling processes is based on system expansion, the
identification of technologies being displaced is key and choices and assumptions shall be
reasoned and described.
4.2.3.5 Databases
PV specific datasets as well as background LCI (Life Cycle Inventory) databases used to
establish PV LCAs, should comply with transparent documentation and provide unit process
information and data.
4.2.4 Life cycle impact assessment (LCIA)
While a variety of life cycle impact assessment methods are currently available, most widely
used categories and indicators are summarized in Table 1. The following midpoint indicators
are recommended in environmental life cycle impact assessment of PV electricity.
Table 1 – Impact categories and indicators
Impact category Indicator
Climate change Radiative forcing as Global Warming Potential
(GWP 100)
Ozone depletion Ozone Depletion Potential (ODP)
Human toxicity, cancer- effects Comparative Toxic Unit for humans (CTUh)
Human toxicity, non-cancer effects Comparative Toxic Unit for humans (CTUh)
Particulate matter/ Respiratory inorganics Intake fraction for fine particles
(kg PM2.5-eq/kg)
Ionising radiation, human health Human exposure efficiency relative to U235
Ionising radiation, ecosystems Interim
Photochemical ozone formation Tropospheric ozone concentration increase
Acidification Accumulated Exceedance (AE)
Eutrophication, terrestrial Accumulated Exceedance (AE)
Eutrophication, aquatic Fraction of nutrients reaching fresh water end
compartment(P) or marine end compartment
Ecotoxicity (freshwater) Comparative Toxic Unit for ecosystems (CTUe)
Land use Soil organic matter
Resource depletion, water Water use related to local scarcity of water
Resource depletion, mineral Scarcity
Primary energy demand, non renewable Cumulative energy demand, non renewable
Nuclear waste Radiotoxicity potential of nuclear waste

[SOURCE: European Commission 2013]
a) Climate change: Global Warming Potential calculating the radiative forcing over a time
horizon of 100 years.
b) Ozone depletion: Ozone Depletion Potential (ODP) calculating the destructive effects on
the stratospheric ozone layer over a time horizon of 100 years.
c) Human toxicity, cancer effects: Comparative Toxic Unit for humans (CTUh) expressing the
estimated increase in morbidity in the total human population per unit mass of a
carcinogen emitted (cases per kilogramme).
d) Human toxicity, non-cancer effects: Comparative Toxic Unit for humans (CTUh)
expressing the estimated increase in morbidity in the total human population per unit mass
of a non-carcinogen emitted (cases per kilogramme).
e) Particulate matter: Quantification of the impact of premature death or disability that
particulates/respiratory inorganics have on the population, in comparison to PM . It
2.5
includes the assessment of primary (PM and PM ) and secondary PM (including
10 2.5
creation of secondary PM due to SO , NO and NH emissions).
...