Avoided burden

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An illustration of the allocation of avoided burden and recycling benefits across life cycles. End of life recycling (avoided burden).png
An illustration of the allocation of avoided burden and recycling benefits across life cycles.

Avoided burden (also known as the 0:100 method or end-of-life method) is an allocation approach used in life-cycle assessment (LCA) to assess the environmental impacts of recycled and reused materials, components, products, or buildings. While the approach has been adapted to fit a variety of LCA goals, it generally considers products with recycling or reuse potential and allocates the environmental impacts of their initial production to their final life cycle. The avoided burden method is never explicitly required for LCA under the International Organization for Standardization (ISO) or European Standards (EN). In fact, these organizations only require that an allocation approach be used to properly address reuse and recycling. In this case, LCA practitioners can choose to utilize the avoided burden method based on the goal and scope of their study.

Contents

Purpose

The avoided burden approach, along with other allocation methods, exists to address the gap between product life cycles as well as to prevent the “double-counting” of certain benefits or harms that result from reusing or recycling a product. Such procedure is required under ISO 14044 as it requires the use of an allocation method to account for the reuse and recycling of previously adopted materials. [1] A LCA practitioner's selection of an allocation approach depends on the goal of the LCA study, as each approach is distinct and yields unique results.

Origin

An illustration of avoided burden in a multi-functional production process. This can be used to compare the environmental impacts of a similar product with no co-products. Avoided burden.png
An illustration of avoided burden in a multi-functional production process. This can be used to compare the environmental impacts of a similar product with no co-products.

The avoided burden method was derived from the system expansion procedure outlined in ISO 14044 for LCA. System expansion acknowledges that most production processes result in the generation of co-products. For instance, a corn mill not only produces corn, but corn oil as well. [2] Under the system expansion procedure, these co-products remain in a product's expanded system boundary, and must therefore also be analyzed. [3] Such method enables LCA practitioners to compare the impacts of multi-function production processes with the impacts of multiple single-function processes that generate the same output. As a result, the functional unit assessed in an LCA study is broadened. The avoided burden method narrows down this functional unit while also accounting for the benefits of co-production. [3] This is accomplished by subtracting the environmental impacts of producing only the co-product from the environmental impacts of producing the main product (and its co-products). [3] This type of avoided burden simplifies the comparison of different production processes. It is a common approach in the assessment of agricultural processes.

Application

End of Life Recycling

Avoided burden can also be used, and is most often used, in the context of recycling. In this setting, it is also known as the end of life recycling approach. Here, the environmental consequences between product systems are weighed and the benefits of recycling are credited to a product's first life cycle. [1] These benefits are equivalent to the environmental impacts that would have otherwise resulted from processing additional virgin materials. [4] For instance, PET bottles may be given environmental credit for the PET they contain since the material will eventually be recycled back into further PET products. [5] A product's subsequent life cycles include the environmental impacts generated from collecting, preparing, and reprocessing the product for each future use. In this case, the avoided burden method takes the environmental impacts generated from manufacturing a recyclable product with virgin materials and transfers them to the product's final life cycle. [6] As a result, the first life cycle of a product can have negative environmental impacts. The avoided burden approach is most prominent in the metal industry. In fact, the metal industry endorsed this procedure in 2006 as its primary environmental modeling method. [7] This is because the manufacturing of metals, such as aluminum and steel, have relatively high environmental impacts that can be offset by implementing the avoided burden approach in a cradle-to-grave LCA. This reduction is possible due to both the feasibility of recycling metals and the consistency of material properties between virgin and recycled metals. [4] For this reason, the aluminum can industry, for example, relies on the avoided burden method to illustrate the benefits of production. Aluminum production, which generates substantial emissions, is an energy intensive process since it consumes a vast amount of resources. [8] Recycling aluminum avoids the environmental costs of primary production. Under the avoided burden method, these avoided costs are subtracted from the cycle in which the can is first produced. These impacts can be considerable, as aluminum cans are about 70% recycled in the US, on average, and are “infinitely recyclable." [9] The same applies for scrap metal produced in metal manufacturing. If more scrap is generated during a product's use than is needed for manufacturing, the product earns a credit equivalent to the difference between the impacts of production and the impacts of reprocessing the secondary material. [10] Avoided burden therefore communicates whether a product with high recycling potential is environmentally advantageous. [8] In terms of ISO 14044, this method is often preferred to other allocation approaches due to its roots in system expansion and its closed-loop nature.

Limitations

Avoided burden is implemented in LCA where appropriate, as its results could significantly impact the outcome of a study. Users of the avoided burden approach have praised this method for showing the value of existing materials. [11] However, it is most useful when evaluating products with high recycling or reuse potential and high environmental impacts. In the case of products with low environmental impacts, ineffective recycling, and infrequent recycling, such as wood and plastics, the approach is less critical as it yields less indicative information. [4]

The avoided burden procedure operates under certain assumptions. For instance, the method assumes that the product or material assessed will be used at least twice, and that the product or material will still be in demand in the future, which could range anywhere between days to years depending on the product at hand. [8] While this may encourage designers to plan for future reuse, it also introduces a risk element to the LCA. [12] In the case the product is not recycled or reused as expected, it may fail to repay the “environmental loan” it borrowed at the time of its first LCA. [8] In this situation, the actual recycling and reuse benefits would differ from the expected benefits, and could diverge from the intended results of the initial design and production decisions. The method also assumes recycling rates. Recycling rates are variable measures that depend on consumption and capture, imports and exports, recycling yields, etc. [7] As a result, they may be difficult to accurately predict. Metal associations often publish their recycling rates in their LCAs or in similar documentation. [7] Other products, on the other hand, are less thorough, which results in challenges for LCA practitioners.

Calculation

The calculation of avoided burden varies by type, LCA scope and goal, and LCA practitioner. Although its calculation is not without some degree of subjectivity, the avoided burden in the end of life recycling approach is usually calculated as follows: [13]

Avoided Burden = (Material Recycling Rate) × (Functional Unit) × [(Impact of Virgin Production) − (Impact of Recycling)]

Building Refurbishment

Application

An illustration of life cycle stages. In many cases, building refurbishment is categorized as new life cycle rather than an extension of the use stage (green). Life cycle analysis and GHG carbon accounting.jpg
An illustration of life cycle stages. In many cases, building refurbishment is categorized as new life cycle rather than an extension of the use stage (green).

Avoided burden is implemented differently in building refurbishment than in products. In LCA, building refurbishment is often treated as the beginning of a new life cycle as opposed to a continuation of the “use stage” due to the significant environmental impacts incurred by the production of most building products and its exclusion from previous assessments, per EN 15978. [1] [14] Building refurbishment may include repair, such as that of a steel frame, or upgrades, such as that of the facade. In this case, ISO 14044 still applies, resulting in a need for an allocation approach to consider the flow between “previous and new life cycles”. [1] Similar to the end of life recycling approach, virtually all of the environmental impacts from the production phase are assigned to the building's second use. However, unlike the end of life recycling approach, the benefits of using the recycled materials are not considered, only their creation. [1] This curates a more accurate depiction of the value of existing materials in refurbishment projects.

Research and Limitations

The avoided burden method in building reuse assumes that certain building materials and components will be used beyond their first life cycle. [12] Much like with products, this encourages engineers and architects to plan for future use. However, this future use can be challenging to predict due to the longer lifetime of buildings. [12] Avoided burden also requires more work from the LCA practitioner to develop an accurate representation of the existing building in order to yield reliable results. [11] Rarely do refurbishment projects require a detailed mapping of the existing structure. However, an expansive bill of materials is required for an accurate LCA, which could result in increased consultancy costs. [11]

Similar to product LCA, there several methods an LCA practitioner can use to assess the environmental benefits and burdens of refurbishment and reuse. Most include drawbacks such as a neglect of remaining materials in a building or an inability to accommodate for past benefits. [1] For this reason, researchers are developing methods that remedy these issues.

Implementation in Other Allocation Approaches

Other allocation approaches have built off the avoided burden framework to evaluate the benefits and burdens of recycling and reuse across multiple product life cycles. These approaches include, but are not limited to, the 50:50 approach and the Product Environmental Footprint (PEF) approach.

50:50 Approach

The 50:50 approach, or 50:50 rule, was first proposed in 1994. [15] It is considered a compromise between the avoided burden approach and the cut-off approach, an approach that attributes the environmental impacts of each life cycle stage to the life cycle in which it occurs. [12] The 50:50 approach evenly distributes the benefits and burdens of using recycled materials to a product's first and second life cycles. More specifically, 50% of the environmental impacts of production are allocated to the first life cycle while the second life cycle is allocated the remaining 50% as well as the impacts from reprocessing. [1] Despite the benefits that stem from combining the cut-off and avoided burden approaches, the 50:50 approach is not often used in practice. [16]

PEF Approach

The PEF approach builds off the 50:50 approach as it also distributes benefits and burdens across multiple life cycles. However, it also considers the down-cycling of materials and the market demand for recycled products. [1] In this case, the first life cycle is assigned half of the environmental impacts of production, while the second life cycle is allocated the remaining half in addition to the reprocessing impacts multiplied by a quality factor. [1] In doing so, the PEF approach accounts for a presumably circular economy. This is the greatest strength of the PEF approach, and for this reason, it is expected to prevail in the future. [16] Currently, however, LCA practitioners face difficulties using this method due to a lack of data to approximate quality factors. [16] This information is important to LCA practitioners, as it can often tip the balance between two compared alternative products or materials.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Recycling</span> Converting waste materials into new products

Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on its ability to reacquire the properties it had in its original state. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. It can also prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, reducing energy use, air pollution and water pollution.

<span class="mw-page-title-main">Life-cycle assessment</span> Methodology for assessing environmental impacts

Life cycle assessment (LCA), also known as life cycle analysis, is a methodology for assessing environmental impacts associated with all the stages of the life cycle of a commercial product, process, or service. For instance, in the case of a manufactured product, environmental impacts are assessed from raw material extraction and processing (cradle), through the product's manufacture, distribution and use, to the recycling or final disposal of the materials composing it (grave).

<span class="mw-page-title-main">Green building</span> Structures and processes of building structures that are more environmentally responsible

Green building refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from planning to design, construction, operation, maintenance, renovation, and demolition. This requires close cooperation of the contractor, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building also refers to saving resources to the maximum extent, including energy saving, land saving, water saving, material saving, etc., during the whole life cycle of the building, protecting the environment and reducing pollution, providing people with healthy, comfortable and efficient use of space, and being in harmony with nature Buildings that live in harmony. Green building technology focuses on low consumption, high efficiency, economy, environmental protection, integration and optimization.’

<span class="mw-page-title-main">Waste hierarchy</span> Tool to evaluate processes protecting the environment

Waste hierarchy is a tool used in the evaluation of processes that protect the environment alongside resource and energy consumption from most favourable to least favourable actions. The hierarchy establishes preferred program priorities based on sustainability. To be sustainable, waste management cannot be solved only with technical end-of-pipe solutions and an integrated approach is necessary.

<span class="mw-page-title-main">Downcycling</span> Recycling waste into products of lower quality

Downcycling, or cascading, is the recycling of waste where the recycled material is of lower quality and functionality than the original material. Often, this is due to the accumulation of tramp elements in secondary metals, which may exclude the latter from high-quality applications. For example, steel scrap from end-of-life vehicles is often contaminated with copper from wires and tin from coating. This contaminated scrap yields a secondary steel that does not meet the specifications for automotive steel and therefore, it is mostly applied in the construction sector.

<span class="mw-page-title-main">Material efficiency</span>

Material efficiency is a description or metric ((Mp) (the ratio of material used to the supplied material)) which refers to decreasing the amount of a particular material needed to produce a specific product. Making a usable item out of thinner stock than a prior version increases the material efficiency of the manufacturing process. Material efficiency is associated with Green building and Energy conservation, as well as other ways of incorporating Renewable resources in the building process from start to finish.

<span class="mw-page-title-main">Reuse</span> Using an item again after it has been used, instead of recycling or disposing

Reuse is the action or practice of using an item, whether for its original purpose or to fulfill a different function. It should be distinguished from recycling, which is the breaking down of used items to make raw materials for the manufacture of new products. Reuse – by taking, but not reprocessing, previously used items – helps save time, money, energy and resources. In broader economic terms, it can make quality products available to people and organizations with limited means, while generating jobs and business activity that contribute to the economy.

<span class="mw-page-title-main">Waste minimisation</span> Process that involves reducing the amount of waste produced in society

Waste minimisation is a set of processes and practices intended to reduce the amount of waste produced. By reducing or eliminating the generation of harmful and persistent wastes, waste minimisation supports efforts to promote a more sustainable society. Waste minimisation involves redesigning products and processes and/or changing societal patterns of consumption and production.

<span class="mw-page-title-main">Cradle-to-cradle design</span> Biomimetic approach to the design of products

Cradle-to-cradle design is a biomimetic approach to the design of products and systems that models human industry on nature's processes, where materials are viewed as nutrients circulating in healthy, safe metabolisms. The term itself is a play on the popular corporate phrase "cradle to grave", implying that the C2C model is sustainable and considerate of life and future generations—from the birth, or "cradle", of one generation to the next generation, versus from birth to death, or "grave", within the same generation.

<span class="mw-page-title-main">Life-cycle engineering</span>

Life-cycle engineering (LCE) is a sustainability-oriented engineering methodology that takes into account the comprehensive technical, environmental, and economic impacts of decisions within the product life cycle. Alternatively it can be defined as “sustainability-oriented product development activities within the scope of one to several product life cycles.” LCE requires analysis to quantify sustainability, setting appropriate targets for environmental impact. The application of complementary methodologies and technologies enables engineers to apply LCE to fulfill environmental objectives.

Design for the environment (DfE) is a design approach to reduce the overall human health and environmental impact of a product, process or service, where impacts are considered across its life cycle. Different software tools have been developed to assist designers in finding optimized products or processes/services. DfE is also the original name of a United States Environmental Protection Agency (EPA) program, created in 1992, that works to prevent pollution, and the risk pollution presents to humans and the environment. The program provides information regarding safer chemical formulations for cleaning and other products. EPA renamed its program "Safer Choice" in 2015.

Ecological design or ecodesign is an approach to designing products and services that gives special consideration to the environmental impacts of a product over its entire lifecycle. Sim Van der Ryn and Stuart Cowan define it as "any form of design that minimizes environmentally destructive impacts by integrating itself with living processes." Ecological design can also be defined as the process of integrating environmental considerations into design and development with the aim of reducing environmental impacts of products through their life cycle.

<span class="mw-page-title-main">Sustainable packaging</span> Packaging which results in improved sustainability

Sustainable packaging is the development and use of packaging which results in improved sustainability. This involves increased use of life cycle inventory (LCI) and life cycle assessment (LCA) to help guide the use of packaging which reduces the environmental impact and ecological footprint. It includes a look at the whole of the supply chain: from basic function, to marketing, and then through to end of life (LCA) and rebirth. Additionally, an eco-cost to value ratio can be useful The goals are to improve the long term viability and quality of life for humans and the longevity of natural ecosystems. Sustainable packaging must meet the functional and economic needs of the present without compromising the ability of future generations to meet their own needs. Sustainability is not necessarily an end state but is a continuing process of improvement.

<span class="mw-page-title-main">Sustainable engineering</span> Engineering discipline

Sustainable engineering is the process of designing or operating systems such that they use energy and resources sustainably, in other words, at a rate that does not compromise the natural environment, or the ability of future generations to meet their own needs.

<span class="mw-page-title-main">Eco-costs</span>

Eco-costs are the costs of the environmental burden of a product on the basis of prevention of that burden. They are the costs which should be made to reduce the environmental pollution and materials depletion in our world to a level which is in line with the carrying capacity of our earth.

The EVR model is a life cycle assessment based method to analyse consumption patterns, business strategies and design options in terms of eco-efficient value creation. Next to this it is used to compare products and service systems.

Environmentally sustainable design is the philosophy of designing physical objects, the built environment, and services to comply with the principles of ecological sustainability and also aimed at improving the health and comfort of occupants in a building. Sustainable design seeks to reduce negative impacts on the environment, the health and well-being of building occupants, thereby improving building performance. The basic objectives of sustainability are to reduce the consumption of non-renewable resources, minimize waste, and create healthy, productive environments.

Life cycle thinking is an approach that emphasizes the assessment and minimization of environmental impacts at all stages of a product's life. This concept seeks to avoid shifting environmental burdens from one stage of the product's life to another. It also recognizes the importance of technological innovation in tackling environmental issues.

<span class="mw-page-title-main">Cotton recycling</span>

Cotton recycling is the process of converting cotton fabric into fibers that can be reused into other textile products.

Environmental systems analysis (ESA) is a systematic and systems based approach for describing human actions impacting on the natural environment to support decisions and actions aimed at perceived current or future environmental problems. Impacts of different types of objects are studied that ranges from projects, programs and policies, to organizations, and products. Environmental systems analysis encompasses a family of environmental assessment tools and methods, including life cycle assessment (LCA), material flow analysis (MFA) and substance flow analysis (SFA), and environmental impact assessment (EIA), among others.

References

  1. 1 2 3 4 5 6 7 8 9 Obrecht, Tajda Potrč; Jordan, Sabina; Legat, Andraž; Ruschi Mendes Saade, Marcella; Passer, Alexander (2021). "An LCA methodolody for assessing the environmental impacts of building components before and after refurbishment". Journal of Cleaner Production. 327: 129527. doi: 10.1016/j.jclepro.2021.129527 . S2CID   240218883 – via Elsevier Science Direct.
  2. ↑ Curran, Mary Ann (2014). Life Cycle Assessment Student Handbook. John Wiley & Sons, Incorporated. pp. 3h. ISBN   9781119083559.
  3. 1 2 3 Klöpffer, Walter; Grahl, Birgit (2014). Life Cycle Assessment (LCA): A Guide to Best Practice (1st ed.). John Wiley & Sons, Incorporated. p. 97. ISBN   9783527655656.
  4. 1 2 3 Pacheco-Torgal, Fernando; Cabeza, Luisa F.; Labrincha, Joao; Giuntini de Magalhaes, Aldo (2013). Eco-Efficient Construction and Building Materials : Life Cycle Assessment (LCA), Eco-Labelling and Case Studies. Elsevier Science & Technology. pp. 520–521. ISBN   9780857097729.
  5. ↑ Nicholson, Anna. "LCA allocation methods in open-loop recycling: incentivizing recycled material sourcing and creation of recyclable products" (PDF). Archived from the original (PDF) on 25 April 2012. Retrieved 1 April 2011.
  6. ↑ Zink, Trevor; Geyer, Roland; Startz, Richard (2015). "A Market-Based Framework for Quantifying Displaced Production from Recycling or Reuse". Journal of Industrial Ecology. 20 (4): 719–729. doi:10.1111/jiec.12317. S2CID   153968728 – via Wiley Online Library.
  7. 1 2 3 Santero, Nicholas; Hendry, Josh (2016). "Harmonization of LCA methodologies for the metal and mining industry". The International Journal of Life Cycle Assessment. 21 (11): 1543–1553. doi: 10.1007/s11367-015-1022-4 . S2CID   113236544 – via Springer Link.
  8. 1 2 3 4 Frischknecht, Rolf (2010). "LCI modelling approaches applied on recycling of materials in view of environmental sustainability, risk perception and eco-efficiency". The International Journal of Life Cycle Assessment. 15 (7): 666–671. doi:10.1007/s11367-010-0201-6. S2CID   154594690 – via Springer Link.
  9. ↑ The Aluminum Association (2014-12-17). "Study Shows Aluminum Can Continues to be Sustainable Beverage Package of Choice: 20 Percent Improvement in Carbon Footprint; 70 Percent Recycled Content 3X Other Packages". U.S.Newswire. Washington.
  10. ↑ Skszek, Timothy; Wagner, David; Conklin, Jeff; Zaluzec, Matthew (2015). The Multi Material Lightweight Vehicle (MMLV) Project. SAE International. p. 117. ISBN   9780768087192.
  11. 1 2 3 Kjær Zimmermann, R; Nygaard Rasmussen, F; Kanafani, K; Malabi Eberhardt, L C; Birgisdóttir, H (2022). "Reviewing Allocation Approaches and Modelling in LCA for Building Refurbishment". IOP Conference Series: Earth and Environmental Science. Bristol. 1078 (1): 012095. Bibcode:2022E&ES.1078a2095K. doi: 10.1088/1755-1315/1078/1/012095 . S2CID   252276486 – via ProQuest.
  12. 1 2 3 4 De Wolf, Catherine; Hoxha, Endrit; Fivet, Corentin (2020). "Comparison of environmental assessment methods when reusing building components: A case study". Sustainable Cities and Society. 61: 102322. doi:10.1016/j.scs.2020.102322. S2CID   225799176 – via Elsevier Science Direct.
  13. ↑ Geyer, Roland. "Life Cycle Inventory Analysis". Archived from the original on 9 July 2010. Retrieved 1 April 2011.
  14. ↑ Röck, Martin; Ruschi Mendes Saade, Marcella; Baloutski, Maria; Nygaard Rasmussen, Freja; Birgisdottir, Harpa; Frischknecht, Rolf; Habert, Guillaume; Lützkendorf, Thomas; Passer, Alexander (2020). "Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation". Applied Energy. 258: 114107. doi: 10.1016/j.apenergy.2019.114107 . hdl: 20.500.11850/381047 . S2CID   210979015 – via Elsevier Science Direct.
  15. ↑ Weidema, Bo (2000). "Avoiding Co-Product Allocation in Life-Cycle Assessment". Journal of Industrial Ecology. 4 (3): 11–33. doi:10.1162/108819800300106366. S2CID   154350218 – via Wiley Online Library.
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