| 31. |
- Hermansson, Frida, 1988, et al.
(författare)
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Environmental Challenges and Opportunities of Lignin
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Lignin is the most abundant bio-polymer on Earth, gluing the cellulose and hemicellulose fibers together in the tree stem and providing stiffness. Lignin is presently mostly available in side streams of biorefineries and pulp mills (e.g. in the black liquor of the Kraft pulp mill). It is almost always combusted for internal energy use at the plant due to its present low market value. Though lignin can be extracted and valorized, for example via acidification followed by precipitation and membrane filtration or by solvent extraction, this is seldom done today. Nevertheless, lignin is gradually being considered an interesting raw material for various products and applications, ranging from biofuels to carbon fibers. However, in environmental life cycle assessments of lignin-based products, the environmental impacts of lignin production typically have not been accounted for with the rational that lignin is a waste that needs to be taken care off.This argument will no longer be valid when lignin extraction processes are further developed and various markets for lignin open up. Conducting a life cycle assessment of lignin production is complicated. As lignin is a product of a multi-output process, there will be inherent challenges regarding the choice of system expansion or how to allocate environmental impacts to this product and to other products. Allocation based on economic values is particularly challenging as the market price of lignin and of other products from the process is the basis for allocating impacts, and the future market development for lignin is still rather unexplored and uncertain. The same challenge can be applied to system expansion, as what is being substituted could change in the future. The aim of the presented study is to provide guidance on how to better assess lignin production in life cycle assessments. The cradle-to-gate environmental impacts of 1 kg of lignin from a Kraft pulp mill is assessed. Different allocation methods as well system expansion by substitution will be applied to the multi-output process to assess and illustrate what influence these will have on the final environmental impacts of the lignin.
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| 32. |
- Hermansson, Frida, 1988, et al.
(författare)
-
Life cycle assessment of lignin-based carbon fibres
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- As vehicle manufacturers attempt to decrease the weight of their products, and consequently the fuel consumption during the use phase, carbon fibre reinforced polymers, CFRPs, are becoming more common. However, as the carbon fibre production route has proven to be very energy intensive, CFRP may not perform as well as conventional materials such as steel when using an environmental life cycle perspective. Carbon fibres are usually made from polyacrylonitrile, PAN, a fossil-based polymer. Research has shown that a possible route to reduce the environmental impact from carbon fibres is to replace PAN with a bio-based alternative, such as lignin. Lignin is a main by-product of many biorefinery processes that use ligno-cellulosic material as feedstock. A switch to lignin instead of PAN could reduce the environmental impact of the carbon fibres, decrease the dependence on oil as well as reduce the cost of the carbon fibres. This paper, which is a part of Frida Hermansson PhD-project will include findings from the life cycle assessment of lignin-based carbon fibres as well as discuss how different allocation methods will have effect on the final results. The production of lignin-based carbon fibres was assessed using life cycle assessment. The functional unit was 1 kg of carbon fibres at the factory gate. Results show that replacing PAN with lignin as a precursor fibre material could decrease the energy consumption as well as climate impact. However, as lignin is bio-based, land use will increase. The impact results for the lignin-based carbon fibres largely depend on how much of the environmental impact is allocated to lignin for a given biorefinery process. Lignin’s relatively low price in combination with its large quantity leads to the economic allocation method being the most favourable. Lignin has long been considered a waste product, but as the demand for lignin increases so should the price. This means that the type of allocation applied will have significant influence on the environmental impacts of lignin-based carbon fibres.
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| 33. |
- Hermansson, Frida, 1988, et al.
(författare)
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Prospective screening life cycle assessment of a sodium-ion hybrid supercapacitor
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Hybrid supercapacitors combine batteries' energy density with capacitors' power density. They can extend the lifetime of an electrical vehicle battery by reducing the number and depth of the charge/discharge cycles and by enhancing the battery’s power capacity. Traditionally, hybrid supercapacitors contain lithium, a geochemically scarce metal. To mitigate a future lithium shortage, measures could be taken to substitute lithium with more abundant materials. One option is sodium-ion hybrid supercapacitors. In this report, we assess the climate and mineral resource scarcity impacts of manufacturing a sodium hybrid supercapacitor by means of life cycle assessment. The goal is to identify hotspots to aid researchers, developers, and potential manufacturers in making environmentally benign design choices. The considered sodium-ion hybrid supercapacitor is not yet produced at large scale but only in laboratories. To address this, we scale up the production process to an industrial scale using frameworks available in the literature. Results show that the activated carbon electrode is responsible for most of the environmental impact due to the use of nitric acid in processing the activated carbon. If nitric acid could be replaced, recycled, or reduced, this would lower the environmental impact considerably. Additionally, we provide guidance on how to scale up the mass of the sodium-ion hybrid supercapacitor to meet the requirement of a vehicle. This upscaling also means that the results can be used in screening assessments by vehicle developers interested in how the sodium-ion hybrid supercapacitor could influence the environmental impact of their vehicle.
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| 34. |
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| 35. |
- Jerome, Adeline, 1994, et al.
(författare)
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Environmental sustainability of high voltage motors: do better efficiency and repair lead to improved environmental impact?
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Various circular economy (CE) strategies, for instance lifetime extension by repair or reuse, have been suggested to improve products’ environmental performance. The literature emphasises the need to better understand the consequences of those CE strategies with assessment tools such as life cycle assessment (LCA). From previous assessments, Böckin et al. (2020) identifies energy use reduction and use extension by maintenance, repair or remanufacturing as relevant CE strategies for durable and active products. However, this conclusion is based on assessments of small- and medium-size electronic products, leaving out more durable and more energy consuming bigger products. In this study, the implementation of two CE strategies, energy use reduction and use extension by repair, is explored for high voltage (HV) motors delivering 135GWh per year over at least 20 years. Electric motors are prominent active products, representing 50% of the electricity consumption in Europe. Even in small numbers, HV motors represent a significant share of this consumption due to their more intensive use and high output power. Two main HV motor technologies exist: induction motors (IM) and synchronous motors (SM), which are more energy efficient. Both are often used until failure, which frequently occurs in stator windings but could be repaired by rewinding at the expense of a slight decrease in efficiency. This study aims to compare the life-cycle environmental impact of the two motor technologies and to explore their lifetime extension by repair in comparison to their replacement. For each motor technology, a cradle-to-grave LCA is performed for global warming and mineral and metal resource depletion impact categories. The IM has an efficiency of 97.3%, the SM an efficiency of 98.3% and both are run 20 years. Results show that the impact of electricity consumption during use is dominant. Besides, the SM has a lower environmental impact than the IM. In term of resource depletion, SM manufacturing is more impactful but lower energy losses during use compensate for the difference. Repair is modelled with the production of a new stator winding and a decrease in efficiency of 0.7%. Three scenarios are compared. The IM is initially used for 20 years, and an additional 10 years of use is provided by either 1) replacing with an IM with the same efficiency, 2) replacing with the SM, or 3) repair by rewinding. LCA results show that the additional energy losses after repair in scenario 3 offset the gain from avoiding the production of a new motor compared to scenarios 1 and 2. This study shows that the long lifetime and high energy requirements of HV motors lead the energy efficiency to be an essential factor for the life-cycle environmental performance. Choosing and maintaining high energy efficiency is key in this situation, especially for lifetime extension strategies to be beneficial for the product environmental performance. Reference: Böckin et al. (2020), How product characteristics can guide measures for resource efficiency. Resources, Conservation and Recycling 154, 104582.
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| 36. |
- Jerome, Adeline, 1994, et al.
(författare)
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Is repair of energy using products environmentally beneficial? The case of high voltage electric motors
- 2023
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Ingår i: Resources, Conservation and Recycling. - 0921-3449 .- 1879-0658. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Repair is advocated as a circular strategy to improve the environmental performance of products. Whether this holds for very long-lived and energy intensive products has not been addressed. This study compares environmental impacts of two high voltage motors of different energy efficiency and assesses their use extension by repair with life cycle assessment (LCA). Due to high energy use, long lifetime and intensive use, the use phase dominates all environmental impacts, even resource depletion. Therefore, a higher energy efficiency is more beneficial than extending the use by repair, and if the energy efficiency is slightly reduced, the repair is not beneficial. Therefore, product requirements and users and manufacturers of such products should ensure designs with high energy efficiency rather than making the product repairable. Finally, the results highlight the importance of including resource use from electricity production and transmission in LCA of the use extension of energy using products.
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| 37. |
- Jerome, Adeline, 1994, et al.
(författare)
-
Repair for high-voltage electric motors energy efficiency vs resource use?
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Electric motors in the industry represent 69% of the industrial electricity consumption in Europe. Even if few in number, high voltage (HV) motors represent a significant share of this consumption due to their more intensive use and high output power. Two main HV motor technologies exist: induction motors (IM) and synchronous motors (SM), of which the latter are more energy efficient. Improving energy efficiency as well as use extension by maintenance, repair or remanufacturing have been identified as relevant circular economy strategies for improving the environmental performance of such active and durable products. However, the assessments performed focus on small- and medium-size electronic products, leaving out bigger products that are more durable and more energy consuming such as HV motors. Those motors are often used until failure, which frequently occurs in stator windings, and which could be repaired by rewinding at the expense of a slight decrease in efficiency. However, other use extension strategies such as reuse and remanufacturing are hindered by the customization of HV motors to their specific use. Finding an appropriate set-up for a second use is difficult for such motors and it is therefore performed seldom. The aim of this study is to compare the life-cycle environmental impact of lifetime extension by repair for the two motor technologies in comparison to their replacement.
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| 38. |
- Jerome, Adeline, 1994, et al.
(författare)
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When is repair environmentally beneficial? The case of high-voltage electric motors
- 2023
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Use extension by repair is a circular economy (CE) strategy that has been advocated to improve products’ environmental performance and resource efficiency. Previous studies have shown that this does not necessarily hold for energy-using products, for instance, when a more energy-efficient product is available for replacement. The requirements for use extension to be beneficial have been found to vary with the product and its use conditions. However, resource depletion is seldom discussed, and the case of very long-lived and energy-intensive products has not been addressed yet. An example of such an energy-intensive product is high-voltage (HV) electric motors, typically used for more than 20 years and in operation for 50 weeks a year full time. Electric motors represent 50% of the electricity consumption in Europe and despite being few, HV motors represent a significant share of this consumption. The two HV motor designs, induction motors (IM) and synchronous motors (SM), are often used until failure, commonly occurring in stator windings which could be repaired but with the risk of affecting energy efficiency. This work aims to provide recommendations on important aspects for use extension to be environmentally beneficial for long-lived and energy-intensive products. Cradle-to-grave LCAs are performed for global warming and mineral resource depletion to compare (1) the two motor designs and (2) each motor with and without use extension through repair. The motors are chosen to deliver the same output of 16 MW and the functional unit is set to one year of operation. The IM has an energy efficiency of 97.3%, the SM has an efficiency of 98.3% and both are run for 20 years. The additional use time and the efficiency reduction after the repair are left as varying parameters between 1 and 20 years and between 0 and 1% respectively. Results show that, due to high energy use and long lifetime, the impact of electricity use during motor use is dominant for both global warming and resource depletion. This dominance remains with different electricity mixes, including in a scenario with hydroelectricity only. For resource depletion, it is due to copper in transmission lines and resources for electricity production (e.g., uranium from nuclear energy production). The dominance of the use phase results in energy efficiency being key to the environmental performance of HV motors. The more efficient design, the SM, results in lower impacts than the IM in both impact categories. In terms of resource depletion, SM manufacturing is more impactful but lower energy losses during use compensate for the difference. Besides, additional energy losses from a small energy efficiency reduction offset the gain from the repair for both global warming and resource depletion. The gain from the use extension by repair is small compared to the benefit of choosing the more efficient design. Choosing and maintaining high energy efficiency is key for long-lived and energy-intensive products’ environmental performance due to their high energy requirements and long lifetime. Thus, efforts should be channelled on ensuring high energy efficiency by design and after repair. This is relevant for both policy-making and manufacturers or users when prioritising strategies for improving products’ environmental performance. Finally, as conclusions are similar for global warming and resource depletion, this work demonstrates the importance of including resource use from electricity production and transmission when exploring the use extension of energy-using products.
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| 39. |
- Johansson, Björn, 1975, et al.
(författare)
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Evaluation and Calculation of Dynamics in Environmental Impact Assessment
- 2013
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Ingår i: IFIP Advances in Information and Communication Technology. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1868-4238 .- 1868-422X. - 9783642403514 ; 397:1, s. 135-141
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Konferensbidrag (refereegranskat)abstract
- In ten years customers will select products not only based on price and quality but also with strong regard to the product value environmental footprint, including for example the energy consumed. Customers expect transparency in the product realization process, where most products are labeled with their environmental footprint. Vigorous companies see this new product value as an opportunity to be more competitive. In order to effectively label the envi-ronmental impact of a product, it is pertinent for companies to request the envi-ronmental footprint of each component from their suppliers. Hence, companies along the product lifecycle require a tool, not only to facilitate the computing of the environmental footprint, but also help reduce/balance the environmental impact during the lifecycle of the product. This paper proposes to develop a procedure that companies will use to evaluate, improve and externally advertise their product’s environmental footprint to customers.
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| 40. |
- Johansson, Björn, 1975, et al.
(författare)
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Power Level Sampling of Metal Cutting Machines for Data Representation in Discrete Event Simulation
- 2015
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 53:23, s. 7060-7070
-
Tidskriftsartikel (refereegranskat)abstract
- An extension to the application area for discrete event simulation (DES) has been ongoing since the last decade and focused only on economic aspects to include ecologic sustainability. With this new focus, additional input parameters, such as electrical power consumption of machines, are needed. This paper aim at investigating how NC machine power consumption should be represented in simulation models of factories. The study includes data-sets from three different factories. One factory producing truck engine blocks, one producing brake disc parts for cars and one producing forklift components. The total number of data points analysed are more than 2,45,000, where of over 1,11,000 on busy state for 11 NC machines. The low variability between busy cycles indicates that statistical representations are not adding significant variability. Furthermore, results show that non-value-added activities cause a substantial amount of the total energy consumption, which can be reduced by optimising the production flow using dynamic simulations such as DES.
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