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- Ahmadi Moghaddam, Elham, et al.
(author)
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Exploring the potential for biomethane production by willow pyrolysis using life cycle assessment methodology
- 2019
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In: Energy, Sustainability and Society. - : Springer Science and Business Media LLC. - 2192-0567. ; 9
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Journal article (peer-reviewed)abstract
- BackgroundBiomethane, as a potential substitute for natural gas, reduces the use of fossil-based sources, promoting bioenergy applications. Biomethane for energy use can be produced using a variety of biomass types and technologies. Biomethane from farmland crops is currently produced by anaerobic digestion (AD) of energy crops, which is a biological treatment of organic material resulting in biomethane and digestate. Recently, thermochemical conversion technologies of biomass to biomethane have gained attention. Pyrolysis is a thermochemical process whereby woody biomass is converted to fuel gas and biochar. This study assessed the land use efficiency of producing biomethane through a maize-based AD system compared with switching to a willow-based biomethane system using pyrolysis as an emerging technology. The energy performance and climate impact of the two pathways were assessed from a land use perspective, using life cycle assessment methodology. The entire technical system, from biomass production to delivery of biomethane as the end product, was included within the analysis. The study also investigated how the climate impact was affected when biochar was applied to soil to act as a soil amendment and carbon sequestration agent or when biochar was used as an energy source.ResultsPyrolysis of willow had a higher external energy ratio and climate mitigation effect than maize-based AD as a result of lower primary energy inputs and lower methane loss in the pyrolysis process and upgrading units. Furthermore, the biochar from willow pyrolysis, when used as a soil amendment or energy source, contributed significantly to the climate impact mitigation potential in both cases. Substituting fossil gas with biomethane gave a considerable reduction in climate impact in all scenarios, especially in the case of willow pyrolysis. The willow pyrolysis system acted as a carbon sink, resulting in a negative climate impact, counteracting global warming.ConclusionFrom a land use perspective, the transition from maize-based AD to a willow-based pyrolysis system for biomethane production could be beneficial regarding the energy performance and climate impact. Application of biochar to the soil in the willow scenario contributed significantly to counteracting emissions of greenhouse gases.
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| 2. |
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| 3. |
- Ericsson, Niclas, et al.
(author)
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Climate impact and energy efficiency from electricity generation through anaerobic digestion or direct combustion of short rotation coppice willow
- 2014
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 132, s. 86-98
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Journal article (peer-reviewed)abstract
- Short rotation coppice willow is an energy crop used in Sweden to produce electricity and heat in combined heat and power plants. Recent laboratory-scale experiments have shown that SRC willow can also be used for biogas production in anaerobic digestion processes.Here, life cycle assessment is used to compare the climate impact and energy efficiency of electricity and heat generated by these measures. All energy inputs and greenhouse gas emissions, including soil organic carbon fluxes were included in the life cycle assessment. The climate impact was determined using time-dependent life cycle assessment methodology.Both systems showed a positive net energy balance, but the direct combustion system delivered ninefold more energy than the biogas system. Both systems had a cooling effect on the global mean surface temperature change. The cooling impact per hectare from the biogas system was ninefold higher due to the carbon returned to soil with the digestate.Compensating the lower energy production of the biogas system with external energy sources had a large impact on the result, effectively determining whether the biogas scenario had a net warming or cooling contribution to the global mean temperature change per kWh of electricity. In all cases, the contribution to global warming was lowered by the inclusion of willow in the energy system. The use of time-dependent climate impact methodology shows that extended use of short rotation coppice willow can contribute to counteract global warming. (C) 2014 Elsevier Ltd. All rights reserved.
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| 4. |
- Ericsson, Niclas, et al.
(author)
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The effect of Soil Organic Carbon and the Time Frame on the GWP in a Short Rotation Coppice LCA
- 2012
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In: European Biomass Conference and Exhibition Proceedings. - 2282-5819. ; , s. 2235-2237
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Conference paper (other academic/artistic)abstract
- The energy delivered from short rotation coppice willow is expected to increase in Sweden. Expanding the area of willow will lead to land use changes which may affect soil organic carbon stocks. Many previous life cycle assessments on climate impact of willow exclude soil organic stock changes. These studies also use different system time frames, depending on how long the plantation is expected to prevail. In the present work the global warming potential was assessed for a short rotation coppice willow system established on a 20-year old fallow, including and excluding soil organic carbon, using different time frames and functional units. The global warming potential using a time frame of 24 years was -16.3 kg CO2-eq • GJ-1 including soil organic carbon compared to 6.7 kg CO2-eq • GJ-1 when excluded, showing the importance to consider soil organic carbon changes in life cycle assessments of short rotation coppice when a land use change take place. The time frame and the functional unit chosen were also shown to have an influence on the climate impact.
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| 5. |
- Ericsson, Niclas, et al.
(author)
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Time-dependent climate impact and energy efficiency of combined heat and power production from short-rotation coppice willow using pyrolysis or direct combustion
- 2017
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In: Global Change Biology Bioenergy. - : Blackwell Publishing Ltd. - 1757-1693 .- 1757-1707. ; 9:5, s. 876-890
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Journal article (peer-reviewed)abstract
- A life cycle assessment of a Swedish short-rotation coppice willow bioenergy system generating electricity and heat was performed to investigate how the energy efficiency and time-dependent climate impact were affected when the feedstock was converted into bio-oil and char before generating electricity and heat, compared with being combusted directly. The study also investigated how the climate impact was affected when part of the char was applied to soil as biochar to act as a carbon sequestration agent and potential soil improver. The energy efficiencies were calculated separately for electricity and heat as the energy ratios between the amount of energy service delivered by the system compared to the amount of external energy inputs used in each scenario after having allocated the primary energy related to the inputs between the two energy services. The energy in the feedstock was not included in the external energy inputs. Direct combustion had the highest energy efficiency. It had energy ratios of 10 and 36 for electricity and heat, respectively. The least energy-efficient scenario was the pyrolysis scenario where biochar was applied to soils. It had energy ratios of 4 and 12 for electricity and heat, respectively. The results showed that pyrolysis with carbon sequestration might be an option to counteract the current trend in global warming. The pyrolysis system with soil application of the biochar removed the largest amount of CO2 from the atmosphere. However, compared with the direct combustion scenario, the climate change mitigation potential depended on the energy system to which the bioenergy system delivered its energy services. A system expansion showed that direct combustion had the highest climate change mitigation potential when coal or natural gas were used as external energy sources to compensate for the lower energy efficiency of the pyrolysis scenario.
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| 6. |
- Ericsson, Niclas, et al.
(author)
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Time-dependent climate impact of a bioenergy system - methodology development and application to Swedish conditions
- 2013
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In: GCB Bioenergy. - : Wiley. - 1757-1693 .- 1757-1707. ; 5, s. 580-590
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Journal article (peer-reviewed)abstract
- The area of dedicated energy crops is expected to increase in Sweden. This will result in direct land use changes, which may affect the carbon stocks in soil and biomass, as well as yield levels and the use of inputs. Carbon dioxide (CO2) fluxes of biomass are often not considered when calculating the climate impact in life cycle assessments (LCA) assuming that the CO2 released at combustion has recently been captured by the biomass in question. With the extended time lag between capture and release of CO2 inherent in many perennial bioenergy systems, the relation between carbon neutrality and climate neutrality may be questioned. In this paper, previously published methodologies and models are combined in a methodological framework that can assist LCA practitioners in interpreting the time-dependent climate impact of a bioenergy system. The treatment of carbon differs from conventional LCA practice in that no distinction is made between fossil and biogenic carbon. A time-dependent indicator is used to enable a representation of the climate impact that is not dependent on the choice of a specific characterization time horizon or time of evaluation and that does not use characterization factors, such as global warming potential and global temperature potential. The indicator used to aid in the interpretation phase of this paper is global mean surface temperature change (T-s(n)). A theoretical system producing willow for district heating was used to study land use change effects depending on previous land use and variations in the standing biomass carbon stocks. When replacing annual crops with willow this system presented a cooling contribution to T-s(n). However, the first years after establishing the willow plantation it presented a warming contribution to T-s(n). This behavior was due mainly to soil organic carbon (SOC) variation. A rapid initial increase in standing biomass counteracted the initial SOC loss.
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| 7. |
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| 8. |
- Zhang, Shan, et al.
(author)
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Life cycle assessment of an all-organic battery: Hotspots and opportunities for improvement
- 2022
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 337
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Journal article (peer-reviewed)abstract
- Organic batteries are emerging as a potential sustainable power source for future flexible devices. Using life cycle assessment, this study analyzed the environmental impacts from the synthesis process for an all-organic battery with conducting redox polymers as active materials for electrodes. Synthesis steps were modeled and analyzed in detail, based on actual laboratory processes data for electrodes, and industrial data for other battery components. Complete and transparent inventory data are presented and can be used in future environmental assessments. The organic battery studied is still at an early development stage, so environmental hotspots and potential improvements in the synthesis processes were examined. For selected environmental impact categories, the life cycle assessment results showed that synthesis of cathode backbone was the major contributor (47-63%) to the environmental impacts of the all-organic battery cell among different synthesis stages, because of a long synthesis route associated with high solvent usage. Solvents (e.g., dichloromethane), catalysts (e.g., copper oxide, Pd (PPh3)4), zinc, and waste treatment processes were important single contributors to the total impacts. The results reveal significant potential for improvement by optimizing the amount of solvents needed to synthesize battery electrodes. Changing treatment methods for laboratory waste solvents can also strongly influence the results.
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| 9. |
- Zhang, Shan, et al.
(author)
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Prospective life cycle assessment of a flexible all-organic battery
- 2022
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In: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 373
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Journal article (peer-reviewed)abstract
- Strong interest from researchers and industry is accelerating development of flexible energy storage technologies for future flexible devices. It is critical to consider the environmental perspective in early development of new emerging technologies. In this study, cradle-to-factory gate prospective life cycle assessment (LCA) was per-formed on production of an all-organic battery with conductive redox polymers as electrode material. To gain a better understanding of the environmental performance of the all-organic battery, a flexible lithium-ion (Li-ion) battery with lithium titanate oxide and lithium cobalt oxide as electrode active materials was modeled as reference. Main environmental impacts of the all-organic battery were attributable to anode and cathode pro-duction, with electrode backbones being the main contributors. Solvents, catalysts, waste treatment, energy, and bromine were key individual contributors. Comparison with the flexible Li-ion battery indicated inferior envi-ronmental performance of the all-organic battery due to its relatively low specific energy (Wh/kg) and large amount of materials needed for production of its electrode backbones. Sensitivity analysis showed that changing scaling-up parameters and the production route of 3,4-ethylenedioxythiophene (a precursor of electrode back-bones) strongly influenced the results. In order to lower the environmental impacts of the all-organic battery, future research should focus on designing a short production chain with lower material inputs of electrode backbones, increasing battery cycle life, and improving the specific energy of the battery. In addition, relevant recommendations were provided for prospective LCAs of upscaled systems.
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