ENERG-ICE LCA
Life Cycle Assessment
ENERG-ICE,
ICE, a new polyurethane foam technology for the cold
appliance industry
Commissioned by the Dow Italia & Dow Polyurethanes business unit
With the support of LIFE08 ENV/IT 000411
Chartered: November, 2012
Completed: May, 2013
Authors:
Dr. Richard Helling
EH&S / Sustainability
Vanni Parenti
Dow Polyurethanes
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TABLE OF CONTENTS
EXECUTIVE SUMMARY............................................................................................................................. 3
INTRODUCTION ....................................................................................................................................... 4
GOAL....................................................................................................................................................... 8
SCOPE ..................................................................................................................................................... 8
Function .............................................................................................................................................. 8
Functional Unit .................................................................................................................................... 9
System Boundaries .............................................................................................................................. 9
Consideration of Capital Equipment and Buildings ......................................................................... 10
Transportation of Raw Materials.................................................................................................... 10
Life cycle impact assessment ............................................................................................................. 10
Critical Review ................................................................................................................................... 11
LIFE CYCLE INVENTORY ANALYSIS .......................................................................................................... 11
Data Collection and Sources .............................................................................................................. 11
Process models.................................................................................................................................. 13
Consistency ....................................................................................................................................... 13
Data Validation.................................................................................................................................. 13
Allocation and cut-off criteria ............................................................................................................ 14
LIFE CYCLE IMPACT ASSESSMENT .......................................................................................................... 14
LCIA Methods .................................................................................................................................... 14
Global Warming Potential.............................................................................................................. 15
Energy Use .................................................................................................................................... 15
Water ............................................................................................................................................ 15
Acidification Potential.................................................................................................................... 16
Eutrophication Potential................................................................................................................ 16
Photochemical Oxidant Creation Potential..................................................................................... 16
Ozone Depletion Potential............................................................................................................. 16
Toxicity: Human cancer, human non-cancer and ecological........................................................... 16
General LCIA Comment.................................................................................................................. 16
LIFE CYCLE INVENTORY .......................................................................................................................... 16
LIFE CYCLE INTERPRETATION (RESULTS AND DISCUSSION)..................................................................... 17
Cradle-to-grave.................................................................................................................................. 17
Cradle-to-gate ................................................................................................................................... 19
Toxicity.............................................................................................................................................. 22
Uncertainty and sensitivity analyses .................................................................................................. 24
Data quality assessment .................................................................................................................... 25
CONCLUSIONS....................................................................................................................................... 25
RECOMMENDATIONS/FUTURE WORK ................................................................................................... 26
CRITICAL REVIEW................................................................................................................................... 26
ACKNOWLEDGMENTS ........................................................................................................................... 26
APPENDIX.............................................................................................................................................. 27
Critical review letter .......................................................................................................................... 27
REFERENCES.......................................................................................................................................... 30
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EXECUTIVE SUMMARY
Life Cycle Assessment (LCA) is a useful methodology for examining the total environmental impact of a
product or service, such as a household appliance. Refrigerators are a major contributor to household
energy use, and their performance has improved dramatically over the last 20 years. A key part of their
performance is effective foam insulation in the walls of the appliance. Dow has collaborated in the
development of new production technology for high-efficiency refrigerators.
The goal of this study was to understand the potential burdens and benefits of using the new
polyurethane (PU) foam technology, called “ENERG-ICE”, and how this may be an improvement over
current technology, especially with respect to the production process and inputs. The functional unit
was polyurethane insulation for one refrigerator for 12 years of domestic use, using a cyclopentane
blowing agent and either the new or conventional production methods. The study considered the
impact categories of global warming potential (GWP), acidification potential (AP), freshwater and
marine eutrophication potential (EP), photochemical oxidant creation potential (POCP) (smog), ozone
depletion potential (ODP), water depletion and fossil resource depletion.
Electricity consumption during the use phase of a refrigerator is the dominant source of potential
environmental impacts. Use of insulation with improved performance is a way to reduce burdens from
use of refrigerators. The new technology allows for a measured 10% less electricity use (all other things
remaining the same) which translates to about 10% reduction in all potential cradle-to-grave impacts.
Due to the dominance of the use phase, uncertainty about specific production or end-of-life inputs,
including the choices of background data sets, would not have a significant impact on the results.
On a cradle-to-gate perspective, the new technology offers a small but plausible advantage in all impacts
considered, primarily due to the less mass required to get the same performance. The benefit of
reduction in heat and power to the process was small compared to the benefit from the reduced mass.
This work was done in accordance with ISO standards for a project not making a comparative assertion
and has received a critical peer review by Dr. Martin Baitz of PE INTERNATIONAL AG. This version is the
“public report”, for which confidential information, that was available to the reviewer under a secrecy
agreement, has been removed. This information included detailed compositions and the SimaPro
process models.
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INTRODUCTION
Life Cycle Assessment (LCA) is a useful methodology for examining the total environmental impact of a
product or service. Rather than focusing on a single process, LCA takes a holistic view, examining
environmental impacts over the complete “cradle-to-grave” product life cycle. LCA requires that the
upstream life cycle phases (raw materials acquisition and processing), downstream phases (fabrication,
use, and end-of-life treatment), and all transportation phases be examined in addition to the
manufacturing phase that Dow has historically focused on. Results from LCA address the complete
environmental impact of a product, and are hence more meaningful than those obtained for a single
process or step in the life cycle. A life cycle perspective helps to ensure that environmental burdens are
not unintentionally transferred from one life cycle phase to another during process improvement, and
thus helps to prevent unintended environmental consequences.
LCA is framed by ISO standards 14040 and 14044 [1,2] which provide comprehensive guidelines for
conducting an LCA study. ISO defines four phases of an LCA study:
1.
2.
3.
4.
Goal and Scope definition
Life Cycle Inventory (LCI)
Life Cycle Impact Assessment (LCIA)
Life Cycle Interpretation
Details on each of these phases are provided in the ISO standards and in many external references,
which also give good insight on the uses and limitations of LCA [3,4,5]. Previous Dow reports and
publications [6,7,8, 9,10] give examples of the use of LCA at Dow.
One can apply LCA methodology and tools to a portion of the life cycle, as a building block for a
complete LCA, and a useful way to answer some questions. “Eco-profiles” are an example of partial LCA
that covers the “cradle-to-gate” stages for a material, and can be used to create complete LCA for
downstream uses of these materials. These are typically created with great detail and extensive data.
Examples include those assembled for PlasticsEurope, which are collected by conducting surveys of
multiple plants producing the same material [11]. The surveys include all mass and energy inputs to a
process, amounts and uses of water, and a complete description of air, water and solid waste emissions.
A “carbon footprint” is a subset of LCA data, considering only greenhouse gas emission, and can be
synonymous with the calculation of the “global warming potential”. Carbon footprints can be done on a
cradle-to-gate or a cradle-to-grave basis.
Refrigerators are a major contributor to household energy use, and their performance has improved
dramatically over the last 20 years [12]. The Ecodesign Directive and the Energy Label Directive cover
the use phase of European Energy using products (EuP), which accounts for 80-90% of the industry’s
environmental impact. The legislation helps drive the least efficient products from the market. As
illustrated on the Figure 1, a cold appliance on the market today consumes less than half of the energy
used 20 years ago [13]. Ecodesign policy also plays a key role in pushing the market towards more
energy and water efficient appliances.
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Figure 1: European cold appliance energy efficiency improvement over time
The EU Energy Label is proving to be a key instrumen
instrumentt in driving consumers towards cold appliances that
are more efficient in terms of energy consumption. The Energy
E
label improvement in Europe is shown in
Figure 2,, along with an example of a refrigerator labeling [[14].
]. Labeling and regulations can have a
strong
trong effect on consumer behavior and the development of new and improved products
products. As shown in
the figure, the categories of “C” and above were no longer relevant in 2005,, and the categories
c
of
“A+”and “A++” needed to be created.
Figure 2:: European refrigerator label and efficiency improvement over time
A++
124
115
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More stringent energy regulations have been implemented by the European Community to gradually
improve the energy efficiency of appliances sold in the market place to meet the 20% savings target by
2020. As a consequence, only class A or better could be commercialized in Europe from June 2010; as of
June 2012 only class A+ or better are allowed [15].
A key part of the improved performance of refrigerators is effective foam insulation in the walls of the
appliance. Polyurethane (PU) foams, formed by the reaction of a polyol with an isocyanate, and the use
of a blowing agent and additives, are particularly effective in manufacturing appliances. They offer very
low thermal conductivity with the ability to fill completely open cavities of any geometry in the walls of
an appliance [16].
The European Union, through the LIFE program, has co-financed pilot or demonstration projects with
European added value and with the general objective to contribute to the implementation, updating
and development of EU environmental policy and legislation. The LIFE+ phase of the program (20072013) has a budget of €2.143 billion [17]. One of the projects receiving LIFE+ funds is “ENERG-ICE”, a
combined effort of Dow Italia, CANNON – Afros division, CANNON – Crios division, and Federchimica
[18]. The aim of the project was to demonstrate the potential for reducing the environmental impact of
energy-using products (EuP), such as cold appliances, by taking action at the design stage, where the
pollution caused during the product's life cycle can be best prevented. The project focused on an
innovative PU foaming technology for manufacturing the insulation filling material of cold appliances
(both refrigerators and freezers) using cyclopentane as a blowing agent. To quantify the potential
environmental impacts of this new process, an LCA was done.
Historically, PU foams were made using a chloroflurocarbon (CFC) as the blowing agent. Concerns over
the ozone depletion potential (ODP) of these materials and the adoption of the Montreal Protocol led to
the replacement of CFC with HCFCs (hydrochlorofluorocarbons) and HFCs (hydrofluorcarbons). HFCs
such as HFC-245fa and HFC-134a were developed as zero-ODP substances replacing CFCs, but do have a
significant global warming potential (GWP), 1250 and 1600 kg CO 2eq/kg[19]. An alternative approach is
to use a hydrocarbon (HC) blowing agent, such as cyclopentane, that has zero ODP and low GWP (11
CO2eq/kg).
Two concerns with the use of HC blowing agents are that they are flammable (a concern primarily during
manufacturing) and that they have not been able to produce a foam with as low a thermal conductivity
as HFCs. Dow has collaborated with CANNON in the development of new polyurethane formulations
and production technology for using HC blowing agents in PU foam insulation in high-efficiency
refrigerators[20]. Data from tests of refrigerators using the new and old technology are shown in Table 1
[21]. In this figure, the data row “RHL” stands for “reverse heat leakage”, a performance test for
insulation conducted on a semi-assembled refrigerator. Data are presented for cyclopentane and HFC245fa blown foam refrigerators; the data for HFC-245fa are presented as a familiar benchmark for the
global industry, but it is not used in Europe or in this study. The top half of the table shows that use of
the HFC-245fa blowing agent could decrease heat loss (and energy use) of an otherwise identical
refrigerator by 10% compared to one using conventional technology and cyclopentane; the lower half
of the table shows that the new production method using cyclopentane can also achieve a 10%
reduction from current performance. This is a key performance benefit enabled by the new technology.
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Table 1: Performance data for conventional and new PU technology
In the conventional manufacturing process, the foaming is done at atmospheric pressure and some
blowing agent is released to the air in the factory, which requires adequate ventilation. In the new
process, the foaming is done under vacuum which allows for better foam properties (lower thermal
conductivity), superior process behaviors (faster cycle time), cost advantages (lower applied density)
and capture of the released blowing agent. The process has been run successfully in a full-scale pilot
unit (shown in Figure 3); detailed designs for commercial production lines have been made.
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Figure 3: ENERG-ICE pilot plant
This work was done in accordance with ISO standards [1, 2] for a project not making a comparative
assertion and has undergone a critical peer review by PE INTERNATIONAL AG. A non-confidential public
report will be created. The study will be used to validate attributes of the new technology.
GOAL
The goal of this study was to understand the potential burdens and benefits of using the new
polyurethane (PU) foam technology, called “ENERG-ICE”, and how this may be an improvement over
current technology, especially with respect to the production process and inputs. The study will be
used to validate attributes of the new technology.
The target audience for this report is the Dow technical community, specifically Dow polyurethanes
R&D, and the EU Life+ project administration. The work will be a part of the overall project deliverables.
A final audience would be refrigerator producers, for whom the information would be helpful in
decisions about technology choices for new or modified production facilities. Dow intends to continue
to provide materials that can be used in both technologies included in this study.
SCOPE
Function
The function of the ENERG-ICE technology is to enable safe polyurethane (PU) foam insulation in the
shell of cold appliances such that high efficiency refrigerators can be produced.
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Functional Unit
The functional
ctional unit was polyurethane insulation for one refrigerator for 12 years of domestic use, using
a hydrocarbon blowing agent and either the new or conventional production methods.
methods. When using the
conventional technology, the refrigerator would meet EU class A performance; when using the new
technology, the performance of the refrigerator is improved by 10%.
System Boundaries
This was a cradle-to-grave study, so the boundaries
boundaries extended upstream to materials in the earth and
continued to disposal of the refrigerator at the end of life.
life Manufacturing and use was assumed to be
done in Europe, using average utility inputs for Europe. The choice of PU foam technology is
independent
ent of other design features, so all other aspects of and inputs to refrigeration production are
assumed to be the same (i.e., interior and exterior dimensions, compressors, metals, plastics, shelves,
wiring),, and cancel out in an analysis of foam production methods. A high level view of the life cycle
stages and the primary direct inputs and emissions is shown in Figure 4,, and a conceptual drawing of PU
foam production is shown in Figure 5.
Figure 4:: High level view of life cycle stages (showing only direct inputs and emissions)
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Figure 5: Conceptual flowsheet for PU foam production
Consideration of Capital Equipment and Buildings
Process equipment is one of the key differences between the two technologies, so could not a priori be
neglected, although typically it has minimal impact on chemical production processes [22]. Cost data
were available for the equipment required for same production line used for the energy and utilities
data (shown in Table 3) [23]. We assumed that cost of similar items is an appropriate surrogate for mass
and other burdens, using the concepts of economic input-out LCA [24]. Euros were converted to 2012
US dollars at the rate of $1.29/€, based on Dow currency exchange data, and then converted to 2002 US
dollars using the US consumer price index [25]. The result was $1.87 million and $1.84 million (2002).
There was very little difference in cost between the two options – the fewer units needed for the new
technology is balanced with the increased complexity. These costs were incorporated into the SimaPro
models as “Metal cutting and forming machine tool manufacturing”.
Buildings and other infrastructure was not included, as it would be the same for both production
technologies.
Transportation of Raw Materials
Transportation was included for all inbound raw materials, assuming 200 km of transport by truck. No
transport was included for equipment, for non-foam parts of the refrigerator, or for life cycle stages
beyond production. These will be the same for both production methods.
Life cycle impact assessment
The study considered the impact categories of global warming potential (GWP), fossil resource
depletion, acidification potential (AP), freshwater and marine eutrophication potential (EP),
photochemical oxidant creation potential (POCP) (smog), ozone depletion potential (ODP), water
depletion, human toxicity and ecotoxicity.
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Critical Review
Critical review ensures consistency between a life cycle assessment and the ISO requirements for it. The
main purpose of a critical review is to ensure a well defined, expertly executed, transparent LCA that
complies with ISO standards for LCA. The critical review for LCAs not involving comparative assertions
may be carried out by an internal or external expert, independent of the LCA project team. The
reviewer’s role it is to determine if:
•
the methods used to carry out the LCA are consistent with the ISO standards,
•
the methods used to carry out the LCA are scientifically and technically valid,
•
the data used are appropriate and reasonable in relation to the goal of the study,
•
the interpretations reflect the limitations identified and the goal of the study, and
•
the study report is transparent and consistent.
A critical peer review was conducted by Dr. Martin Baitz of PE INTERNATIONAL AG.
LIFE CYCLE INVENTORY ANALYSIS
Data Collection and Sources
Data were collected from the ENERG-ICE project team members, Dow and CANNON, for the energy and
material inputs for production and use of the current and new technology. Ecoinvent was the usual
source of background data. Details of the specific data sources and assumptions follow.
A critical difference between the current and new technology is the composition of the polyurethane.
The composition details for the two foams are given in Table 2, taken from Dow specifications (“Low K”
is the current technology):
Table 2: Compositions of polyurethane foam for current and new technologies
Polyol Reference No
DSD
426.01
DSV
1103.01
Type
Low K
Energ-Ice
93.2
78.5
Polyether polyol
Polyester polyol
15
WATER
2.4
1.4
Amine catalyst system
2.4
2.6
2
2,5
Total Polyol
100
100
Polymeric MDI
150
134
14
16
264
250
14,700
14,000
Silicone surfactant
Blowing agent (cyclopentane)
TOTAL MATERIAL RECIPE
kg per production day
The choices and their rationales for transforming the descriptions used in the Dow data sources to the
SimaPro models of them are described in the following:
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




Polyols (including glycerin). Each formulation includes a blend of different base Polyols.
Although these are Dow-produced materials, we have modeled them using the ecoinvent model
for “Polyols, at plant/RER U”, as a reasonable representation of spectrum of polyols that are
commercially available and could be used with this technology. The ecoinvent model is in turn
based on PlasticsEurope data, including data provided by Dow. A distinct model for glycerin was
not included, rather it is an initiator used is some of the polyols described by the data set.
Isocyanate. Each formulation includes polymethylene polyphenylisocyanate. Although the
specified material is Dow-produced, we have modeled them using the ecoinvent model for
“Methylene diphenyl diisocyanate, at plant/RER U” (MDI), as a reasonable representation of
MDI that is commercially available and could be used with this technology. The ecoinvent
model is in turn based on PlasticsEurope data, including data provided by Dow.
Amine catalyst system. The specific materials are not included in a database, but do include
amine functionality. As a surrogate, assume all the amine catalysts can be modeled as EDTA
(“EDTA, ethylenediaminetetraacetic acid, at plant/RER S”).
Silicon surfactant. Since exact composition is not known, model as trimethoxyoctylsilane, an
equi-molar mix of 1-octene and trimethoxysilane. Models for these were created in previous
Dow projects, with 1-octene based on Dow and IHS/SRI [26] data, and trimethoxysilane from US
patent 5,084,590A [27].
Cyclopentane. Cyclopentane exists as a chemical species in SimaPro, so that emission of
cylcopentane are included as such and included in any impact assessments that have
characterization factors for cyclopentane. A process model did not exist in Ecoinvent for
cyclopentane, so “methycyclopentane, from naphtha” was used as a surrogate for this small (by
mass fraction) component.
In addition to material inputs, there are energy inputs to the foam production processes. These data are
taken from detailed design calculations for new process equipment by CANNON – Afros, and
incorporates experience gain from the Dow/CANNON pilot plant operations [28]. Note that the
equipment and utility specifications are set to meet the same production rate.
Table 3: Utility and production line specifications per day of operation
Item
Units per day
“Fixtures” or “Masks”
Conventional
2880
12
New
2880
8
Process heat, MJ
2853
2717
Mask temperature
control heat, kWh
Ventilation fan, kWh
1008
672
250
175
Vacuum pump, kWh
0
30
Comment
1 per 30 seconds
Production stations. New technology
offers faster cycle time, so need fewer
units for same throughput
Thermal conditioning of materials at
dosing unit. Reduction due to less mass
of materials. Assume supplied by hot
water (listed amounts are at boiler)
Electrical heat. Reduction due to fewer
units
Although might in principle be reduced to
zero, assume only a 30% reduction to be
conservative
Only exists in new technology
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The choices and their rationales for transforming the descriptions used in the CANNON design to the
SimaPro models of them are described in the following:


Electricity is assumed supplied from the grid, at medium voltage. Although the ENERG-ICE pilot
plant was in Italy, the study was done under generic EU conditions, as the results should be valid
throughout the EU. The specific model selected was “Electricity, medium voltage, production
UCTE, at grid/UCTE U”.
Similarly for process heat for thermal conditioning, although the ENERG-ICE pilot plant was in
Italy with a specific heat source, the study was done under generic EU conditions. Heat was
assumed to be provided by hot water, supplied in turn at 85% system efficiency from a small,
modern, gas-fired boiler: “Heat, natural gas, at boiler condensing modulating <100kW/RER U”.
In addition to the process inputs, the sole input to the use phase was 12 years of electricity consumption
at (303 kWh/yr) [29], which is an A-class refrigerator. The potential impacts were calculated using the
model “Electricity, low voltage, production UCTE, at grid/UCTE S”, which is representative of household
use anywhere in Europe. A twelve year product life is typical for refrigerators [30].
Burdens for the end of life are included by adding the ecoinvent model for “Disposal, polyurethane,
0.2% water, to municipal incineration/CH S”. This is based on the assumption that at end of life all foam
insulation is incinerated (any that is land-filled will be largely inert). Burdens from non-foam parts are
same for both technologies and not included in the analysis. As a sensitivity analysis, a scenario is
included which has all of the blowing agent released prior to incineration, during dismantling and
shredding of the refrigerator.
Process models
The primary sources of information for PU foam production were Dow and CANNON technical experts,
including results from lab, pilot, and commercial operations. SimaPro 7.3.3 from Pré Consultants was
the life cycle assessment software used in this study. Dow data and other data were used directly to
create process models in SimaPro. Ecoinvent v2.2 [31], a comprehensive database of over 4000 life
cycle inventory data sets, was used within SimaPro to model utility process operations, transportation,
packaging, and other material inputs. SimaPro process models (abridged to eliminate non-critical
information) for all the products and processes are included in the Appendix. There are comments
there that provide additional detail (albeit unedited) to the descriptions above. These are also available
as comma delimited files (.CSV), suitable for import into SimaPro, from the lead author and in the CRI
supporting documents.
Consistency
A quantitative consistency check was not included in this study. Qualitatively, the use of a small number
of data sources was believed to allow collection of primary data with consistent age, quality and detail.
All data are from operation in Europe.
Data Validation
The lead author on the project is a registered Professional Engineer in the State of Michigan and
provided detailed review of the data provided by the project team members with respect to mass
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accountability and the reasonableness of engineering design calculations.
data collection process.
This was done during the
Allocation and cut-off criteria
The modeled assembly lines are assumed to produce a single product (model), so no allocation is
needed. Allocation is done for the use phase burdens, in that all the burdens from electricity
consumption are included, but the project scope and boundaries do not include all the things that might
influence the energy use (such as pumps, compressors, shell, ambient temperature, consumer
behavior). The effect of this allocation is considered in the sensitivity analysis.
Cut-off criteria are conditions that specify how much of the data obtained in the study will be used in
modeling the system. For an extremely detailed life cycle inventory, accounting for every input is likely
to be impractical within reasonable time constraints; hence, cut-off criteria help guide the rationale for
excluding any data. To provide a robust and credible analysis, and to thereby enhance the credibility of
the study, the approach taken towards cut-off criteria in this study was to include as much of the life
cycle inventory data in the models as possible. All the known inputs from the Dow Polyurethanes and
CANNON have been included. The implicit cut-off for this data source is relevance: inputs and outputs
related directly to the foam production operation are included; ancillary inputs (office supplies and
travel, for example) are not included.
LIFE CYCLE IMPACT ASSESSMENT
LCIA Methods
Life cycle impact assessment (LCIA) was performed using valuation systems available in Ecoinvent, and
primarily that of ReCiPe [32,33], using “midpoint” metrics and with no normalization to a target or
weighting of different impact categories. We examined the midpoint impact categories listed in Table 4.
Fossil resource use, global warming, acidification (acid rain-forming emissions), eutrophication (addition
of limiting nutrients P or N to lakes, rivers, and streams), stratospheric ozone depletion, photo-oxidant
creation (low level smog formation), human toxicity and ecotoxicity are important environmental
categories that have been examined frequently in LCA studies. Details on the mechanisms and potential
environmental impacts (endpoints) associated with these categories are provided by Bare et al. [34].
To calculate the impact category indicators, we primarily used the ReCiPe method for midpoint impacts,
without any normalization or weighting. The ReCiPe system is described by Goedkopp et al. [35]. We
did not use all the possible impact categories available in ReCiPe, only the ones listed in Table 4. For
toxicity, we used the USEtox method. ReCiPe and USEtox have been implemented in Ecoinvent [36] and
SimaPro. Comments on the specific metrics follow.
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Table 4: Impact Categories examined
Impact Category
Climate Change
Fossil resource depletion
Water Depletion
Terrestrial Acidification
Freshwater Eutrophication
Marine Eutrophication
Summer Smog Creation
Stratospheric Ozone
Depletion
Human toxicity
Human toxicity
Ecotoxicity
Indicator
Global Warming
Potential (GWP)
Fossil resource
depletion (FD)
Water withdrawals
Unit
[kg CO2–eq]
Method
ReCiPe Midpoint (H)
[kg oil eq]
ReCiPe Midpoint (H)
[m3]
ReCiPe Midpoint (H)
Acidification Potential
(AP)
Eutrophication
Potential (EPf)
Eutrophication
Potential (EPm)
Photochemical
Oxidant Creation
Potential (POCP)
Ozone Depeltion
Potential (ODP)
Human toxicity,
cancer
Human toxicity, noncancer
Ecotoxicity
[kg SO2–eq]
ReCiPe Midpoint (H)
[kg P–eq]
ReCiPe Midpoint (H)
[kg N–eq]
ReCiPe Midpoint (H)
[kg NMVOC]
ReCiPe Midpoint (H)
[kg CFC–11 eq]
ReCiPe Midpoint (H)
[CTUh]
USEtox TM Model
[CTUh]
USEtox TM Model
[CTUe]
USEtox TM Model
Global Warming Potential
Climate change impact is a global issue with well-established characterization factors. ReCiPe uses the
IPCC 2007 values [37].
Energy Use
Although all forms of energy are important and fungible, we report the cumulative energy demand from
fossil resources as these are the most limiting and of greatest interest.
Water
Although not an impact assessment, a water inventory was calculated. It includes only fresh (river, lake,
well, unspecified) water withdrawals for consumptive uses - not cooling or process use and is known as
“water depletion” in ReCiPe’s nomenclature. This does not include “barrage” or water behind a dam
that will be used for hydroelectric power or turbines. Water is an issue of increasing global importance,
though often not as critically in Europe as in other regions.
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Acidification Potential
For Acidification Potential, ReCiPe use an average European characterization system of Huijbregts et al.,
[38], which accounts for fate and sensitivity of the receiving ecosystem. This is applicable to European
emissions and is a method used in many previous Dow studies.
Eutrophication Potential
For Eutrophication Potential, ReCiPe allows calculation of both freshwater eutrophication (P-limited,
based on P-containing emissions to soil and water only) and marine eutrophication (N-limited, based on
nitrogen-containing emissions to soil, water and air). In both cases European fate and transport models
are used. This is applicable to European emissions and is a method used in many previous Dow studies.
Photochemical Oxidant Creation Potential
For POCP, ReCiPe uses characterization factors from Derwent et al. [39] in the mid-point impact method.
Ozone Depletion Potential
ODP characterization factors can be calculated for different time horizons. ReCiPe uses “steady state”
values.
Toxicity: Human cancer, human non-cancer and ecological
The USEtox™ model is an environmental fate and transport model for characterization of human and
ecotoxicological impacts in Life Cycle Impact Assessment (LCIA) and Comparative Risk Assessment (CRA),
[40,41]. It has been developed through the UNEP SETAC initiative for use in LCA, and covers a wider
range of chemicals than other toxicity methods. Although Dow has not historically reported toxicology
impact assessments in LCA due to the greater uncertainty in the models, USEtox is potentially the mostly
widely used and applicable method globally. It is important to note that differences of an order of
magnitude or more are needed to discern significant differences in toxicity in USEtox. Toxicity is
reported in CTU, or comparative toxic units.
General LCIA Comment
The LCIA results presented in this study are relative expressions, and do not predict impacts on category
endpoints, the exceeding of thresholds, safety margins, or risks.
LIFE CYCLE INVENTORY
The primary energy (including feedstock energy) and water inputs and waste outputs are summarized in
Table 5 for a class A refrigerator produced with conventional technology using cyclopentane as a
blowing agent, operated for 12 years, and incinerated at the end of life. The use phase, which includes
only electricity consumption, is most significant life cycle stage in the consumption of resources and
generation of emissions.
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Table 5: Summary of inventories by life cycle stage
Primary energy
Water (includes use in
turbines)
Water (depletion)
Emissions to soil
Emissions to water
Production & upstream
0.99%
0.04%
Use
99%
99.95%
End of life
0.01%
0.01%
1.6%
0.66%
18.4%
98%
99.3%
81%
0.04%
0.04%
0.6%
LIFE CYCLE INTERPRETATION (RESULTS AND DISCUSSION)
Cradle-to-grave
The contributions to the GWP for a class A refrigerator produced with conventional technology using
cyclopentane as a blowing agent and operated for 12 years are shown in a “Sankey” diagram using a
0.0082% display cut-off, Figure 6. The total GWP for this technology is 2190 kg CO2eq/refrigerator. The
figure allows one to quickly identify that the key contributor to the GWP is the use phase, which is
responsible for 98.5% of the GWP. The end of life contributes 0.6%, and the balance (about 1%) is
related to production inputs.
Figure 6: Contributions to GWP for conventional technology
1p
Refrigerator
insulation,
conventional PU
100%
2.9 kg
Methylene
diphenyl
diisocyanate, at
0.532%
1.8 kg
Polyols, at
plant/RER U
0.302%
0.13 kg
Disposal,
hazardous waste,
25% water, to
0.0144%
0.27 kg
Methylcyclopentan
e, from naphtha,
at plant/RER U
0.0111%
0.0236 kg
Trimethoxysilane
from metal, at
plant/DE
0.00823%
2.02 MJ
Electricity, medium
voltage,
production UCTE,
0.0135%
0.0858 kg
EDTA,
ethylenediaminete
traacetic acid, at
0.0188%
1.31E4 MJ
Electricity, low
voltage,
production UCTE,
98.5%
5.1 kg
Disposal,
polyurethane,
0.2% water, to
0.575%
2.1 MJ
Electricity, high
voltage,
production UCTE,
0.0137%
2.13 MJ
Electricity,
production mix
UCTE/UCTE U
0.0137%
The picture is essentially identical for the refrigerator produced using new technology and cyclopentane,
as shown in Figure 7: 98.5% from use phase electricity, 0.6% from end of life and the balance from
production and upstream inputs. The magnitude is 1970 kg CO2eq/refrigerator, which is 10% less.
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Figure 7: Contributions to GWP for new technology
1p
Refrigerator
insulation, new
technology PU
100%
2.61 kg
Methylene
diphenyl
diisocyanate, at
0.531%
1.82 kg
Polyols, at
plant/RER U
0.338%
0.128 kg
Disposal,
hazardous waste,
25% water, to
0.0158%
0.311 kg
Methylcyclopentan
e, from naphtha,
at plant/RER U
0.0142%
0.0465 kg
EDTA,
ethylenediaminete
traacetic acid, at
0.0113%
0.0257 kg
Trimethoxysilane
from metal, at
plant/DE
0.00995%
1.57 MJ
Electricity, medium
voltage,
production UCTE,
0.0117%
1.18E4 MJ
Electricity, low
voltage,
production UCTE,
98.5%
4.86 kg
Disposal,
polyurethane,
0.2% water, to
0.608%
1.65 MJ
Electricity, high
voltage,
production UCTE,
0.0119%
1.67 MJ
Electricity,
production mix
UCTE/UCTE U
0.012%
Results for all the impact categories calculated using the selected ReCiPe methods are shown in Figure 8
for the cradle-to-grave life cycle of the refrigerator insulation, using cyclopentane as the blowing agent
and both conventional (on the left) and new (on the right) technologies. For all the impact categories,
the results have been normalized by the maximum value of the two, which for all categories is the
conventional. The specific maximum values for each impact category are (per refrigerator used for 12
years):
 Climate change (GWP): 2,190 kg CO2 eq
 Ozone depletion (ozone depletion potential, ODP):0.000107 kg CFC-11 eq
 Terrestrial acidification (acidification potential, or AP): 9.3 kg SO 2 eq
 Freshwater eutrophication (eutrophication potential, or EPf: 2.23 kg P eq
 Marine eutrophication (eutrophication potential, or EPm): 0.627 kg N eq
 Photochemical oxidant formation (photo oxidant creation potential, or POCP): 4.66 kg NMVOC
(non-methane volatile organic carbon)
 Water depletion: 18 m3
 Fossil resource depletion: 596 kg oil eq
In all cases, production and upstream inputs contribute less than 2% of the potential impact, and the
values for the new technology were 10% less, due to the lower electricity use (based on measured
performance). Use of insulation with improved performance is a way to reduce burdens from use of
refrigerators.
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Figure 8: Selected cradle-to-grave ReCiPe categories per refrigerator
100
95
90
85
80
75
70
65
60
%
55
50
45
40
35
30
25
20
15
10
5
0
Climate change
Ozone depletion
Terrestrial
acidification
Freshwater
eutrophication
Refrigerator insulation, conventional PU foam w use and EOL/ RER U
Marine eutrophic
ation
Photochemical
oxidant formatio
Water depletion
Fossil depletion
Refrigerator insulation, new technology PU foam w use EOL/ RER U
Comparing 1 p 'Refrigerator insulation, conventional PU foam w use and EOL/ RER U' with 1 p 'Refrigerator insulation, new technology PU foam w use EOL/ RER U';
Method: Recipe Midpoint (H) V1.07 / World ReCiPe H / Characterization
We looked at the cradle-to-gate impacts to gain a better understanding of the impacts of production
technology.
Cradle-to-gate
The contributions to the cradle-to-gate GWP for production of one refrigerator to EU Class A standard
using cyclopentane blowing agent and conventional insulation technology are shown (with a 0.65%
display cut-off) in Figure 9. The GWP is 19.8 kg CO 2eq/refrigerator, of which 97% of the burden is due to
materials (92% from the major materials, polyols & MDI). Transport, equipment, and process electricity
each contribute about 1%.
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Figure 9: Sankey diagram for cradle-to-gate contributions to GWP of conventional insulation
technology
1p
Refrigerator
insulation,
conventional PU
100%
2.9 kg
Methylene
diphenyl
diisocyanate, at
59%
1.8 kg
Polyols, at
plant/RER U
33.5%
0.27 kg
Methylcyclopenta
ne, from naphtha,
at plant/RER U
1.23%
0.13 kg
Disposal,
hazardous waste,
25% water, to
1.59%
0.0236 kg
Trimethoxysilane
from metal, at
plant/DE
0.913%
2.02 MJ
Electricity, medium
voltage,
production UCTE,
1.5%
0.0288 kg
MG-silicon, at
plant/NO S
2.1 MJ
Electricity, high
voltage,
production UCTE,
1.52%
0.727%
0.0858 kg
EDTA,
ethylenediaminete
traacetic acid, at
2.08%
0.266 USD
Metal cutting and
forming machine
tool
0.653%
1.02 tkm
Transport, lorry
16-32t,
EURO4/RER S
0.853%
2.13 MJ
Electricity,
production mix
UCTE/UCTE U
1.52%
A similar diagram for the new technology is shown in Figure 10, where the 18.5 kg CO2eq/refrigerator is
97% due to materials (93% from the major materials, polyols & MDI), and transport, equipment, and
process electricity each contribute about 1%.
Figure 10: Sankey diagram for cradle-to-gate contributions to GWP of new insulation technology
1p
Refrigerator
insulation, new
technology PU
100%
2.61 kg
Methylene
diphenyl
diisocyanate, at
56.8%
1.82 kg
Polyols, at
plant/RER U
36.2%
0.128 kg
Disposal,
hazardous waste,
25% water, to
1.68%
0.311 kg
Methylcyclopenta
ne, from naphtha,
at plant/RER U
1.51%
0.335 kg
Naphtha, at
refinery/RER U
0.734%
0.0465 kg
EDTA,
ethylenediaminete
traacetic acid, at
1.21%
0.0257 kg
Trimethoxysilane
from metal, at
plant/DE
1.06%
1.57 MJ
Electricity, medium
voltage,
production UCTE,
1.25%
0.0313 kg
MG-silicon, at
plant/NO S
1.65 MJ
Electricity, high
voltage,
production UCTE,
1.28%
0.848%
0.26 USD
Metal cutting and
forming machine
tool
0.685%
0.972 tkm
Transport, lorry
16-32t,
EURO4/RER S
0.87%
1.67 MJ
Electricity,
production mix
UCTE/UCTE U
1.28%
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Results for all the impact categories calculated using the selected ReCiPe methods are shown in Figure
11 for the cradle-to-gate life cycle of the refrigerator insulation, using cyclopentane as the blowing agent
and both conventional (on the left) and new (on the right) technologies. For all the impact categories,
the results have been normalized by the maximum value of the two, which for all categories is the
conventional. The specific maximum values for each impact category are (per refrigerator):
 Climate change (GWP): 19,80 kg CO2 eq
 Ozone depletion (ozone depletion potential, ODP):8.73e-7 kg CFC-11 eq
 Terrestrial acidification (acidification potential, or AP): 0.0737 kg SO 2 eq
 Freshwater eutrophication (eutrophication potential, or EPf: 0.018 kg P eq
 Marine eutrophication (eutrophication potential, or EPm): 0.00984 kg N eq
 Photochemical oxidant formation (photo oxidant creation potential, or POCP): 0.0637 kg
NMVOC (non-methane volatile organic carbon)
 Water depletion: 0.356 m3
 Fossil resource depletion: 9.08 kg oil eq
Figure 11: Selected cradle-to-gate ReCiPe categories per refrigerator
100
95
90
85
80
75
70
65
60
%
55
50
45
40
35
30
25
20
15
10
5
0
Climate change
Ozone depletio
n
Terrestrial
acidification
Freshwater
eutrophication
Refrigerator insulation, conventional PU foam/ RER U
Marine eutroph
ication
Photochemical
oxidant forma
Water depletio
n
Fossil depletion
Refrigerator insulation, new technology PU foam/ RER U
Comparing 1 p 'Refrigerator insulation, conventional PU foam/ RER U' with 1 p 'Refrigerator insulation, new technology PU foam/ RER U';
Method: Recipe Midpoint (H) V1.07 / World ReCiPe H / Characterization
In all cases, the values for the new technology were 3-7% less, based on the lower material use. Just as
electricity use dominated the cradle-to-grave results, the upstream burdens of the raw materials
dominate the cradle-to-gate results. Also, the differences in the specific impacts due to lower process
energy use were typically only about 1% of total differences in the impacts. Almost all the differences in
the cradle-to-gate impacts are due to difference in the material use, both in the amount (5% less in
total) and the compositions (different unit ratios and upstream burdens for each material). Although a
difference in potential impact of ~5% is often not significant in LCA, the dominance of a few inputs and
the high accuracy to which they are known suggests that the difference may be significant in this case.
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Toxicity
The result for cradle-to-grave toxicity impact potentials using the USETox method are shown in Figure
12. For all the impact categories, the results have been normalized by the maximum value of the two,
which is for all categories is the conventional. The specific maximum values for each impact category
are (per refrigerator over a 12 year life):
 Human toxicity, cancer: 5.81e-8 CTUh
 Human toxicity, non-cancer: 4.53e-7 CTUh
 Ecotoxicity: 0.559 CTUe
Figure 12: Cradle-to-grave USETox potential impacts per refrigerator
100
95
90
85
80
75
70
65
60
%
55
50
45
40
35
30
25
20
15
10
5
0
Human toxicity, cancer
Human toxicity, non-cancer
Refrigerator insulation, conventional PU foam w use and EOL/ RER U
Ecotoxicity
Refrigerator insulation, new technology PU foam w use EOL/ RER U
Comparing 1 p 'Refrigerator insulation, conventional PU foam w use and EOL/ RER U' with 1 p 'Refrigerator insulation, new technology PU foam w use EOL/ RER U';
Method: USEtox Recommended V1.01 / Characterization
The results in Figure 12 are presented separately from the ReCiPe results in Figure 8 due to the different
nature of toxicity impact potentials. Since the CF for the human toxicity metrics span more than 14
orders of magnitude and those for ecotox span more than 50, significant differences only exist when
they differ by at least one order of magnitude. This suggests that the differences of 10-14% shown in
Figure 11, despite being grounded on good information on a few key inputs, cannot be described as
being significant. There is not a significant difference in the toxicity potential impacts between these
options.
Although there is not a significant difference in between the scenarios in toxicity, there are some
interesting insights possible by looking at the contributions to them. Most of the toxicity impacts are
due to one of four inputs: UCTE low voltage grid electricity (for the use phase), EDTA (as a surrogate for
all the amine catalysts in the formulation), metal cutting & forming machine tool manufacturing (the EIO
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model for the production equipment), and disposal of polyurethane (end of life incineration), as shown
in Table 6 (blank cells are <0.5%).
Table 6: Percentage contributions to cradle-to-grave USETox potential impacts
Unit processes
UCTE electricity
EDTA
Disposal, PU
Equipment
Chemical emissions
Conventional foaming technology
Human tox, Human tox, Ecotox
Cancer
non-cancer
94.8
99.9
88.2
3.0
8.14
2.0
2.02
New foaming technology
Human tox, Human tox, Ecotox
Cancer
non-cancer
95.8
99.8
90.8
1.81
5.05
2.1
2.26
Formaldehyde
emissions in
EDTA model
and heavy oil
combustion;
dioxin in
incineration
model
Formaldehyde
emissions in
EDTA model
and heavy oil
combustion;
dioxin in
incineration
model
Carbon
disulfide
emissions in
copper
production
models
Formaldehyde
emissions in
EDTA;
chemical use
in power
right-of-way
and crops
(EIO)
Carbon
disulfide
emissions in
copper
production
models
Formaldehyde
emissions in
EDTA; chemical
use in power
right-of-way and
crops (EIO)
The calculated toxicity potential impacts show the very large contribution of small mass inputs,
sometimes very deep in the process models. For this study, examples are:
 Carbon disulfide emissions from copper processing, with copper being a significant part of
electricity production and distribution.
 Formaldehyde emissions from heavy fuel combustion used to generate electricity, calculated
from data on volatile organic carbon emissions and an assumed profile.
 Formaldehyde emissions from EDTA production, both to the air (for human toxicity, cancer) and
water (for ecotoxicity).
 Use of agricultural chemicals for right-of-way management for power lines in electricity
distribution, and in cotton, grain, and seed oil farming which enter in through the economy-wide
model used for equipment production.
Each of these examples shows that the strength and weakness of LCA is related to the quality and
consistency of background data and LCIA models. The strength is that in principle one can find surprising
and quite likely real impacts for things occurring far back in supply chains. The weakness is that
sometimes impacts and emissions are not known in the same degree of detail or other impacts or
emissions are so small and specific, they quite possibly may not have occurred in many specific supply
chains (such as those that enter via the EIO model).
It is also somewhat concerning that although the process-based LCA for EDTA in ecoinvent includes
estimated formaldehyde emissions, there are almost none in the one for MDI, which has formaldehyde
as a key raw ingredient. Although this might be due to the existence of excellent process control, it is
also quite possibly due to formaldehyde emissions being below a mass-based cutoff or included as
simply volatile organic compounds (VOC) or non-methane volatile organic compounds (NMVOC) in the
former APME/PlasticsEurope data collection (as the actual PlasticsEurope/ISOPA eco-profiles report
formaldehyde emissions).
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The value in looking at toxicity results is that it brings up possible issues of concern that might not be
otherwise considered.
Uncertainty and sensitivity analyses
The bills of material used to describe the production mass inputs are very accurate and representative
of the formulations used for the two technologies. The process models for these inputs were taken
from ecoinvent, and so may not be fully representative of a specific supply chain. The impact of this
uncertainty was investigated by changing the production inputs by +50%. This change affected the
ReCiPe impacts by less than 1%, human toxicity by less than 2% and ecotoxicity less than 6%. Use phase
electricity demand is dominant. Although specific data of specific supply chains may significantly
influence isolated impacts due to very specific emissions, it is very unlikely that the overall conclusion of
the beneficial use phase patterns of the new technology are significantly influenced due to this potential
uncertainty. The same is true for the potential future correction or updating of impact and toxicology
models and characterization factors.
The use phase burdens were calculated based on the average EU “A” performance of the refrigerator for
12 years using UCTE low voltage electricity. The range of A performance is from 263 to 344 kWh/year, a
range of +13% from the average. As shown earlier, use of the average A performance showed that the
use phase could contribute between 97.79% and 99.91% of the selected ReCiPe potential impacts and
88.2% to 99.8% of the USETox potential impacts. Using the full performance range for class A expanded
this range only slightly: the use phase could contribute between 97.68% and 99.92% of the selected
ReCiPe potential impacts and 86.6% to 99.9% of the USETox potential impacts. The specific
performance of an A class refrigerator would not affect the conclusion that electricity consumption
during the use phase of a refrigerator is the dominant source of potential environmental impacts.
In the cradle-to-grave results, the potential impacts due to the end of life treatment were of the same
order of magnitude as those due to the production impacts, although much smaller than those from the
use phase. The end of life option used in the results presented above was that of incineration, using a
model from ecoinvent for polyurethane foam insulation (neglecting the parts of the refrigerator not
within the project scope boundaries). An implicit assumption in using this model is that all of the
blowing agent is incinerated along with the rest of the foam, and the carbon in it is ultimately emitted as
CO2. It is possible that some blowing agent is emitted during the disassembly and shredding of the
refrigerator. As a “worst case” for this sensitivity analysis, we assumed all the blowing agent was
emitted directly to the atmosphere.
Making these input changes did not make any significant (>0.04%) changes in any cradle-to-grave ReCiPe
impact category, nor any significant (>0.15%) changes in any USETox impact category. On a cradle-tograve basis but excluding the use phase electricity use, the potential impacts were still all negligible
(<0.5%) or small (1% decrease in POCP, 2% decreases in EPm, GWP and human toxicity (cancer)). With
the exception of USETox ecotoxicity, the small changes that did occur were based only on the reduced
amount of mass incinerated; cylcopentane as an emission to air is an input to only the USETox
ecotoxicity metric of all the metrics considered in this study. The impact of cyclopentane emissions is
not covered well by the impact assessment methods chosen.
Another assumption considered in the sensitivity analysis was the “allocation” of 100% of the use-phase
burdens to the insulation technology. Although the quality of the insulation is perhaps the most
important technology that enables high-efficiency refrigerators to perform well, many other aspects of
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the design and construction also have an impact (compressor design, control systems, etc.). For the
sensitivity calculations we assumed, arbitrarily, to include 50% of the burdens from the use phase as the
part influence by insulation technology. As described earlier, “allocation” of 100% of the use-phase
burdens showed that the use phase could contribute between 97.79% and 99.91% of the selected
ReCiPe potential impacts and 88.2% to 99.8% of the USETox potential impacts. Using only 50% changes
this range only slightly: the use phase could contribute between 95.68% and 99.82% of the selected
ReCiPe potential impacts and 78.7% to 99.7% of the USETox potential impacts. Allocation of as low as
50% of the use phase burdens would not affect the conclusion that electricity consumption during the
use phase of a refrigerator is the dominant source of potential environmental impacts.
Data quality assessment
Overall, the data used in this study, a combination of Dow laboratory and production data, ENERG-ICE
collaboration pilot plant data, and Ecoinvent library data, allowed the construction of life cycle models
that well describe the production of polyurethane foam insulation using conventional and new
technology. Primary data were obtained for the most critical inputs – the compositions of the two
polyurethane insulations and the performance characteristics of the foams. These are data of high
quality since they come from direct laboratory, pilot plant and operation measurements and
measurement systems. Secondary data, from Ecoinvent 2.2 were used for upstream process models to
provide an established, documented and reasonable source of information.
Despite the fact that the used datasets for Polyols and Isocyanate show considerably higher values for
certain impacts compared to the latest datasets published by industry associations [42, 43], it does not
influence the conclusions. The upstream data quality is not decisive.
CONCLUSIONS
This study includes models for the complete production process in Europe for two specific polyurethane
foams for use in a Class A residential refrigerator, and included all life cycle stages. It is limited to these
foams, and in particular to the use of cyclopentane as a blowing agent. The study did not include other
aspects of the refrigerator design or use that could impact performance.
Electricity consumption during the use phase of a refrigerator is the dominant source of potential
environmental impacts. Use of insulation with improved performance is a way to reduce burdens from
use of refrigerators. The new technology allows for a measured 10% less electricity use (all other things
remaining the same) which translates to about 10% reduction in all potential cradle-to-grave impacts.
Due to the dominance of the use phase, uncertainty about specific production or end-of-life inputs,
including the choices of background data sets, would not have a significant impact on the results.
On a cradle-to-gate perspective, the new technology offers a small but plausible advantage in all impacts
considered, primarily due to the less mass required to get the same performance. The benefit of
reduction in heat and power to the process was small compared to the benefit from the reduced mass.
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RECOMMENDATIONS/FUTURE WORK
If this work is extended to geographies outside of Europe, it would be necessary to get or estimate data
for the production of other blowing agents, such as HFC245fa, which were not part of this project’s
scope.
CRITICAL REVIEW
A critical peer review was conducted by Dr. Martin Baitz of PE INTERNATIONAL AG. The final review
letter is given in the Appendix
ACKNOWLEDGMENTS
The authors thank Renato Paludetto and Thorsten Kuethe for their support of this project and helpful
discussions on the project scope, and Eng. Maurizio Corti (Technical Director of Afros-Cannon) and his
team for production equipment design and operation data.
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APPENDIX
Critical review letter
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4. Curran, M. A., “Life Cycle Assessment: Principles and Practice”, Scientific Applications International
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5. Life Cycle Assessment Handbook, Mary Ann Curran, editor, Scrivener Publishing (2012)
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