comparati ve life cycle assessment of walid technologies ... · the study contained in this...

The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 309985

www.eu-walid.com

Comparati ve Life Cycle Assessment of WALiD

Technologies and Processes Handbook

First published in 2017 by

Smithers Rapra and Smithers Pira LtdShawbury, Shrewsbury, UK, SY4 4NR

© Smithers Rapra and Smithers Pira Ltd., 2017

All rights reserved. Except as permitted under current legislation no part of this publication may be photocopied, reproduced or distributed in any form of by any means or stored in a database or

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Every effort has been made to contact copyright holders of any material reproduced within the text and the author and publishers apologise if any have been overlooked.

Typeset by S. Hall Typesetting & Graphic Design

Comparati ve Life Cycle Assessment of WALiD Technologies and Processes Handbook

Contents

1. Introduction 11.1 WALiD Blade 1

1.1.1 Blade Root 2

1.1.2 Blade Tip 2

1.1.3 Shell Core 3

1.1.4 Shear Web 3

1.1.5 Spar Cap 3

1.1.6 Coati ng 4

2. Goal and Scope of the Study 52.1 Goal of the Study 5

2.2 Scope of the Study 5

2.2.1 Functi onal Unit 5

2.2.2 System Boundaries 6

2.3 Impact Assessment Method 7

2.3.1 Midpoint Level 7

2.3.2 Endpoint Level 9

3. Life Cycle Assessment - Materials 103.1 Blade Root 10

3.2 Blade Tip 11

3.3 Shell Core 12

3.4 Shear Web 14

3.5 Spar Cap 15

3.6 Coati ng 16

3.7 Whole Blade 17

3.7.1 Midpoint Analysis 17

3.7.2 Endpoint Analysis 18

3.7.3 Global Warming Potenti al 19

4. End of Life 214.1 Powder Impression Moulding (PIM) 21

4.2 Retaining Walls 22


4.3 3D Printi ng 24

4.4 Decking 25

4.5 Railway Sleepers 26

4.6 Use of Existi ng Blade Structure 27

4.7 Future Recommendati ons 27

5. Conclusions and Recommendations 29

References 30

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Introduction

Security, sustainability and economic prosperity are together the energy trilemma that we face (Internati onal Energy Agency, 2014). The use of new and renewable energy sources and the development of cleaner and effi cient energy technologies will play an important role in solving this trilemma. Over recent years, renewable energy sources have achieved greater signifi cance as a part of the energy mix for the major EU economies. Among these renewable energy sources, wind power is currently one of the fastest-growing sources of electricity globally (Internati onal Energy Agency, 2016).

Amongst wind power installati ons, the most producti ve installati ons (measured by average number of hours of operati on at full capacity) are those which are installed off shore. The NEEDS (Dong Energy, 2008) project compared annual producti on of the same 2MW turbine installed in an off shore and onshore wind farm. Electricity producti on (in MWh.yr) of the off shore installati on was 8088, compared with the onshore installati on of 5634. This equates to a 43% producti vity benefi t for an off shore installati on. Further, the historic success of onshore wind energy has led to a shortage of suitable land sites in many parts of Europe.

Europe conti nues to dominate the off shore wind sector and approximately 90% of global capacity is within Europe. As of 30 June 2016, there are 3344 off shore wind turbines with a combined capacity of 11538 MW fully grid connected in European waters in 82 wind farms across 11 countries (Wind Europe, 2016). A report by the European Wind Energy Associati on (EWEA) (EWEA, 2015) predicts three wind energy scenarios for 2030, showing the expected growth in off shore wind energy. The low, central and high scenarios expect 7439, 11081 and 16346 off shore wind turbines to be installed in Europe by 2030 respecti vely.

Wind energy is a clean technology during its operati onal phase as it generates electricity from a renewable source without producing any waste or using any mineral or water resources. However, in a life cycle perspecti ve there are non-renewable resource demands and harmful emissions associated with it. These environmental and resource pressures can be quanti fi ed and assessed by the method of life cycle assessment (LCA).

The study contained in this handbook uses LCA to examine, in detail, the diff erences in life cycle impact between a current state of the art off shore wind blade and the newly designed WALiD blade.

1.1 WALiD Blade

The power generated by off shore wind turbines is dependent on the rotor plane area of the blade. The major issue is that due to the weight of larger blades, the materials used suff er considerable strain, which reduces the amount of ti me they are operati onal. Additi onally, the blades have to be adapted to more challenging environmental off -shore conditi ons such as corrosive and humid environments with high temperature variati ons and high load conditi ons. Using current state of the art materials these limits cannot be overcome.

The WALiD project has combined process, material and design innovati ons in an integrated approach. The core innovati on aimed to use advanced thermoplasti c composites. This creates cost-eff ecti ve,

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lightweight, durable and recyclable 90m off shore blades with benefi cial weight/performance rati o, making wind energy more aff ordable and competi ti ve.

As in conventi onal blade design, the main structural components are the upper and lower shells that are connected to each other at the leading and trailing edge. Inside, two shear webs keep the shells at the designated distance. To achieve an appropriate bending sti ff ness spar caps are uti lised in both shells. Finally, the whole blade is covered by a coati ng to protect the blade from environmental infl uences.

1.1.1 Blade Root

Figure 1: Blade root and ti p

The blade root is the part of the blade which bears the highest loads and makes up a high proporti on of the weight. The main functi on of the blade root is the transmission of the load from the blade to the hub. The connecti on concept determines the way the load is transferred between the composite structure of the blade and the metallic structure of the hub.

State of the art blades are commonly constructed using thermoset materials and fi xed to the hub with a T-bolt connecti on. As the blade root connecti on needs to be reliable throughout the whole lifeti me of the blade, high safety factors are taken into account. This leads to wall thicknesses of up to 160mm in the laminate structure, which results in an additi onal weight of the blade root.

By reducing the wall thickness of the laminate in the root secti on it is possible to reduce the weight and the required composite materials of the blade root. A novel blade root concept using thermoplasti c material has been developed within the WALiD project which achieves this without aff ecti ng the transfer of the required loads.

The idea is to use a steel insert with a waved curvature, which is directly connected to the hub. Tapes have been produced with mechanical properti es beyond the current state of the art. Hybrid yarns are used as raw material for tape producti on and trials have been carried out on the adhesion of the polymers and fi bres. During the process the tapes are heated on a pultrusion line to melt temperature and then positi oned in a defi ned layer to obtain the best adhesion of fi bres and polymer. They are then processed and cooled to fuse the layers together before being wound onto a reel. These unidirecti onal thermoplasti c tapes are directly placed on the metal insert using an automated fi bre placement process and fi xed by thermoplasti c belts. The belts also consist of unidirecti onal tapes. The new connecti on concept makes it possible to transfer the load from the blade to the hub without the need of a bolt connecti on. This, in turn, allows a reducti on of the laminate thickness in the root secti on as the conti nuous fi bre structure is not locally damaged by drilling holes into the laminate.

1.1.2 Blade Tip

The blade ti p, as the part which is furthest away from the hub, has to withstand parti cular mechanical requirements. The high rotati onal speed of a wind turbine blade ti p leads to high mechanical stresses.

Initi al discussions about improvements to the blade ti p concluded that in contrast to state of the art ti p secti ons of blades, the developed blade ti p within this project will consist of a tailored composite structure made from thermoplasti c tapes. The tape lay-up in the automated fi bre placement (AFP)

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process enables a tailored design according to the load requirements of the blade ti p. This allows the exploitati on of the lightweight constructi on potenti al in the ti p area of the blade, which is of high importance as a reducti on in weight of parts sited away from the hub decreases the stress in the whole blade structure.

1.1.3 Shell Core

Figure 2: Shell core

For the shell core, new modifi ed thermoplasti c polymer blends were used to produce tailored properti es for the foamed material. In additi on, new polymers and additi ves for polymeric foams in a conti nuous extrusion process were investi gated and the materials characterised. This has led to new ultra-light and sti ff foam materials produced using a cost-eff ecti ve manufacturing process.

1.1.4 Shear Web

Figure 3: Shear web

The purpose of the shear web is to keep the geometrical distance between the spar caps, ensuring the overall bending sti ff ness of the blade.

Currently, wind blades are manufactured using glass fi bre and/or carbon fi bre reinforced thermosets, balsa wood and PVC foams. Processes used include wet hand layup, thermoset impregnated fi lament winding, prepreg technology and resin infusion technology. There are a number of disadvantages to these processes including the emission of volati le organics during processing, long cycle ti mes due to the curing process, poor resistance against environmental conditi ons resulti ng in a decrease of mechanical properti es, an increase in weight and a lack of reproducibility and recyclability.

WALiD has developed a new lightweight design for the shear web connecti ng the two outer shells of the wind blade and has replaced the thermoset materials with a framework of new materials. These new materials consist of thermoplasti c composites and foams which are processed using automated fi bre placement and winding.

The thermoplasti c materials used are cost-eff ecti ve and have a high level of recyclability. Also, the use of foam has been opti mised to reduce scrap.

1.1.5 Spar Cap

Currently, spar caps are manufactured with reinforcement fi bres and thermoset materials such as epoxy, vinyl ester and thermoset polyester and are manufactured using resin infusion technology or consolidati on of prepreg systems.

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WALiD has developed a new concept to produce the spar caps. Automated fi bre placement is carried out using a specially adapted robot. Unidirecti onal tapes and thermoplasti c materials have been used in order to give strength, sti ff ness and rigidity to the structure and reduce weight.

1.1.6 Coating

Figure 4: Coati ng

Off shore wind turbines operate under harsh conditi ons and are subject to abrasion, fouling, ice and in parti cular, erosion of the leading edge by droplet impingement wear. The thermoset coati ngs used in state of the art blades are diffi cult to recycle and are not lightweight.

WALiD has developed a reinforced thermoplasti c coati ng with anti -icing properti es and durability against abrasion to improve environmental resistance, which can lead to reduced maintenance costs.

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2.1 Goal of the Study

The move towards sustainable development requires a paradigm shift from a fractured view of the environment, with the emphasis on one stage of the life cycle, to a more holisti c life cycle approach to environmental management. LCA is a tool that enables and supports such a paradigm shift as it embodies life cycle thinking and so provides a full picture of human interacti on with the environment.

The applicati on of this LCA study is the comparison of the overall environmental impacts associated with the new thermoplasti c based technologies developed within the WALiD project with equivalent wind turbine blades based on current technology.

The blade developed in the WALiD project was designed to be 90m in length. Therefore, to allow a comparison to take place, the inputs and outputs of the current state of the art wind blade that is studied in this LCA have been scaled up to represent a 90m blade. In this handbook, “#2-Blade” refers to #2-Blade with Carbon Spar-Cap and “#3-WALiD Blade” refers to the blade developed in the WALiD project.

By identi fying the steps within the life cycle which have the most signifi cant impact on the environment, environmental management eff orts can be directed eff ecti vely. The early results from the screening analysis were used by the consorti um to inform the material selecti on process, and to evaluate and miti gate environmental impact hotspots of the thermoplasti c materials approach, compared to the traditi onal and almost universally adopted use of epoxy based thermosetti ng materials.

The Internati onal Standards ISO 14040/44 provides an indispensable framework for life cycle assessment. These standards, in conjuncti on with the best practi ce as described in the Internati onal Reference Life Cycle Data System (European Commission JRC Insti tute for Environment and Sustainability, 2010) were used to guide all analyses conducted as part of the WALiD LCA acti viti es.

2.2 Scope of the Study

2.2.1 Functional Unit

The functi onal unit of 1 kw/h, delivered to the grid will be used.

The functi on of any power generati on plant is to generate electricity. Hence the functi onal unit should be an amount of generated electricity.

The operati onal lifeti me of 25 years will be used.

This is longer than the 20 year lifeti me used for most existi ng LCA studies. A longer lifeti me of 25 years is refl ecti ve of the experience of Vestas. The Danish company has the largest market share of any turbine maker, and began manufacturing industrial scale turbines in 1979. Vestas’ experience is that operati onal lives in excess of 30 years are regularly achieved. Further to this, for the type of investment and installati on cost, the larger off shore turbines should be expected to have a longer lifeti me.

Goal and Scope of the Study

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2.2.2 System Boundaries

In this study, the cradle-to-grave life cycles of the wind turbine blades were to be investi gated. The cradle-to-grave approach evaluates all stages of the wind blade’s life from raw material producti on to end of life management. Energy and material inputs are traced back to the extracti on of resources, and emissions and wastes from each life cycle stage are quanti fi ed. The result is a life cycle inventory (LCI). The LCA evaluates all stages of the blade’s life from the perspecti ve that they are interdependent, meaning that one operati on leads to the next. The system boundaries in this LCA are presented in Figure 5 and the stages are as follows:

• Materials

This stage comprises the raw material producti on and supply of other components that are delivered in their various forms to the factory where the blades are manufactured. Any alterati on of the raw materials will be considered in this step, for example, additi on of nanomaterials to polymers, forming of unidirecti onal composite tapes, producti on of polymeric foams, and the manufacture of coati ngs will be included within this stage of the LCA.

• Blade manufacture

This step includes the materials preparati on and assembly, integrati on of the blade to the hub fi xings, and applicati on of the coati ng to form a fi nished blade.

• Transport and installati on

This stage takes into account the transfer of the fi nished components from their various places of manufacture to the wind farm site, and their placement and fi xing into their place in the wind turbine structure.

• Operati on

The operati on phase deals with the general running and maintenance of the blades as the turbines generate electricity during their 25 year lifeti me.

• Dismantling

The decommissioning (or repowering) of the wind farm, and the return of the dismantled components to shore.

• Recycling or end of life disposal of the components.

Figure 5: Illustrati on of system boundaries

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The analysis in this LCA study focuses on the materials stage of the life cycle. This is due to a lack of data for the other stages. End of life opti ons have been investi gated and are presented in this handbook in chapter 4.

2.3 Impact Assessment Method

A life cycle inventory has been developed to demonstrate a complete map of all inputs and outputs of the WALiD wind blade. SimaPro soft ware was used as the principal evaluati on tool for the calculati on of the environmental impacts. The current editi on being used at Smithers Rapra is 8.0.2. To make it possible to successfully compare blades using diff erent materials and processes, all the data has been obtained by asking partners within the consorti um, the industry or seeking informati on on scienti fi c publicati ons, LCA reports and datasheet of materials. Some data is used from the Ecoinvent database. The Ecoinvent database was selected to provide background data to esti mate quanti ti es of inputs and outputs for diff erent unit processes within the system. The database is used extensively by LCA practi ti oners throughout Europe.

The impact assessment method ReCiPe was employed in this study to transform the long list of consumed resources and emissions into impact category indicators. The results obtained in the classifi cati on phase are multi plied by the characterisati on factors of each substance within each impact category. These indicator scores express the relati ve severity on an environmental impact category. It integrates and harmonises in a consistent framework:

• Eighteen midpoint indicators

• Three endpoint indicators

2.3.1 Midpoint Level

Midpoint impact category, or problem-orientated approach, translates impacts into environmental themes (this LCA uses the Hierarchist perspecti ve):

• Climate Change

Climate change can result in adverse eff ects upon ecosystem health, human health and material welfare. Climate change is related to emissions of greenhouse gases to air. Gases contributi ng to the greenhouse eff ect are aggregated according to their impact on radiati ve warming compared to carbon dioxide as the reference. Therefore, impacts are expressed in kg CO₂ equivalents.

• Ozone Depleti on

The characterisati on factor for ozone layer depleti on accounts for the destructi on of the stratospheric ozone layer by anthropogenic emissions of ozone depleti ng substances (ODS). Impacts are expressed as kg CFC-11 equivalents.

• Terrestrial Acidifi cati on

Terrestrial acidifi cati on is characterised by changes in soil chemical properti es following the depositi on of nutrients (namely, nitrogen and sulphur) in acidifying forms. Acidifi cati on potenti al is expressed as kg SO₂ equivalents.

• Freshwater Eutrophicati on

The characterisati on factor of freshwater eutrophicati on accounts for the environmental persistence of the emission of phosphorous (P) containing nutrients. The unit is kg P to freshwater equivalents.

• Marine Eutrophicati on

The characterisati on factor of marine eutrophicati on accounts for the environmental persistence of the emission of nitrogen (N) containing nutrients. The unit is kg N to freshwater equivalents.

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• Human Toxicity

This category concerns eff ects of toxic substances on the human environment. Human Toxicity Potenti als (HTP) are expressed as kg 1,4-DB (dichlorobenzene) equivalent.

• Photochemical Oxidant Formati on

Photochemical oxidant formati on is the formati on of reacti ve substances (mainly ozone) which are injurious to human health and ecosystems and which also may damage crops. The characterisati on factor of photochemical oxidant formati on is defi ned as the marginal change in the 24h-average European concentrati on of ozone due to a marginal change in emission of substance x. The unit is kg NMVOC.

• Parti culate Matt er Formati on

The characterisati on factor of parti culate matt er formati on is the intake fracti on of PM₁₀. The unit is kg PM₁₀ equivalents.

• Terrestrial Ecotoxicity

This category refers to impacts of toxic substances on terrestrial ecosystems, as a result of emissions of toxic substances to air, water and soil. The unit is kg 1,4-DB equivalents.

• Freshwater Ecotoxicity

This category refers to impacts of toxic substances on freshwater ecosystems, as a result of emissions of toxic substances to air, water and soil. The unit is kg 1,4-DB equivalents.

• Marine Ecotoxicity

This category refers to impacts of toxic substances on marine ecosystems, as a result of emissions of toxic substances to air, water and soil. The unit is kg 1,4-DB equivalents.

• Ionising Radiati on

The characterisati on factor of ionizing radiati on accounts for the level of exposure. The unit is kg Uranium-235 (U-235) equivalents.

• Agricultural Land Occupati on

The amount of agricultural land occupied for a certain ti me. The unit is m²a.

• Urban Land Occupati on

The amount of urban land occupied for a certain ti me. The unit is m²a.

• Natural Land Transformati on

The amount of natural land transformed and occupied for a certain ti me. The unit is m².

• Water Depleti on

The factor for water depleti on is water consumpti on. The unit is m³.

• Metal Depleti on

This impact category is concerned with protecti on of human welfare, human health and ecosystem health. The characterisati on factor for metal depleti on is the decrease in grade. The unit is kg Iron (Fe) equivalents.

• Fossil Depleti on

This impact category is concerned with protecti on of human welfare, human health and ecosystem health. This impact category indicator is related to extracti on of fossil fuels due to inputs in the system. The unit is kg oil equivalents.

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2.3.2 Endpoint Level

Endpoint impact category, also known as the damage-orientated approach, translates environmental impacts into three issues of concern:

• Human Health: Eff ect of environmental changes to human health expressed as the number of years of life lost and the number of years lived disabled. These are combined and measured in Disability-Adjusted Life Years (DALYS).

• Ecosystems: Expressed as the loss of species over a certain area, during a certain ti me. The unit is years.

• Resources: Expressed as the surplus costs of future resource producti on over an infi niti ve ti meframe (assuming constant annual producti on), considering a 3% discount rate. The unit is 2000US$.

These three endpoint categories are weighted using the ReCiPe endpoint assessment method with hierarchist weighti ng to generate single-score values expressed in kpt (thousands of eco-points) for average yearly impact of one European citi zen.

In this study, both midpoint and endpoint assessments have been conducted. Figure 6 shows the relati onship between midpoint and endpoint indicators and where the single score results are coming from.

Figure 6: Relati onship between LCI parameters (left ), midpoint indicator (middle) and endpoint indicator (right) (Source: Goedkoop et al, 2008).

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This chapter shows the impact assessment results for the materials stage of the life cycle. Results in this chapter will show comparisons between the two blades in six components; the blade root, blade ti p, shell core, shear web, spar cap and the coati ng, and also the blade as a whole.

3.1 Blade Root

As the WALiD blade root has a new design and concept it is interesti ng to observe its impact compared to the current concept.

Table 1 shows the characterised results from the midpoint method. The #3-WALiD Blade has higher potenti al environmental impacts across 10 of the 18 indicators compared to the #2-Blade. In the #3-WALiD Blade root the quanti ty of metals used is six ti mes higher than in the #2-Blade because of the metal insert. This explains why the impact category metal depleti on is far greater for the #3-WALiD Blade.

Table 1: Characterised results of the root (midpoint method)Impact category Unit #2-Blade with Carbon

spar cap#3-WALiD Blade

Climate change kg CO₂ eq 69830.507 51925.386

Ozone depleti on kg CFC-11 eq 0.003 0.004

Terrestrial acidifi cati on kg SO₂ eq 389.074 242.809

Freshwater eutrophicati on kg P eq 1.658 2.255

Marine eutrophicati on kg N eq 13.534 6.734

Human toxicity kg 1,4-DB eq 23824.079 20896.874

Photochemical oxidant formati on kg NMVOC 355.087 177.095

Parti culate matt er formati on kg PM₁₀ eq 183.711 111.947

Terrestrial ecotoxicity kg 1,4-DB eq 3.712 4.317

Freshwater ecotoxicity kg 1,4-DB eq 19.663 10.780

Marine ecotoxicity kg 1,4-DB eq 41.428 82.296

Ionising radiati on kBq U-235 eq 9740.449 12818.604

Agricultural land occupati on m²a 331.851 688.808

Urban land occupati on m²a 181.116 323.918

Natural land transformati on m² 5.930 8.081

Water depleti on m³ 131949.306 328813.549

Metal depleti on kg Fe eq 6289.014 28614.577

Fossil depleti on kg oil eq 24387.420 19607.888

Figure 7 shows the potenti al impacts of the two blade roots at the endpoint level. It shows no great diff erences between the two blades overall, however there is a higher potenti al impact on human health and ecosystems from the #2-Blade and higher impacts on resources from the #3-WALiD Blade. This higher impact on resources is because of the metal insert as explained previously.

Life Cycle Assessment - Materials

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Figure 7: Comparison of the root (endpoint method)

3.2 Blade Tip

Table 2: Characterised results of the ti p (midpoint method)

Impact category Unit#2-Blade with

Carbon spar cap#3-WALiD Blade



















As shown in Table 2, blades with thermoplasti c tapes (#3-WALiD Blade) rather than thermoset materials (#2-Blade) in the ti p provide lower potenti al environmental impacts for 11 of the 18 midpoint impact categories.

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Figure 8 presents the potenti al environmental impacts of the two blade ti ps at the endpoint level. The potenti al impacts on all three categories of resources, ecosystems and human health are lower for the #3-WALiD blade.

Figure 8: Comparison of the ti p (endpoint method)

3.3 Shell Core

Table 3 shows the potenti al environmental impacts at the midpoint level of the shells for the two comparing blades. The potenti al environmental impacts of 13 of the 18 categories are higher for the #2-Blade than the #3-WALiD Blade.

Figure 9 shows the potenti al environmental impacts of the shell core of the two blades at the endpoint level. The diff erence between the material inputs in the ti p and the shell of the #3-WALiD Blade is the additi on of foam in these data. By comparison to Figure 8, Figure 9 confi rms that the foam does not contribute greatly to a diff erence in the proporti on of the potenti al endpoint impacts. The shell of the #3-WALiD Blade has lower potenti al environmental impacts than the shell of the #2-Blade at the endpoint level. The greatest reducti on from the WALiD blade at this level is human health. All the midpoint indicators that contribute to human health endpoint category have higher potenti al impacts from the #2-Blade.

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Table 3: Characterised results of the shell (midpoint method)

Impact category Unit #2-Blade with Carbon spar cap

#3-WALiD Blade



















Figure 9: Comparison of the shell (endpoint method)

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3.4 Shear Web

Table 4 shows the potenti al environmental impacts at the midpoint level for the shear web of the two blades. It shows there are the same number of midpoint categories with higher potenti al impact from both the #2-Blade and the #3-WALiD Blade. However, the endpoint results presented below in Figure 10 show how these impacts can contribute to resources, ecosystems and human health.

Table 4: Characterised results of the shear web (midpoint method)Impact category Unit #2-Blade with




















Figure 10: Comparison of the shear web (endpoint method)

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Compared to the ti p and the shell, the shear web is made of tapes, foams and glue. By comparing with Figure 8 and Figure 9, Figure 10 shows the additi on of glue does not contribute greatly to a diff erence in the proporti on of the potenti al impacts.

The potenti al environmental impact on all three endpoint categories is lower for the #3-WALiD Blade than the #2-Blade. All midpoint indicators that contribute to the concern of human health have a lower potenti al impact for the #3-WALiD Blade. Lower potenti al impacts are achieved for the midpoint categories of climate change, terrestrial acidifi cati on and freshwater ecotoxicity for the WALiD blade. These have contributed to a lower potenti al environmental impact on ecosystems. The higher fossil depleti on of the #2-Blade has caused the higher impact on resources for this blade.

3.5 Spar Cap

Table 5 presents the characterised results comparing the potenti al environmental impacts of the spar cap for the #2-Blade and the #3-WALiD Blade at the midpoint level. The #3-WALiD Blade is shown to lead to lower potenti al impact across 12 of the 18 indicators.

Table 5: Characterised results of the spar cap (midpoint method)

Impact category Unit #2-Blade with Carbon spar cap

#3-WALiD Blade



















Figure 11 shows the potenti al environmental impacts of the spar cap of the two blades at the endpoint level. As can be seen in Figure 11, the choice of thermoplasti c material in the spar cap achieves a decrease in the overall environmental impacts when compared to the material in current state of the art blades. The tapes in the spar cap of the #3-WALiD blade are made of diff erent thermoplasti c fi bres to those in the ti p. Figure 11 displays the diff erences between the potenti al impacts of the spar cap and the ti p when compared with Figure 8.

As with the ti p and the shell, all midpoint categories that contribute to impacts on human health have higher potenti al impacts for the #2-Blade.

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Figure 11: Comparison of the spar cap (endpoint method)

3.6 Coating

Table 6 shows the characterised results of the coati ng of the two blades under study at the midpoint level. The coati ng of the WALiD blade is the only part which does not contain similar materials to the parts described above. The thermoplasti c coati ng in the WALiD blade provides the lowest potenti al environmental impact for 15 of the 18 midpoint impact categories compared with current materials in the #2-Blade.

Table 6: Characterised results of the coati ng (midpoint method)Impact category Unit #2-Blade with




















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Figure 12 shows a large diff erence between the potenti al impacts of the coati ng of the two blades at the endpoint level. It is possible to observe that each endpoint category (resources, ecosystems and human health) of the #3-WALiD Blade has only one third of the impact of the #2-Blade. All midpoint indicators that lead to the endpoint categories of human health and resources have a higher potenti al environmental impact from the #2-Blade.

Figure 12: Comparison of the coati ng (endpoint method)

3.7 Whole Blade

This chapter provides an analysis of the LCA results for the materials stage taking into account all data from the two blades.

3.7.1 Midpoint Analysis

Table 7 shows the characterised results of the two blades at the midpoint level. The #3-WALiD Blade provides lower potenti al environmental impact across 12 of the 18 midpoint impact categories compared to the #2-Blade.

Figure 13 shows 12 of 18 categories have 100% of impact for the #2-Blade compared to the #3-WALiD Blade. The six categories at 100% for the #3-WALiD Blade are freshwater eutrophicati on, agricultural land occupati on, urban land occupati on, natural land transformati on, water depleti on and metal depleti on. All of these categories menti oned are related to land, agriculture and water except for metal depleti on, which is due to the insert. The other categories have been related to the “Ester family”. Some of these polymers are biodegradables and may have impact on the environment at the end of life.

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Table 7: Characterised results of the two blades (midpoint method)Impact category Unit #2-Blade with




















Figure 13: Comparison of the two blades (midpoint method)

3.7.2 Endpoint Analysis

Table 8 and Figure 14 show the potenti al environmental impacts of the #2-Blade and the #3-WALiD blade at the endpoint level.

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Table 8 and Figure 14 both show the lower impact of the #3-WALiD Blade compared to the #2-Blade. Even though the #3-WALiD Blade has a much more accurate database, the impact is sti ll lower than the #2-Blade. These midpoint and endpoint results show that using the materials and processes developed in the WALiD project minimises the potenti al environmental impact on resources, ecosystems and human health at the materials stage compared to current state of the art.

Table 8: Characterised results of the two blades (endpoint method)Label Human Health Ecosystems Resources

#2 – 90m Blade with Carbon Spar-Cap combined

17.661 8.325 18.127

#3 90m WALiD Blade 12.273 6.251 15.618

Figure 14: Comparison of the two blades (endpoint method)

3.7.3 Global Warming Potential

When determining the climati c impact of a substance, the Global Warming Potenti al (GWP) is used. This is a measure of the eff ect on radiati on of a parti cular quanti ty of the substance over ti me relati ve to that of the same quanti ty of CO₂. The GWP depends thus on the ti me spent in the atmosphere by the gas, and on the gas’s capacity to aff ect radiati on, which describes the immediate eff ects on overall radiati on of a rise in concentrati on of the gas. The GWP is calculated with combined climati c and chemical models and covers two eff ects: the direct eff ect a substance has through the absorpti on of infrared radiati on and the indirect chemical eff ects on overall radiati on.

The GWP of the #2-Blade and the #3-WALiD Blade has been analysed for the materials life cycle stage. Figure 15 and Figure 16 display the network of the GWP for each blade which shows where the impacts are coming from.

Figure 15: Network of the Global Warming potenti al of the #2-Blade

Figure 15 shows that 83% of the impact from the #2-Blade is from carbon fi bre (56.2%) and epoxy resin (27.2%). Carbon fi bre has a very high impact compared to glass fi bre.

Figure 16: Network of the Global Warming potenti al of the #3-WALiD Blade

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From Figure 15 and Figure 16 a comparison can be made between the materials contributi ng to GWP in the two blades. The diff erence in materials and their contributi on to GWP for the #2-Blade and the #3-WALiD Blade are as follows; “epoxy resin” (27.2%) and “thermoplasti c 1” (17%), “gel coat” (1.11%) and “coati ng” (0.66%), “PVC foam- Divinycell” (3.36%) and “foam” (1.49%), but mostly the impact is coming from the fi bres: “carbon fi bre” (56.2%) and “fi bre 2” (64.1%) respecti vely.

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This handbook has highlighted the growth in the European wind industry, in terms of both the number of turbines and their sizes. In additi on, a growing number of wind turbines are to be decommissioned, due to the fact that the lifeti me of a wind turbine is approximately 20-25 years and there are increased opportuniti es for replacing old models with newer and more effi cient machines.

Therefore, a sustainable process to deal with the turbines at the end of their life is needed in order to maximise the environmental benefi ts of wind energy through a lifecycle approach. Most parts of a wind turbine such as foundati on, tower, components of the gear box and generator are already recyclable and treated accordingly with an average recyclability for a wind turbine between 80 to 85%. However, wind blades represent a challenge for waste management due to the complexity of their compositi on and materials used (Welstead, J., Hirst, R., Keogh, D., Robb G. and Bainsfair, R., 2013).

At the moment, there are three possible routes for dismantled wind turbine blades: incinerati on, landfi ll or recycling.

Incinerati on is the most common disposal opti on. The advantage is that there are already numerous faciliti es in place and that the process can be carried out competi ti vely. However, 60% of the scrap is left behind as a potenti ally pollutant ash (Larsen, 2009) that needs to be placed in landfi ll. The inorganic loads also lead to the emission of hazardous fl ue gasses that can cause problems in the fl ue gas cleaning system.

Landfi ll is a common disposal opti on for wind turbine blades due to their complicated composite constructi on. However, EU legislati on discourages the disposal of waste to landfi ll and composite materials are likely to be banned from landfi ll in future European policies due to their high organic content.

Recycling is the alternati ve route for the end of life of wind turbine blades. However, there are limited potenti al end uses and end markets for the thermoset materials in current state of the art blades, making recycling of the composites challenging. The thermoset material will not melt but will eventually degrade at high temperatures or it may be att acked by certain chemicals. Reprocessing to form other plasti c artefacts is therefore exceedingly diffi cult. Recycling routes are usually based on the total destructi on of the blades with most going to the cement industry as fi ller material.

The blade developed in the WALiD project however was designed with a thermoplasti c matrix to increase the potenti al for recyclability. Since the blades would be a constant source, the recyclate would be expected to have bett er consistency than most recyclate. Potenti al end uses for thermoplasti c wind turbine blades have been investi gated and some are explained below.

4.1 Powder Impression Moulding (PIM)

This process, developed by Environmental Recycling Technologies plc (ERT), can manufacture lightweight sandwich structures from 100% mixed post-consumer polymer. Recycled plasti c by-products are milled into controlled powder blends that can then be moulded using PIM moulding

End of Life

22


technology. The process has excepti onally high tolerance to feedstock variati ons (contaminati on, dissimilar materials and parti cle size) and could therefore be a uniquely eff ecti ve recycling technology for dealing with the complex compositi on and materials of the WALiD wind turbine blade.

An example of a product manufactured using the PIM technology is shown in Figure 17. Brownwater Plasti cs LLC holds an exclusive license from ERT to manufacture and sell barge covers and other marine products that are made using the PIM process. The barge covers (that measure 200ft ² - possibly the world’s largest thermoplasti c moulding) are a superior product to existi ng fi bre glass barge covers and can be recycled at end of life.

Figure 17: Barge covers made using the PIM process (Source: Plasti cs Recycling Expo, 2014)

4.2 Retaining Walls

Traditi onally made from concrete (prone to cracking) or ti mber (prone to rotti ng); retaining walls hold back soil where natural slopes are being resisted to gain maximum fl at land. Alternati vely 100% recycled mixed polymer can be used. Ecocrib is one company in the UK who manufacture retaining walls enti rely from recycled UK plasti c waste. It creates durable (they will not rot or be aff ected by water or fungus infecti on), robust, economic and sustainable retaining walls. Ecocrib claim no waste is created during the manufacture or installati on with all surplus material re-processed to form new Ecocrib profi les, and when the retaining system reaches the end of its useful life the Ecocrib profi les can be recycled again. Certi fi ed by the Briti sh Board of Agrément (BBA), Ecocrib can achieve a design life greater than 120 years.

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Figure 18: Kett ering A14 retaining wall using 100% recycled plasti c (Source: Ecocrib, n.da)

Figure 19: Retaining wall using 100% recycled plasti c in Crick, Northamptonshire (Source: Ecocrib, n.dc)

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Figure 20: Retaining wall using recycled plasti c at Center Parcs, Woburn Forrest (Source: Ecocrib, n.db)

The Ecocrib retaining walls have been installed across the UK including 1800sqm used on the A14 J7-9 Kett ering Bypass. This project (shown in Figure 18) has diverted 160 tonnes of plasti c waste from landfi ll. Figure 19 shows part of a project in Crick, Northamptonshire where 140 tonnes of plasti c waste has been diverted from landfi ll to manufacture its 1576sqm retaining wall. Finally, Figure 20 shows part of an Ecocrib retaining wall at Center Parcs in Woburn Forrest which used 75 tonnes of recycled plasti c waste.

Ecocrib uses plasti c from bags, packaging, car bumpers and bott le tops, but these examples show the enormous scope possible with recycled polymers that could become a potenti al end of life use for the thermoplasti c materials in the WALiD blade.

4.3 3D Printing

Materials recovered from recycled WALiD wind blades could potenti ally be used as the material for 3D printi ng. 3D printi ng with thermoplasti cs is widely practi ced and may be the only choice for many applicati ons. Figure 21 is one example of a product made with a thermoplasti c material.

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Figure 21: An example of a complex item produced using thermoplasti cs (L), and its baseplate (R)(Source: Flite Club, 2016)

4.4 Decking

Recycled plasti c has been used for many years to create benches, bollards and fencing (two examples are shown in Figure 22) and is a potenti al opti on for thermoplasti c wind turbine blades.

Figure 22: Recycled plasti c bench and fencing (Source: Hahn Plasti cs Ltd, 2016)

The use of the recycled plasti c as a structural material, however, would require a greater volume of recycled material which could be an ideal use for the decommissioned WALiD blades. Across Europe, more and more recycled plasti c walkways or boardwalks are being developed and installed by a range of organisati ons (examples in Figure 23). This more cutti ng edge use has similar benefi ts to the retaining walls described in chapter 4.2, including durability, low maintenance, resistance to UV light, vandal resistance, resistance to rot, splinter-proof and the recycled plasti c products are completely recyclable at the end of their useful lifespan. No preservati ve is required therefore it complies with the requirements restricti ng the use of copper chromium arsenate. Also, recycled composite materials are completely inert and will not leach any chemicals into water or soil even in wet conditi ons. These walkways and boardwalks are also chosen because they are bett er value than their ti mber alternati ves, whilst sti ll blending harmoniously with the environments they protect.

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Figure 23: Recycled plasti c walkway and boardwalk (Source: Hahn Plasti cs Ltd, 2015)

4.5 Railway Sleepers

Railway sleepers are another example of how large quanti ti es of waste thermoplasti cs are being used for structural building materials. The most commonly used materials of wood or concrete are becoming less favourable for sleeper manufacturers. This is in response to the European ban on the use of creosote treatment from 2018, the high maintenance of wood and its reduced quality, the high weight of concrete sleepers and the fact that these can easily crack.

According to one manufacturer Lankhorst Engineered Services, Netherlands, the plasti c sleeper has high end properti es and retains these properti es during its long expected lifespan of over 50 years. This is compared to 25-30 years for creosoted oak sleepers and 10 years for untreated oak sleepers.

Figure 24: Railway sleepers made using recycled plasti c (Source: Lankhorst Mouldings, 2016)

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4.6 Use of Existing Blade Structure

Unlike the other examples in this chapter representi ng how thermoplasti c wind turbine blades can be recycled, this fi nal example is re-use with minimal disrupti on to the existi ng structure. Blades have been transformed into park benches, seats and children’s playground items by clever use of the existi ng blade structure.

Figure 25: The Wikado Playground in Rott erdam, Netherlands. (Source: Superuse Studios, 2014)

An example is shown above in Figure 25. The Wikado Playground located at a grade school in Rott erdam, Netherlands is a sustainable playground designed by Superuse Studios. Built in 2012, the enti re outdoor play area is a safe playground which uses fi ve old wind turbine blades which were cut up, reassembled and welded to create a cost effi cient and fun place for the children. Porti ons of the park include tunnels, towers, slides and even benches and seati ng for parents to eat and rest.

Making use of enti re wind turbine blades, the Dutch company has also successfully designed and built seati ng in Rott erdam and a bus shelter in Almere Poort.

These projects demonstrate the technical applicati ons and potenti al for whole blade designs and architecture. These blade designs are durable, iconic, compete economically and reduce the ecological footprint of projects in which they are used (Superuse Studios, 2014).

When whole blade structures are used they could play an additi onal valuable role as above-ground, in-use, composite material storage. In this way valuable composite material could be recovered later from such structures when economic and environmentally viable recovery or recycling methods are established. Benefi ts not achieved when composites are sent to permanent disuse in landfi ll or are incinerated.

4.7 Future Recommendations

It is clear that end of life opti ons for composite wind turbine blades is an increasing issue and landfi ll is becoming an unacceptable method of waste disposal.

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Currently, the materials in the WALiD blade provide opti ons for recyclability. This project shows that industry is waking up to the challenge, not only in terms of recycling, but also in terms of research into new materials.

A problem exists however, because the wind industry is relati vely young, there is only a limited amount of practi cal experience in the recycling of wind turbine blades, parti cularly off shore, and it will take ti me to gain this practi cal experience in the dismantling, separati on, recycling and disposal of thermoplasti c wind turbine blades. It is recommended that future work be carried out into research, industry and policy.

Further study is needed into the ease of dismantling the WALiD blade without compromising the performance of the materials. Currently, the potenti al uses identi fi ed in this chapter are largely ones that use the whole blade. However, higher value re-use may be possible and more potenti al uses could be provided if the materials can be easily separated. Also, degradati on of the blade would need to be investi gated to determine the quality of the materials at the end of life. Applicati ons for the recyclate can then be selected, for example moving the materials down the chain of importance. These points reiterate the importance of focusing on sustainable design and sustainable manufacturing eff orts early in the wind blade development process.

With the amount of waste expected from wind turbine blades, further investi gati ons are needed as to whether the infrastructure is in place to exploit the opportuniti es to recycle. Individual companies that assume responsibility for their waste management suff er, under certain circumstances, from the economies of scale and transportati on costs that exist in waste management. Also, the most important business considerati on is whether there is an end market demand for the recyclate (Reynolds, N and Pharaoh, M, 2010). The examples in this chapter have shown the possibiliti es for recycled thermoplasti c wind turbine blades, but a considerable amount of work will be required to develop and establish these routes. It makes sense to develop a recycling industry to maturity before the amount of waste reaches a high level.

There is currently litt le legislati on in place for the regulati on of end of life waste management for the wind industry in Europe. Appropriate legislati ve measures that support the enti re recycling process could sti mulate the growth needed.

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The goal of comparing the overall potenti al environmental impacts associated with the new thermoplasti c based technologies developed within the WALiD project, with equivalent wind turbine blades based on current technology has been fully achieved through this study for the materials life cycle stage.

The materials stage is important in the life cycle of the wind turbine blades. Although there are components with potenti al environmental impact within the WALiD blade, it is evident from this LCA study that the thermoplasti c materials chosen for the WALiD blade lead to lower potenti al environmental impacts compared to existi ng off shore wind blade technologies and materials.

The results in chapter 3 show that except for the WALiD blade root’s impact on resources, the new thermoplasti c based technologies developed in the WALiD project have lower impact on resources, ecosystems and human health for all parts of the blade compared with the parts of an equivalent off shore wind turbine blade based on current technology.

Recycling thermoplasti c materials in wind turbine blades remains a challenge due to both technical limitati ons and lack of legislati on. The examples in chapter 4 however have shown the vast uses for recycled thermoplasti c materials in a wide variety of sectors. These opti ons show that it is possible to create new products using waste plasti c whose properti es could be as good as, if not outperform similar products, made using virgin materials. But one thing is clear, for wind turbine blades to be used in these ways they need to be made using thermoplasti c materials.

This life cycle assessment could further benefi t from analysis of other life cycle stages. It is worth investi gati ng the manufacturing process in depth to compare impacts at this stage and also to fi nd opportuniti es to improve energy effi ciency. The potenti al for lightweight constructi on with the thermoplasti c materials could have an infl uence on the transport and installati on stage, and the operati on stage could be considered to assess the maintenance of the blades with diff erent coati ng.

Adding life cycle assessment to the decision-making process provides an understanding of the human health and environmental impact that traditi onally is not considered when selecti ng a product or process. This valuable informati on provides a way to account for the full impacts of decisions, especially those that occur outside of the site that are directly infl uenced by the selecti on of a product or process. As LCA is a tool to bett er inform decision-makers it should be included with other decision criteria to make a well-balanced decision. A life cycle cost analysis has therefore been conducted along with this LCA.

Conclusions and Recommendations

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Dong Energy. (2008). Life Cycle Approaches to assess emerging energy technologies. FP6 project NEEDS.

Ecocrib. (n.da). A14 Kett ering Bypass J7-9. [Online]. Available at htt p://www.ecocribwall.co.uk/case.html?id=14 [Accessed 12 December 2016].

Ecocrib. (n.db). Centreparcs, Woburn Forest. [Online]. Available at htt p://www.ecocribwall.co.uk/case.html?id=12 [Accessed 12 December 2016].

Ecocrib. (n.dc). Finnegans, Crick. [Online]. Available at htt p://www.ecocribwall.co.uk/case.html?id=12 [Accessed 12 December 2016].

European Commission JRC Insti tute for Environment and Sustainability. (2010). ILCD Handbook. Luxembourg: Publicati ons Offi ce of the European Union.

European Wind Energy Associati on. (2015). Wind energy scenarios for 2030. Wind Europe.

Flite Club. (2016). TILT Racing Drone full 3D printed kit. [Online]. Available at htt p://www.fl iteclub.com.au/product/ti lt-racing-drone-full-3d-printed-kit-incl-pdb/ [Accessed 13 December 2016].

Goedkoop M.J., Heijungs R., Huijbregts M., De Schryver A., Struijs J. and Van Zelm R. (2012). ReCiPe 2008, A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and the endpoint level; First editi on Report I: Characterisati on.

Hahn Plasti cs Ltd. (2015). Recycled Plasti c Decking. [Online]. Available at htt p://www.hahnplasti cs.com/uploads/redactor/Newmillerdam%20Recycled%20Plasti c%20Decking.compressed_02_12_2015.pdf [Accessed 14 December 2016].

Hahn Plasti cs Ltd. (2016). New Recycled Plasti c Product Catalogue. [Online]. Available at htt p://www.hahnkunststoff e.de/media/pdf/6a/c7/20/HAHN_Katalog_2016_DE_EN_oP_web.pdf [Accessed 14 Dec 2016].

Internati onal Energy Agency. (2014). 2013 Annual report, Technical report. Internati onal Energy Agency.

Internati onal Energy Agency. (2016). Next Generati on Wind and Solar Power from cost to value. Internati onal Energy Agency.

Lankhorst Mouldings. (2016). Plasti c Sleeper. [Online]. Available at htt p://www.lankhorstrail.com/en/rail-sleepers [Accessed 13 December 2016].

Larsen, K. (2009). Recycling wind turbine blades. Renewable Energy Focus. Elsevier Ltd. 9 (7), 70-73.

Plasti cs Recycling Expo. (2014). Brownwater Plasti cs case study. [Online]. Available at htt p://www.plasti csrecyclingexpo.com/uploads/exhibitor/PTR68175/productpdf/ert-case-studies-2014-1.pdf [Accessed 13/12/2016].

Reynolds, N., Pharaoh, M. (2010). An introducti on to Composites Recycling. Management, Recycling and Reuse of Waste Composites. Woodhead Publishing Limited, Cambridge. 3-19.

Superuse Studios. (2014). Blade Made. htt ps://issuu.com/2012architecten/docs/blademade?utm_source=tester&utm_campaign=161c50bf82-Frisse_Wind&utm_medium=email&utm_term=0_448d3290c5-161c50bf82-

Welstead, J., Hirst, R., Keogh, D., Robb G. and Bainsfair, R. (2013). Research and guidance on restorati on and decommissioning of onshore wind farms. Scotti sh Natural Heritage Commissioned Report No. 591.

Wind Europe. (2016). The European off shore wind industry, key trends and stati sti cs 1st half 2016. Wind Europe.

References

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Partners

The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013 under grant agreement number 309985

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