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Azzi, E. S., Karltun, E. & Sundberg, C. (2022). Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden. Biochar, 4(1), Article ID 18.
Open this publication in new window or tab >>Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden
2022 (English)In: Biochar, ISSN 2524-7972, E-ISSN 2524-7867, Vol. 4, no 1, article id 18Article in journal (Refereed) Published
Abstract [en]

Biochar is a material derived from biomass pyrolysis that is used in urban applications. The environmental impacts of new biochar products have however not been assessed. Here, the life cycle assessments of 5 biochar products (tree planting, green roofs, landscaping soil, charcrete, and biofilm carrier) were performed for 7 biochar supply-chains in 2 energy contexts. The biochar products were benchmarked against reference products and oxidative use of biochar for steel production. Biochar demand was then estimated, using dynamic material flow analysis, for a new city district in Uppsala, Sweden. In a decarbonised energy system and with high biochar stability, all biochar products showed better climate performance than the reference products, and most applications outperformed biomass use for decarbonising steel production. The climate benefits of using biochar ranged from - 1.4 to - 0.11 tonne CO2-eq tonne(-1) biochar in a decarbonised energy system. In other environmental impact categories, biochar products had either higher or lower impacts than the reference products, depending on biochar supply chain and material substituted, with trade-offs between sectors and impact categories. However, several use-phase effects of biochar were not included in the assessment due to knowledge limitations. In Uppsala's new district, estimated biochar demand was around 1700 m(3) year(-1) during the 25 years of construction. By 2100, 23% of this biochar accumulated in landfill, raising questions about end-of-life management of biochar-containing products. Overall, in a post-fossil economy, biochar can be a carbon dioxide removal technology with benefits, but biochar applications must be designed to maximise co-benefits.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Biochar, Carbon dioxide removal, Urban areas, Bioeconomy, Life cycle assessment, Material flow analysis
National Category
Environmental Sciences Other Environmental Engineering
Identifiers
urn:nbn:se:kth:diva-310236 (URN)10.1007/s42773-022-00144-3 (DOI)000766159100001 ()2-s2.0-85126205231 (Scopus ID)
Note

QC 20220325

Available from: 2022-03-25 Created: 2022-03-25 Last updated: 2024-04-04Bibliographically approved
Kätterer, T., Roobroeck, D., Kimutai, G., Karltun, E., Nyberg, G., Sundberg, C. & de Nowina, K. R. (2022). Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya. Agronomy for Sustainable Development, 42(4), Article ID 63.
Open this publication in new window or tab >>Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya
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2022 (English)In: Agronomy for Sustainable Development, ISSN 1774-0746, E-ISSN 1773-0155, Vol. 42, no 4, article id 63Article in journal (Refereed) Published
Abstract [en]

Despite efforts to increase agricultural production sustainably in sub-Saharan Africa, large gaps remain between actual and potential yield of food crops. Adding biochar to degraded cropland soils in the African tropics has significant potential to enhance crop productivity. Biochar-based farming can also mitigate climate change, through soil carbon storage. This study involved six smallholder farms at sites in eastern, central, and western Kenya that are characterized by different pedo-climatic conditions. We examined the response of non-fertilized and fertilized maize monoculture to three dosages of biochar that are realistic for domestic production by farmers at each of the sites over four growing seasons. Commonly available biomass wastes in each agro-ecosystem (coconut shells, coffee husks, maize cobs) were used as feedstock for biochar, which was applied at 1, 5, and 10 Mg ha−1 at the start of the experiment. Across seasons and fertilizer treatments, maize grain yield (dry matter) showed consistently positive responses, with an average increase of 1.0, 2.6, and 4.0 Mg ha−1, respectively, above the control for the three biochar application rates. Absolute responses of maize grain yield to specific biochar doses were similar across the four investigated seasons and replicate farms within sites, and uncorrelated to yield levels in the control treatment. Here, we show for the first time that yield response to biochar decreased with increasing application rate, indicating that it may be better to spread a given amount of biochar over a large area rather than concentrating it to a smaller area, at least when biochar is applied along plant rows at rates ≥1 Mg ha−1, as in our experiment. This study demonstrated that application of biochar, locally produced from available biomass residues, is a promising approach to enhance agricultural production and carbon storage on smallholder farms under a wide range of pedo-climatic conditions in Kenya. 

Place, publisher, year, edition, pages
Springer-Verlag Italia s.r.l., 2022
Keywords
Agricultural intensification, Biochar farming, Fertilizer use, Food security, Maize production, Smallholder farmers, Soil carbon sequestration, Soil fertility, Sub-Saharan Africa, agricultural production, alternative agriculture, biochar, biomass, carbon storage, coffee, fertilizer application, maize, monoculture, smallholder, soil carbon, yield response, Kenya
National Category
Agricultural Science Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-325067 (URN)10.1007/s13593-022-00793-5 (DOI)000815489000003 ()2-s2.0-85132913036 (Scopus ID)
Note

QC 20230328

Available from: 2023-03-28 Created: 2023-03-28 Last updated: 2023-09-21Bibliographically approved
Azzi, E. S., Karltun, E. & Sundberg, C. (2021). Assessing the diverse environmental effects of biochar systems: An evaluation framework. Journal of Environmental Management, 286, Article ID 112154.
Open this publication in new window or tab >>Assessing the diverse environmental effects of biochar systems: An evaluation framework
2021 (English)In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 286, article id 112154Article in journal (Refereed) Published
Abstract [en]

Biochar has been recognised as a carbon dioxide removal (CDR) technology. Unlike other CDR technologies, biochar is expected to deliver various valuable effects in e.g. agriculture, animal husbandry, industrial processes, remediation activities and waste management. The diversity of biochar side effects to CDR makes the systematic environmental assessment of biochar projects challenging, and to date, there is no common framework for evaluating them. Our aim is to bridge the methodology gap for evaluating biochar systems from a life-cycle perspective. Using life cycle theory, actual biochar projects, and reviews of biochar research, we propose a general description of biochar systems, an overview of biochar effects, and an evaluation framework for biochar effects. The evaluation framework was applied to a case study, the Stockholm Biochar Project. In the framework, biochar effects are classified according to life cycle stage and life cycle effect type; and the biochar?s end-of-life and the reference situations are made explicit. Three types of effects are easily included in life cycle theory: changes in biosphere exchanges, technosphere inputs, and technosphere outputs. For other effects, analysing the cause-effect chain may be helpful. Several biochar effects in agroecosystems can be modelled as future productivity increases against a reference situation. In practice, the complexity of agroecosystems can be bypassed by using empirical models. Existing biochar life cycle studies are often limited to carbon footprint calculations and quantify a limited amount of biochar effects, mainly carbon sequestration, energy displacements and fertiliser-related emissions. The methodological development in this study can be of benefit to the biochar and CDR research communities, as well as decision-makers in biochar practice and policy.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
Biochar, Carbon dioxide removal, Side effect, Avoided burden, Life cycle thinking, Life cycle assessment
National Category
Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-293464 (URN)10.1016/j.jenvman.2021.112154 (DOI)000634990300004 ()33609929 (PubMedID)2-s2.0-85101462906 (Scopus ID)
Note

QC 20210426

Available from: 2021-04-26 Created: 2021-04-26 Last updated: 2022-06-25Bibliographically approved
Gustafsson, K., Sadegh-Vaziri, R., Grönkvist, S., Levihn, F. & Sundberg, C. (2021). BECCS with combined heat and power: Assessing the energy penalty. International Journal of Greenhouse Gas Control, 108, Article ID 103248.
Open this publication in new window or tab >>BECCS with combined heat and power: Assessing the energy penalty
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2021 (English)In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 108, article id 103248Article in journal (Refereed) Published
Abstract [en]

Bio-energy with carbon capture and storage (BECCS) is widely recognised as an important carbon dioxide removal technology. Nevertheless, BECCS has mostly failed to move beyond small-scale demonstration units. One main factor is the energy penalty incurred on power plants. In previous studies, this penalty has been determined to be 37.2 %?48.6 % for the amine capture technology. The aim of this study is to quantify the energy penalty for adding the hot potassium carbonate (HPC) capture technology to a biomass-fired combined heat and power (CHP) plant, connected to a district heating system. In this context, the energy driving the capture process is partly recovered as useful district heating. Therefore, a modified energy penalty is proposed, with the inclusion of recovered heat. This inclusion is especially meaningful if the heat has a substantial monetary value. The BECCS system is examined using thermodynamic analysis, coupled with modelling of the capture process in Aspen PlusTM. Model validation is performed with data from a BECCS test facility. The results of this study show that the modified energy penalty is in the range of 2%?4%. These findings could potentially increase the attractiveness of BECCS as a climate abatement option in a district heating CHP setting.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
Bio-energy with carbon capture and storage, (BECCS), CO2 capture, Combined heat and power, Energy penalty, Chemical absorption, (K2CO3), Modelling and simulation
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-295830 (URN)10.1016/j.ijggc.2020.103248 (DOI)000647797900001 ()2-s2.0-85104129543 (Scopus ID)
Note

Correction in: International Journal of Greenhouse Gas Control, Volume 112, December 2021. DOI: 10.1016/j.ijggc.2021.103433, Scopus: 2-s2.0-85114710943, QC 20220502

Available from: 2021-05-28 Created: 2021-05-28 Last updated: 2022-06-25Bibliographically approved
Papageorgiou, A., Henrysson, M., Nuur, C., Sinha, R., Sundberg, C. & Vanhuyse, F. (2021). Mapping and assessing indicator-based frameworks for monitoring Circular Economy development at the city-level. Sustainable cities and society, 75, Article ID 103378.
Open this publication in new window or tab >>Mapping and assessing indicator-based frameworks for monitoring Circular Economy development at the city-level
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2021 (English)In: Sustainable cities and society, ISSN 2210-6707, Vol. 75, article id 103378Article in journal (Refereed) Published
Abstract [en]

The transition towards a circular economy (CE) is increasingly recognized as a promising pathway to tackle pressing sustainability challenges at the city-level. Indicator-based frameworks, that is, integrated systems of indicators, are considered as useful tools for monitoring this transition. Yet, studies that map and assess such frameworks are scanty. This article addresses this gap by assessing 15 indicator-based frameworks applicable to measure circularity at the city-level. The identified frameworks were assessed using eight criteria (transparency, stakeholder engagement, effective communication, ability to track temporal changes, applicability, alignment with CE principles, validity and relevance to sustainable development). Additionally, 12 validity requirements were defined to assess to what extent the indicators in the frameworks reflect CE aspects. The assessment reveals a wide variation regarding the extent to which the frameworks match the criteria with none of them satisfying all. In addition, in terms of validity criterion, none includes indicators that fulfill all the validity requirements. Furthermore, most frameworks consist mainly of environmental indicators and only three include indicators reflecting aspects related to the four pillars of sustainable development (environmental, social, economic and governance). Further research could develop a standardized framework for measuring circularity at the city-level and improving existing frameworks.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
Circular cities, Circularity, Indicators, indicators, Metrics, Monitoring and evaluation, Sustainable urban development
National Category
Economic Geography
Identifiers
urn:nbn:se:kth:diva-302983 (URN)10.1016/j.scs.2021.103378 (DOI)000728571100006 ()2-s2.0-85116134733 (Scopus ID)
Funder
Vinnova, 2019-03237
Note

QC 20211213

Available from: 2021-10-03 Created: 2021-10-03 Last updated: 2022-06-25Bibliographically approved
Azzi, E. S., Karltun, E. & Sundberg, C. (2021). Small-scale biochar production on Swedish farms: A model for estimating potential, variability, and environmental performance. Journal of Cleaner Production, 280, Article ID 124873.
Open this publication in new window or tab >>Small-scale biochar production on Swedish farms: A model for estimating potential, variability, and environmental performance
2021 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 280, article id 124873Article in journal (Refereed) Published
Abstract [en]

Several small-scale pyrolysis plants have been installed on Swedish farms and uptake is increasing in the Nordic countries. Pyrolysis plants convert biomass to biochar for agricultural applications and syngas for heating applications. These projects are driven by ambitions of achieving carbon dioxide removal, reducing environmental impacts, and improving farm finances and resilience. Before policy support for on-farm pyrolysis projects is implemented, a comprehensive environmental evaluation of these systems is needed. Here, a model was developed to jointly: (i) simulate operation of on-farm energy systems equipped with pyrolysis units; (ii) estimate biochar production potential and its variability under different energy demand situations and designs; and (iii) calculate life cycle environmental impacts. The model was applied to a case study farm in Sweden. The farm's heating system achieved net carbon dioxide removal through biochar carbon sequestration, but increased its impact in several other environmental categories, mainly due to increased biomass throughput. Proper dimensioning of heat-constrained systems is key to ensure optimal biochar production, as biochar production potential of the case farm was reduced under expected climate change in Sweden. To improve the environmental footprint of future biochar systems, it is crucial that expected co-benefits from biochar use in agriculture are realised. The model developed here is available for application to other cases.

Place, publisher, year, edition, pages
Elsevier Ltd, 2021
Keywords
Biochar, Energy system modelling, Farm, Life cycle assessment, Potential, Pyrolysis, Agricultural robots, Agriculture, Carbon dioxide, Climate change, Environmental management, Life cycle, Carbon dioxide removal, Carbon sequestration, Constrained systems, Environmental evaluation, Environmental footprints, Environmental performance, Heating applications, Life-cycle environmental impact, Environmental impact
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-290824 (URN)10.1016/j.jclepro.2020.124873 (DOI)000603570700008 ()2-s2.0-85095768297 (Scopus ID)
Note

QC 20210323

Available from: 2021-03-23 Created: 2021-03-23 Last updated: 2022-06-25Bibliographically approved
Nilsson, J., Tidåker, P., Sundberg, C., Henryson, K., Grant, B., Smith, W. & Hansson, P.-A. -. (2020). Assessing the climate and eutrophication impacts of grass cultivation at five sites in Sweden. Acta Agriculturae Scandinavica - Section B
Open this publication in new window or tab >>Assessing the climate and eutrophication impacts of grass cultivation at five sites in Sweden
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2020 (English)In: Acta Agriculturae Scandinavica - Section B, ISSN 0906-4710, E-ISSN 1651-1913Article in journal (Refereed) Published
Abstract [en]

In this study, Life Cycle Assessment (LCA) methodology was combined with the agro-ecosystem model DNDC to assess the climate and eutrophication impacts of perennial grass cultivation at five different sites in Sweden. The system was evaluated for two fertilisation rates, 140 and 200 kg N ha−1. The climate impact showed large variation between the investigated sites. The largest contribution to the climate impact was through soil N2O emissions and emissions associated with mineral fertiliser manufacturing. The highest climate impact was predicted for the site with the highest clay and initial organic carbon content, while lower impacts were predicted for the sandy loam soils, due to low N2O emissions, and for the silty clay loam, due to high carbon sequestration rate. The highest eutrophication potential was estimated for the sandy loam soils, while the sites with finer soil texture had lower eutrophication potential. According to the results, soil properties and weather conditions were more important than fertilisation rate for the climate impact of the system assessed. It was concluded that agro-ecosystem models can add a spatial and temporal dimension to environmental impact assessment in agricultural LCA studies. The results could be used to assist policymakers in optimising use of agricultural land. 

Place, publisher, year, edition, pages
Taylor and Francis Ltd., 2020
Keywords
Carbon sequestration, DNDC model, greenhouse gas emissions, life cycle assessment (LCA), perennial cropping systems, soil N2O emissions
National Category
Soil Science
Identifiers
urn:nbn:se:kth:diva-284943 (URN)10.1080/09064710.2020.1822436 (DOI)000571299100001 ()2-s2.0-85091167167 (Scopus ID)
Note

QC 20201214

Available from: 2020-12-14 Created: 2020-12-14 Last updated: 2022-06-25Bibliographically approved
Sundberg, C., Karltun, E., Gitau, J. K., Katterer, T., Kimutai, G. M., Mahmoud, Y., . . . Sieber, P. (2020). Biochar from cookstoves reduces greenhouse gas emissions from smallholder farms in Africa. Mitigation and Adaptation Strategies for Global Change, 25(6), 953-967
Open this publication in new window or tab >>Biochar from cookstoves reduces greenhouse gas emissions from smallholder farms in Africa
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2020 (English)In: Mitigation and Adaptation Strategies for Global Change, ISSN 1381-2386, E-ISSN 1573-1596, Vol. 25, no 6, p. 953-967Article in journal (Refereed) Published
Abstract [en]

Biochar produced in cookstoves has the potential to contribute to negative carbon emissions through sequestration of biomass carbon while also providing other benefits for sustainable development, including provision of clean renewable energy and increased yields in tropical agriculture. The aim of the reported research was to estimate effects on food production, household energy access and life cycle climate impact from introduction of biochar-producing cookstoves on smallholder farms in Kenya. Participatory research on biochar production and use was undertaken with 150 Kenyan smallholder farming households. Gasifier cookstove functionality, fuel efficiency and emissions were measured, as well as biochar effects on agricultural yields after application to soil. Cookstoves provided benefits through reduced smoke, fuel wood savings and char production, but challenges were found related to labour for fuel preparation, lighting and refilling. On-farm trials with varying rates of biochar inputs, in combination with and without mineral fertilizers, have led to a sustained increase of maize yields following one-time application. The climate impact in a life cycle perspective was considerably lower for the system with cookstove production of biochar and use of biochar in agriculture than for current cooking practices. Climate benefits from biochar production and use are thus possible on smallholder farms in sub-Saharan Africa, through reduced use of biomass in cooking, reduced emissions of products of incomplete combustion and sequestration of stable biochar carbon in soils. Biochar-producing cookstoves can be implemented as a climate change mitigation method in rural sub-Saharan Africa. Successful implementation will require changes in cooking systems including fuel supply, as well as farming systems, which, in turn, requires an understanding of local socio-cultural conditions, including power relations and gender aspects.

Place, publisher, year, edition, pages
Springer Nature, 2020
Keywords
Biochar-producing gasifier stove, Bioenergy, Greenhouse gas, Woodfuel, Life cycle assessment
National Category
Environmental Sciences
Identifiers
urn:nbn:se:kth:diva-300794 (URN)10.1007/s11027-020-09920-7 (DOI)000541693200001 ()2-s2.0-85087043194 (Scopus ID)
Note

QC 20210917.

Available from: 2021-09-17 Created: 2021-09-17 Last updated: 2022-06-25Bibliographically approved
Papageorgiou, A., Ashok, A., Hashemi Farzad, T. & Sundberg, C. (2020). Climate change impact of integrating a solar microgrid system into the Swedish electricity grid. Applied Energy, 268, Article ID 114981.
Open this publication in new window or tab >>Climate change impact of integrating a solar microgrid system into the Swedish electricity grid
2020 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 268, article id 114981Article in journal (Refereed) Published
Abstract [en]

Microgrids are small-scale electricity networks that integrate distributed electricity generation with consumers and, potentially, with storage devices. There is growing interest in these systems, as they can offer solutions for electrification of remote areas, deployment of distributed renewable energy resources, and decarbonization of electricity supply. However, the potential benefits of microgrids in terms of climate change mitigation have not yet been thoroughly assessed. In this study, Life Cycle Assessment was performed to determine the climate change impact of integrating a solar microgrid system in western Sweden into the Swedish electricity grid. To determine whether replacement of grid electricity with electricity from the microgrid can lower greenhouse gas (GHG) emissions, average and marginal GHG emission factors (EFs) for electricity use were estimated with explicit spatial and temporal resolution, using historical data on electricity generation and trade, and life cycle EFs for electricity generation technologies. The assessment, with both marginal and average EFs, showed that integration of the microgrid into the Swedish electricity grid did not provide GHG emissions abatements, as the electricity from the microgrid displaced grid electricity with lower carbon intensity. It was found that a microgrid without batteries would have lower climate change impact, but would still fail to lower overall GHG emissions. Moreover, it was demonstrated that the methodological approach used for estimation of EFs and the definition of spatial boundaries could influence the obtained results.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Average emission factors, Climate change, Life Cycle Assessment, Marginal emission factors, Solar microgrid
National Category
Environmental Engineering
Identifiers
urn:nbn:se:kth:diva-276342 (URN)10.1016/j.apenergy.2020.114981 (DOI)000537357800021 ()2-s2.0-85083367565 (Scopus ID)
Note

QC 20200616

Available from: 2020-06-16 Created: 2020-06-16 Last updated: 2022-06-26Bibliographically approved
Nilsson, J., Sundberg, C., Tidaker, P. & Hansson, P.-A. (2020). Regional variation in climate impact of grass-based biogas production: A Swedish case study. Journal of Cleaner Production, 275, Article ID 122778.
Open this publication in new window or tab >>Regional variation in climate impact of grass-based biogas production: A Swedish case study
2020 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 275, article id 122778Article in journal (Refereed) Published
Abstract [en]

Transitioning from a fossil economy to a bio-economy will inevitably increase the demand for biomass production. One strategy to meet the demand is to re-cultivate set-aside arable land. This study investigated the climate impact and energy potential of grass-based biogas produced using fallow land in Uppsala municipality, Sweden. The assessment was performed on regional level for more than 1000 individual sites, using the agro-ecosystem model DeNitrification DeComposition (DNDC) in combination with time-dynamic life cycle assessment methodology. The results showed that the system could significantly increase biogas production within the region, which would reduce the climate impact by 9950 Mg CO2-eq per year. Compared with diesel fuel, the grass-based biogas gave a GWP reduction of 85%. However, the site-specific GWP reduction showed large spatial variability, ranging between 102 and 79% compared with diesel fuel, depending on where in the region the grass was cultivated. Two alternative scenarios were investigated, increased mineral N fertilisation and inclusion of N-fixing crops in the feedstock mixture. The highest mitigation per biogas energy produced was found for the N-fixing scenario but, because of lower yields, this scenario had lower total mitigation potential for the region than the increased fertilisation scenario. The increased fertilisation scenario had a lower climate mitigation effect per biogas energy produced, but the highest mitigation potential when the whole region was considered, because of the increased biogas production. The method applied in this study can guide land-use planning of local energy production from arable land, also for other regions.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Grass cultivation, Biomethane, Soil carbon sequestration, DNDC, Regional-LCA, Soil N2O emissions
National Category
Renewable Bioenergy Research
Identifiers
urn:nbn:se:kth:diva-286639 (URN)10.1016/j.jclepro.2020.122778 (DOI)000579495100030 ()2-s2.0-85088627503 (Scopus ID)
Note

QC 20201127

Available from: 2020-11-27 Created: 2020-11-27 Last updated: 2022-06-25Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5979-9521

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