Ex-ante Life Cycle Assessment Research Articles

Ex-ante life cycle assessment of directed energy deposition based additive manufacturing: A comparative gearbox production case study

As new technologies emerge is necessary to assess if they can actually contribute to sustainable improvement of industrial processes. Life Cycle Assessment (LCA) is a valuable tool to determine environmental impacts and compare systems. However, this comparison raises challenges when they have different maturity. This paper performs ex-ante LCA of an additive manufacturing (AM) technology, based on a step-wise approach built with parametrized modelling, allowing fair comparison with its conventional counterpart, for the study case of a gearbox component. Results show that AM technology generates higher impacts than conventional manufacturing (CM) casting process, using baseline values. These impacts can be reduced by 94% with best operating performances from literature, with emissions from 4520 to 264 kg CO2 eq./kg piece, and non-significant difference with CM (demonstrated by Monte Carlo sampling). A 58% weight reduction is necessary for the AM process to improves its environmental sustainability. This research provides eco-design recommendations supporting decision making for further development of new technology.

Terminology for future-oriented life cycle assessment: review and recommendations

PurposeSome future-oriented life cycle assessment (LCA) terms, particularly prospective and ex-ante, show notable increase in use in publications over the last decade. However, scholars have pointed out that it is currently unclear exactly what these terms mean and how they are related. This paper aims to explain defining differences between future-oriented LCA terms and provide terminology recommendations.MethodsExisting definitions of future-oriented LCA terms were reviewed and analyzed. Workshops were held where defining differences of future-oriented LCA terms were discussed.ResultsTemporal positionality and technology maturity appear to be two critical aspects of future-oriented LCA. Prospective and ex-ante LCA are similar, with the possible difference that ex-ante LCA always involves an increase in technology maturity in the future. Considering the notable similarities, it seems reasonable to converge terms to mitigate field fragmentation and avoid terminology confusion.ConclusionsTo denote LCA studies with a future temporal positionality, we recommend using the term prospective LCA, defined as “LCA that models the product system at a future point in time relative to the time at which the study is conducted”. Furthermore, since technology maturity is clearly a critical aspect for prospective LCA, we recommend prospective LCA studies to clearly define the maturity of the technologies modeled in the production system.

Integrating ex-ante and prospective life-cycle assessment for advancing the environmental impact analysis of emerging bio-based technologies

Unlike the fossil-based alternatives, many emerging bio-based technologies are still at the early lab or pilot scale and are not representative of optimized industrial conditions. This makes a robust comparison of their environmental performances via life-cycle assessment (LCA) challenging. We propose a framework to combine scaling-up projections of early-stage technologies (ex-ante LCA) with the influence of future socio-economic scenarios (prospective LCA), using a range of new bio-based polymers produced from forest residues as case study. The combined framework takes a step-by-step approach in modifying process inventories and projecting them to a future industrial scale for the environmental impact assessment. In our case study, the climate change impact from lab-scale processes decreases from 105–471 kg CO2-eq./kg of polymer to 9–14 kg CO2-eq./kg after the application of ex-ante LCA, with the highest reduction (83 %) coming from identified process synergies (e.g., solvent recovering). Combining the ex-ante and prospective LCA additionally reduces the impact up to 56 % by 2050, relative to ex-ante LCA results only. Other environmental impacts decrease as well, particularly freshwater eutrophication (up to 99 % reduction), photochemical oxidant formation (99 %), and marine eutrophication (98 %). The framework secures a more robust comparison of emerging bio-based products with conventional fossil-based alternatives, and as such it helps the identification of the improvements in both the bio-based technological processes and background supply chains that are needed to make bio-based systems outperform their fossil counterparts. A consistent integration of ex-ante and prospective LCA is instrumental to prioritize research and investments for upscaling the early-stage technologies that are most promising from a sustainability perspective, and ultimately guide a sustainable transition towards a circular bioeconomy.

A multi-criteria framework for the ecodesign of bio-based materials at early development stages

Ex-ante life cycle assessment (LCA) allows for a holistic environmental evaluation of novel products at research and development (R&D) stages when the potential for environmental improvement is higher. Multi-criteria decision analysis (MCDA) incorporates techno-economic attributes and considers decision-makers’ (DMs) perspectives. Thus, integrating ex-ante LCA and MCDA is key for R&D ecodesign. This article proposes a framework combining ex-ante LCA with multi-attribute value theory and stochastic multi-acceptability analysis (SMAA) for novel bio-based materials in four steps: i) Problem structuring, ii) LCA scope, inventory, and scale-up, iii) Performance table, elicitation, and MCDA calculations, and iv) Interpretation and recommendations. The LCA-MCDA framework provides a structured way to model upscaled environmental impacts and encompass technical and economic performances in a global value while considering novel materials' potential application and functionality. The framework is applied to lab-scale starch films for food packaging, comparing them with commercial polymers for cost, environmental, and technical criteria according to three DMs' perspectives (biopolymer/sustainability researchers). Materials, formulations, and scenarios are assessed on a 1-kg basis with properties as technical criteria. The commercial films outperform the novel films, primarily due to technical performance. Scale-up and plasticizer scenarios show potential for reducing environmental impacts but do not alter the ranking of alternatives. SMAA shows that the ranking highly depends on the criterion weights; conversely, individual DM's perspectives lead to similar results. Materials are also compared for equivalent properties (stiffness, strength, and moisture barrier) by applying material substitution factors. The most favorable results for the starch films are achieved for equivalent stiffness, thus suggesting further investigation for rigid applications. Furthermore, suggestions for applying the framework to other cases are provided. The LCA-MCDA framework facilitates the communication of LCA results with cost and technical performance, supporting R&D in dealing with trade-offs and identifying pathways toward more sustainable and competitive production of bio-based materials.

Data-driven approaches for sustainable agri-food: coping with sustainability and interpretability

Motivated by the increasing interest in machine learning algorithms for data-driven applications in agri-food addressing sustainability issues and by the ongoing discussion on the interpretability and sustainability of such algorithms, we compare congruently the performance of some state-of-the-art techniques and a new version (here proposed for the first time) of Co-Active Neuro-Fuzzy Inference System, equipped with fractional regularization (CANFIS-T for short). To this end, we consider two case studies retrieved from the literature and dealing with two approaches for sustainability development, i.e. ex-ante Life Cycle Assessment and Supply Chain Operations Reference in the agri-food context. Such approaches are set in a data-driven framework and completed by the above-mentioned machine learning techniques. The state-of-the-art techniques from the relevant literature are the ensemble ANFIS, Radial Basis Function Network and Decision Tree. The techniques are compared from the computational, interpretability and energy standpoints. From a formal perspective, we prove what negatively affects the accuracy of ensemble ANFIS. On the basis of the performed experiments, we notice that except for the ensemble ANFIS, all the approaches can be regarded as sustainable, with energy savings over 99%, while only CANFIS-T keeps both good accuracy and interpretability (with up to 4 rules) when the number of input and output variables gets large.

Ex-ante life cycle assessment of commercial-scale cultivated meat production in 2030

PurposeCultivated meat (CM) is attracting increased attention as an environmentally sustainable and animal-friendly alternative to conventional meat. As the technology matures, more data are becoming available and uncertainties decline. The goal of this ex-ante life cycle assessment (LCA) was to provide an outlook of the environmental performance of commercial-scale CM production in 2030 and to compare this to conventional animal production in 2030, using recent and often primary data, combined with scenario analysis.MethodsThis comparative attributional ex-ante LCA used the ReCiPe Midpoint impact assessment method. System boundaries were cradle-to-gate, and the functional unit was 1 kg of meat. Data were collected from over 15 companies active in CM production and its supply chain. Source data include lab-scale primary data from five CM producers, full-scale primary data from processes in comparable manufacturing fields, data from computational models, and data from published literature. Important data have been cross-checked with additional experts. Scenarios were used to represent the variation in data and to assess the influence of important choices such as energy mix. Ambitious benchmarks were made for conventional beef, pork, and chicken production systems, which include efficient intensive European animal agriculture and incorporate potential improvements for 2030.Results and discussionCM is almost three times more efficient in turning crops into meat than chicken, the most efficient animal, and therefore agricultural land use is low. Nitrogen-related and air pollution emissions of CM are also lower because of this efficiency and because CM is produced in a contained system without manure. CM production is energy-intensive, and therefore the energy mix used for production and in its supply chain is important. Using renewable energy, the carbon footprint is lower than beef and pork and comparable to the ambitious benchmark of chicken. Greenhouse gas profiles are different, being mostly CO2 for CM and more CH4 and N2O for conventional meats. Climate hotspots are energy used for maintaining temperature in reactors and for biotechnological production of culture medium ingredients.ConclusionsCM has the potential to have a lower environmental impact than ambitious conventional meat benchmarks, for most environmental indicators, most clearly agricultural land use, air pollution, and nitrogen-related emissions. The carbon footprint is substantially lower than that of beef. How it compares to chicken and pork depends on energy mixes. While CM production and its upstream supply chain are energy-intensive, using renewable energy can ensure that it is a sustainable alternative to all conventional meats.RecommendationsCM producers should optimize energy efficiency and source additional renewable energy, leverage supply chain collaborations to ensure sustainable feedstocks, and search for the environmental optimum of culture medium through combining low-impact ingredients and high-performance medium formulation. Governments should consider this emerging industry’s increased renewable energy demand and the sustainability potential of freed-up agricultural land. Consumers should consider CM not as an extra option on the menu, but as a substitute to higher-impact products.

Ex-ante life cycle assessment of polyols using carbon captured from industrial process gas

This study presents an ex-ante life cycle assessment of a carbon capture and utilization technology that converts carbon emissions from the blast furnace gas of a steel mill to valuable intermediates for the production of polyols.

Stochastic Ex-Ante LCA under Multidimensional Uncertainty: Anticipating the Production of Undiscovered Microalgal Compounds in Europe.

Due to their biodiversity, microalgae represent a promising source of high-value compounds that bioprospecting is aiming to reveal. Performing an ex-ante Life Cycle Assessment (LCA) to anticipate and potentially minimize the environmental burden associated with the European production of a bioprospected microalgal compound is subject to substantial and multi-factorial uncertainty as the compound remains undiscovered. Given that any microalgal strain could potentially host the compound of interest, the ex-ante LCA should consider this bioprospecting uncertainty together with the uncertainty on the technology and the production mix. Using a parameterized cultivation simulation and consequential LCA model and an extensive stochastic pseudo Monte Carlo approach, we define and propagate techno-operational, bioprospecting, and production mix uncertainties for a microalgal compound being currently bioprospected in Europe. We perform global sensitivity analysis using different sampling strategies to identify the main contributors to the total output variance. Overall, the uncertainty propagation allowed us to define and analyze the probabilistic scope for the potential environmental impacts in the emerging production of high-value microalgal compounds in Europe based on current knowledge. These findings can support policy-making as well as actors in the microalgal sector toward technological paths with lower environmental impact.

Cradle-to-Gate life cycle assessment of recycling processes for carbon fibers: A case study of ex-ante life cycle assessment for commercially feasible pyrolysis and solvolysis approaches

Waste that derives from manufacturing processes and end-of-life products of the transportation industry is a cause of increasing concern globally. Therefore, systems must be developed to manage such waste and to mitigate greenhouse gas (GHG) emissions. In this study, the carbon fiber reinforced polymer (CFRP) recycle process was analyzed to assess its environmental friendliness. The recycling processes at the Carbon Fiber Recycling Co., i.e., pyrolysis, and Hitachi Chemical, i.e., solvolysis, both of which are currently in production scale, were analyzed. The scaling effect was employed to assess the environmental impacts of the production scale. The results showed that either recycling method offers promising results for reducing environmental impacts, as compared with producing virgin carbon fibers (vCFs). GHG emissions from the Carbon Fiber Recycling Co. pyrolysis were 1.52 kg-CO2 eq/kg while that of Hitachi Chemical solvolysis was 1.92 kg-CO2 eq/kg. GHG emissions resulting from both methods were below the GHG emissions produced by vCFs (24.00 kg-CO2eq/kg). By factoring the GHG credits created from the by-products of these processes, the GHG emissions from the Carbon Fiber Recycling Co. pyrolysis were 0.57 kg-CO2 eq/kg and that from Hitachi Chemical solvolysis was −0.54 kg-CO2 eq/kg. Additionally, the results of this study were consistent with other GHG studies, suggesting credibility.

Ex-ante life cycle assessment framework and application to a nano-reinforced biopolymer film based on mango kernel

This article proposes a framework for ex-ante life cycle assessment (LCA) of biopolymers at low TRL, including: (i) scale-up; (ii) scenarios for processes and modelling choices; (iii) comparison with a fossil-based polymer, considering material substitution factors. The framework was applied to analyse a mango kernel starch (MKS) film and compare it with low-density polyethylene (LDPE). Mango seeds (feedstock) were modelled as burden-free since they do not have economic value (baseline). An industrial-scale model was built for the production of starch nanocrystals (SNC) and MKS film using process calculations based on experimental data. Most impacts occur at starch and SNC extraction due to steam and acid consumption. Compared to LDPE, MKS performs better in non-renewable energy use but worse in climate change, freshwater eutrophication, and terrestrial acidification. Scenario analysis showed that yield enhancement and acid shifting could considerably reduce impacts. The proposed framework shows potential to support sustainable innovation of biopolymers.

Ex-ante life cycle assessment and scale up: A protein production case study

Life cycle assessment (LCA) is a well-known tool that has been able to provide insights into the environmental impact and hotspots of systems and technologies that are established in the market. Nevertheless, both for emerging processes that are only available at laboratory or pilot scale and when more future oriented in its perspective, the application of LCA becomes more complex and difficult. There is as of yet no consensus in the literature on how to conduct ex-ante LCA and many challenges discussed in the literature have yet to be cleared. This paper aims to highlight the implementation of ex-ante LCA with a specific focus on upscaling processes from laboratory to industrial scale. A new production process of proteins obtained from rapeseed cake serves as a case study to illustrate both the challenges encountered as well as the value and necessity of future oriented LCA, LCC and scaleup. The challenges found in this work include data availability, unknown final uses and functions, complexity of upscaling, and uncertainty. The results show a strong difference between laboratory scale and industrial scale costs and impacts, which are when upscaled lower compared to the impact of other protein sources, thus uncovering the environmental benefits of protein obtained from rapeseed cake.

Can bioleaching of NIB magnets be an answer to the criticality of rare earths? An ex-ante Life Cycle Assessment and Material Flow Cost Accounting

The instability of rare earth elements (REEs) supply chains due to, among others, geopolitical factors brought alternative sources of REEs under the spotlight. Waste from electrical and electronic equipment (WEEE) is considered one of such sources. WEEE recycling is seen as a way not only to mitigate the aforementioned REEs supply risk but also to benefit the environment and society caught currently in a precarious position. Within this context, bioleaching for REEs recovery is gaining attraction, considering that, so far, this process has mainly been used to recover other elements (e.g., Cu, Ni, Zn, Al, Au, Ag). Hitherto, a few lab-scale studies on Nd, Dy, and Pr bioleaching from NIB magnets were identified in the open literature, whereas only one study attempted to perform a simplified LCA analysis of the process. Ergo, this study aims at filling this knowledge gap. For this purpose, the Life Cycle Assessment (LCA) and Material Flow Cost Accounting (MFCA) were performed to assess the process' environmental and economic feasibility after scaling it up from a lab to a pilot scale. Moreover, a break-even analysis was performed to assess the competitiveness of the technology. As the bioleaching of NIB magnets is an emerging concept, this study aimed to identify future process optimisation and development directions. The process was divided into six stages (i.e., demagnetising, shredding, bacteria cultivation, bioleaching, REEs extraction, and oxidation), analysed individually and collectively. Electricity and oxalic acid consumption, together with investment costs, were identified as the main hotspots for future improvement. • Permanent NIB magnets can be recycled to recover rare earth elements. • Nd, Dy and Pr bioleaching from these magnets is a promising emerging technology. • Environmental and economic hotpots of this technology were identified. • Electric energy and oxalic acid consumption resulted environmentally impactful. • High investment costs might compromise the profitability of the process.

Management of Agricultural Produces and Lifecycle

Abstract: The agricultural revolution was the key development in the rise of human civilization. It’s a varied field that produces a wide array of products which are important to us. As our global populations are growing faster the competition for natural resources will increase resulting in pressure on agricultural production of food, fiber, energy, various high-value by-products, etc. With upgraded concerns related to environmental impacts associated with the needs of a growing population, a life cycle assessment (LCA) framework will help to determine areas of greatest impact. The LCA methodology was mainly developed for industrial operations but we are using them in a wider range of fields which includes agriculture. Many factors increase the complexity of determining impacts associated with agricultural production The lack of consistent methodology of some impacts that are of major concern to agriculture (e.g., land and water usage) increases the difficulty or complications of this analysis. This paper attempts to review some of these issues and give perspective to the LCA expert in the field of agriculture. Keywords: Life cycle assessment, Ex-ante LCA, Technology assessment, New technology, Emerging technology

Life cycle assessment of tiger puffer (Takifugu rubripes) farming: A case study in Dalian, China

In China, energy consumption and carbon emission by the aquaculture industry have become major problems. The tiger puffer (Takifugu rubripes) is an emerging aquaculture species in China, but its environmental impact during the farming process has not yet been evaluated systematically. To the best of our knowledge, this is the first life cycle assessment (LCA) of tiger puffer land-sea relay strategy in Dalian, China. To analyze the environmental impact of the tiger puffer farming process, the following four stages were considered: seed rearing, deep-sea cage farming-1, industrial recirculating aquaculture, and deep-sea cage farming-2. The LCA software GaBi 10.5 academy version and CML-IA-Jan. 2016-world method were used to calculate the environmental impacts. According to the LCA results, marine aquatic ecotoxicity potential was the largest contributor to the environmental impact, and industrial recirculating aquaculture was the largest farming stage in the whole tiger puffer farming process. Energy in the form of electricity, coal, and gasoline was consumed to maintain the power supply in the tiger puffer farming process, and it was a key factor that influenced the environmental performance. Based on the sensitivity and energy analyses, energy consumption for equipment operation at the industrial recirculating aquaculture stage, feed consumption, and gasoline consumption for transportation at the deep-sea cage farming-2 stage need to be carefully considered. The following improvement measures were suggested to improve the environmental performance of tiger puffer farming and the aquaculture industry: establish electricity, wind power, and solar energy integrated management systems; ex-ante LCA for parameter optimization in future technology research and development; and new production strategies such as aquaponics and integrated multi-trophic aquaculture. Moreover, life cycle inventory (LCI) of tiger puffer land-sea relay farming was established to obtain essential information, enrich aquaculture LCI databases, and support aquaculture LCA research.

Environmental assessment of an innovative lithium production process

The recent development towards a battery-powered electric vehicle industry has led to a significant rise in the demand for high-grade Lithium (Li). Global Li is predominately produced from brines (salar or geothermal) and from hard-rocks, while the amount of Li produced from recycling (e.g. from waste batteries) is still negligible, although it is expected to increase in the near future. Li extraction from hard rocks and brines is also associated with environmental issues, such as (i) consumption of a large quantity of reagents, (ii) high water footprint (especially in the case of brines). Therefore, ensuring a clean, stable and sustainable supply of Li is a key point in the European agenda to reach its ambitious climate targets by 2050.Building on this need, a LiOH production process is under development at KU Leuven (C3 SOLVOLi+ project). This process concentrates technical grade LiCl from the roasting of low-content Li sources. Subsequently, it converts the concentrated technical grade LiCl into aqueous LiOH by mean of a series of processes. The presented environmental analysis, based on a ex-ante Life Cycle Assessment, highlights the potential environmental hotspots that can potentially hinder the breakthrough of the technology, providing useful insights on unit processes requiring optimizations during future upscaling. In particular, at this early stage of development, the optimization and the recycling of the chemicals used in the process seems to be the most efficient strategy to reduce the overall environmental impact of the process. Future studies foresee to enlarge the current analysis to the comparison with other processes for LiOH production. A lower environmental footprint can indeed help to strength the position of the proposed process into the future market for LiOH production.

Ex-ante life cycle assessment of a partially reusable packaging system for dry-cured ham slices

<abstract> <p>To limit the huge damage caused by plastic pollution, major changes need to be made in the food and beverage packaging sector. In this context, a new packaging system for dry-cured ham slices, containing natural antioxidants, was developed; it consists of a reusable polymer tray sealed with disposable polymer film. The life cycle of the packaging was assessed to compare its environmental impacts with a reference disposable packaging system already in use. The life cycle assessment was performed in accordance with the ISO 14040-14044 series; the system was model using the Gabi software and the ILCD PEF method was used to evaluate the impacts. The functional unit chosen was to pack 1000 batches of 4 slices of dry-cured ham in France. Three packaging scenarios were compared: a reference disposable packaging system, incinerated at end of life; the partially reusable packaging, recycled at end of life and the same partially reusable packaging, incinerated at end of life. The study of the relative impacts of each scenario revealed that for the reference packaging, the production of the tray was the highest-impact stage. With the reusable packaging, the highest-impact stages were the thermosealing process and the production of the trays and films. A significant reduction in all impacts was observed with the use of the reusable packaging. Sensitivity analysis was carried out to study the influence of the breakage rate of the tray during reuse and the number of reuse cycles of the tray. Except for freshwater resource depletion, the reusable packaging had lower environmental impacts even with a high tray breakage rate or a low number of reuses. This paper demonstrates the interest of this reusable and recyclable food contact packaging to lower the environmental footprint of packaging; the reuse and recycling stages now need to be tested in real situations for the packaging prototype to confirm the feasibility of the reuse process.</p> </abstract>

Ex-Ante Life Cycle Assessment Framework and Application to a Nano-Reinforced Biopolymer Film Based on Mango Kernel

Ex-Ante Life Cycle Assessment Framework and Application to a Nano-Reinforced Biopolymer Film Based on Mango Kernel

Integrating life cycle assessment in early process development stage: The case of extracting starch from mango kernel

An important issue in the development of new processes is how to perform environmental impact assessments that support decisions at an early stage of process development. In this study, a methodological procedure was applied to insert life cycle assessment (LCA) in early design of two alternative processes (A and B) to extract starch from mango kernel. This procedure allowed to perform LCAs at technology readiness levels (TRL) 4 and 5 considering different functional units, production scales and alternative scenarios. The analysis of process A and B identified the phase of starch purification as one of the most impacting one. After modifications were implemented, the comparison of Process A with B showed that process A, characterized by extracting only starch, performed better in all situations, being recommended for the implementation in a pilot plant, the next level in the technology maturity scale. Process B still requires improvements to reduce the impacts on climate change and human toxicity. This case study showed reductions in energy and water use, and life cycle impacts, when moving production from lab to industrial scale, through simulation. It also showed that crop production should be considered when evaluating processes that use biomass waste as raw material. The lessons learned from this case study allowed the simplification and detail of the applied procedure for inserting LCA at early research stage. This procedure can be applied to perform ex-ante LCA of new processes.

Consequential ex-ante life cycle assessment on clinker production in the EU: How will the future influence its environmental impact?

The goal of this paper is to investigate how the environmental impact of clinker production might change in the future. This is assessed by the use of a consequential ex-ante life cycle assessment in which the changes to both the fore- and background system are taken into account. For the background system the focus is the electricity and fuel market. Cornerstone scenarios where developed using projections found in literature to estimate future trends. These scenarios consist of a reference scenario and two climate goal scenarios, one for clinker and one for energy. The climate goal scenarios are further divided up in pathways to reach the climate goal. Results indicate that the environmental impact of clinker production could be reduced by a factor of five in comparison with its current impact, going from 0.21 points in the reference scenario in this decade to as low as 0.04 in the other timeperiods and scenarios when using ReCiPe's single weighted score. This reduction is mainly a result of the introduction of carbon capture and the electrification of kilns. Results also showed that because of the increased electricity use of the cement sector, the environmental impact of clinker production becomes very sensitive to evolutions in the electricity sector.

Circular economy in the agro-industry: Integrated environmental assessment of dairy products

Bio-circular strategies to improve production and consumption can be the answer to decrease the current environmental pressure of the dairy sector. Environmental impacts are related to the extensive fodder production with intense use of fertilizers, greenhouse gasses emission from cattle and fossil fuels. To understand and measure the burdens of a dairy production chain (particularly buffalo mozzarella cheese, a specialty of the Campania Region, Italy), the Life Cycle Assessment and Emergy accounting Applied Framework (LEAF) was applied. Many studies evaluated dairy systems using single methods, which are unable to capture all sustainable perspectives. The LEAF evaluation encompasses an Ex-ante LCA (Life Cycle Assessment) to identify the hotspots and suggest feasible improved scenarios of the investigated case study. Followed by EMA (EMergy Accounting) and Ex-post LCA applications, LEAF assures the feasibility of the proposed solutions and verifies the reduction of the environmental burdens towards increased sustainability. Two different scenarios were built based on the identified hotspots (cleaning products and electricity): (i) a technological improvement (dealing with cleaning processes methods), (ii) an eco-efficiency perspective (fossil energy replaced with renewable alternatives). Additionally, viewpoint shifting scenarios based on (iii) different allocation procedures were proposed to discuss crucial methodological issues. Results showed that technological improvements provide the best environmental performance, with lower emissions and better Emergy indicators, and better work conditions. However, the use of a more renewable electricity mix can deliver similar environmental gains. The change of perspective in the last scenario highlighted that multi-output issues should be carefully treated to avoid misleading results.