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Carvalho, Ricardo L.
Alternative names
Publications (5 of 5) Show all publications
Kristensen, T. B., Falk, J., Lindgren, R., Andersen, C., Malmborg, V. B., Eriksson, A. C., . . . Svenningsson, B. (2021). Properties and emission factors of cloud condensation nuclei from biomass cookstoves - Observations of a strong dependency on potassium content in the fuel. Atmospheric Chemistry And Physics, 21(10), 8023-8044
Open this publication in new window or tab >>Properties and emission factors of cloud condensation nuclei from biomass cookstoves - Observations of a strong dependency on potassium content in the fuel
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2021 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 21, no 10, p. 8023-8044Article in journal (Refereed) Published
Abstract [en]

Residential biomass combustion is a significant source of aerosol particles on regional and global scales influencing climate and human health. The main objective of the current study was to investigate the properties of cloud condensation nuclei (CCN) emitted from biomass burning of solid fuels in different cookstoves mostly of relevance to sub- Saharan east Africa.

The traditional three-stone fire and a rocket stove were used for combustion of wood logs of Sesbania and Casuarina with birch used as a reference. A natural draft and a forced-draft pellet stove were used for combustion of pelletised Sesbania and pelletised Swedish softwood alone or in mixtures with pelletised coffee husk, rice husk or water hyacinth. The CCN activity and the effective density were measured for particles with mobility diameters of v65, v100 and v200 nm, respectively, and occasionally for 350 nm particles. Particle number size distributions were measured online with a fast particle analyser. The chemical composition of the fuel ash was measured by application of standard protocols.

The average particle number size distributions were by number typically dominated by an ultrafine mode, and in most cases a soot mode was centred around a mobility diameter of v150 nm. The CCN activities decreased with increasing particle size for all experiments and ranged in terms of the hygroscopicity parameter, from v0:1 to v0:8 for the ultrafine mode and from v0:001 to v0:15 for the soot mode. The CCN activity of the ultrafine mode increased (i) with increasing combustion temperature for a given fuel, and (ii) it typically increased with increasing potassium concentration in the investigated fuels. The primary CCN and the estimated particulate matter (PM) emission factors were typically found to increase significantly with increasing potassium concentration in the fuel for a given stove. In order to link CCN emission factors to PM emission factors, knowledge about stove technology, stove operation and the inorganic fuel ash composition is needed. This complicates the use of ambient PM levels alone for estimation of CCN concentrations in regions dominated by biomass combustion aerosol, with the relation turning even more complex when accounting for atmospheric ageing of the aerosol.

Place, publisher, year, edition, pages
Nicolaus Copernicus University Press, 2021
National Category
Meteorology and Atmospheric Sciences Subatomic Physics
Identifiers
urn:nbn:se:umu:diva-184206 (URN)10.5194/acp-21-8023-2021 (DOI)000657139000001 ()2-s2.0-85106885614 (Scopus ID)
Funder
Swedish Research Council, 2017-05016Swedish Research Council, 2018- 04200Swedish Research Council Formas, 2015-992Swedish Research Council Formas, 2015-1385Swedish Research Council FormasThe Kempe Foundations, JCK-1516Bio4Energy
Available from: 2021-06-14 Created: 2021-06-14 Last updated: 2023-09-05Bibliographically approved
Carvalho, R. L., Yadav, P., García-López, N., Lindgren, R., Nyberg, G., Diaz-Chavez, R., . . . Athanassiadis, D. (2020). Environmental Sustainability of Bioenergy Strategies in Western Kenya to Address Household Air Pollution. Energies, 13(3), Article ID 719.
Open this publication in new window or tab >>Environmental Sustainability of Bioenergy Strategies in Western Kenya to Address Household Air Pollution
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2020 (English)In: Energies, E-ISSN 1996-1073, Vol. 13, no 3, article id 719Article in journal (Refereed) Published
Abstract [en]

Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden of disease due to household air pollution. Efficient biomass cooking is a local-based renewable energy solution to address this issue. The Life-Cycle Assessment tool Simapro 8.5 is applied for analyzing the environmental impact of four biomass cooking strategies for the Kisumu County, with analysis based on a previous energy modelling study, and literature and background data from the Ecoinvent and Agrifootprint databases applied to the region. A Business-As-Usual scenario (BAU) considers the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) consider the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluates a mix of the ICS, PGS and BGS. In the BGS, the available biomass waste is sufficient to be upcycled and fulfill cooking demands by 2035. This scenario has the lowest impact on all impact categories analyzed followed by the PGS and INT. Further work should address a detailed socio-economic analysis of the analyzed scenarios.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
agroforestry, waste valorization, sustainable development goals, renewable energy, bioenergy transitions, circular bioeconomy, clean cooking, life-cycle assessment, energy policy
National Category
Bioenergy
Identifiers
urn:nbn:se:umu:diva-170012 (URN)10.3390/en13030719 (DOI)000522489000212 ()2-s2.0-85079543499 (Scopus ID)
Projects
Bio4Energy
Funder
Bio4Energy
Available from: 2020-05-05 Created: 2020-05-05 Last updated: 2023-08-28Bibliographically approved
Korhonen, K., Kristensen, T. B., Falk, J., Lindgren, R., Andersen, C., Carvalho, R. L., . . . Virtanen, A. (2020). Ice-nucleating ability of particulate emissions from solid-biomass-fired cookstoves: an experimental study. Atmospheric Chemistry And Physics, 20(8), 4951-4968
Open this publication in new window or tab >>Ice-nucleating ability of particulate emissions from solid-biomass-fired cookstoves: an experimental study
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2020 (English)In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 20, no 8, p. 4951-4968Article in journal (Refereed) Published
Abstract [en]

This research was part of the Salutary Umea Study of Aerosols in Biomass Cookstove Emissions (SUSTAINE) laboratory experiment campaign. We studied ice-nucleating abilities of particulate emissions from solid-fuel-burning cookstoves, using a portable ice nuclei counter, Spectrometer Ice Nuclei (SPIN). These emissions were generated from two traditional cookstove types commonly used for household cooking in sub-Saharan Africa and two advanced gasifier stoves under research to promote sustainable development alternatives. The solid fuels studied included biomass from two different African tree species, Swedish softwood and agricultural residue products relevant to the region. Measurements were performed with a modified version of the standard water boiling test on polydisperse samples from flue gas during burning and size-selected accumulation mode soot particles from a 15 m(3) aerosol-storage chamber. The studied soot particle sizes in nanometers were 250, 260, 300, 350, 400, 450 and 500. From this chamber, the particles were introduced to water-supersaturated freezing conditions (-32 to -43 degrees) in the SPIN. Accumulation mode soot particles generally produced an ice-activated fraction of 10 3 in temperatures 1-1.5 degrees C higher than that required for homogeneous freezing at fixed RHw = 115 %. In five special experiments, the combustion performance of one cookstove was intentionally modified. Two of these exhibited a significant increase in the ice-nucleating ability of the particles, resulting in a 10(3) ice activation at temperatures up to 5.9 degrees C higher than homogeneous freezing and the observed increased ice-nucleating ability. We investigated six different physico-chemical properties of the emission particles but found no clear correlation between them and increasing ice-nucleating ability. We conclude that the freshly emitted combustion aerosols form ice via immersion and condensation freezing at temperatures only moderately above homogeneous freezing conditions.

Place, publisher, year, edition, pages
Nicolaus Copernicus University Press, 2020
National Category
Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:umu:diva-170825 (URN)10.5194/acp-20-4951-2020 (DOI)000529394700004 ()2-s2.0-85084222985 (Scopus ID)
Projects
Bio4Energy
Funder
Swedish Research Council Formas, 942-2015-1385Swedish Research Council Formas, 2015-992Swedish Research Council Formas, 2013-01023Swedish Research Council, 2017-05016Swedish Research Council, 2018-04200Swedish Research Council, 2013-05021The Kempe Foundations, JCK-1516Bio4Energy
Available from: 2020-05-25 Created: 2020-05-25 Last updated: 2023-03-24Bibliographically approved
Carvalho, R. L., Yadav, P., Lindgren, R., García-López, N., Nyberg, G., Diaz-Chavez, R., . . . Athanassiadis, D. (2019). Bioenergy strategies to address deforestation and household air pollution in western Kenya. In: European Biomass Conference and Exhibition Proceedings: . Paper presented at 27th European Biomass Conference and Exhibition, EUBCE 2019, Lisbon, Portugal, May 27-30, 2019 (pp. 1536-1542). ETA-Florence Renewable Energies
Open this publication in new window or tab >>Bioenergy strategies to address deforestation and household air pollution in western Kenya
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2019 (English)In: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, p. 1536-1542Conference paper, Published paper (Refereed)
Abstract [en]

Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden disease due to household air pollution. The Long-Range Energy Alternatives Planning (LEAP) system and the Life-Cycle Assessment tool Simapro 8.5 were applied for analyzing biomass strategies for the region. The calculation of the residential energy consumption and emissions was based on scientific reviews and original data from experimental studies. The research shows the effect of four biomass strategies on the reduction of wood fuel use and short-lived climate pollutant emissions. A Business As Usual scenario (BAU) considered the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) considered the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluated a mix of the ICS, PGS and BGS. The study shows that, energy use will increase by 8% (BGS), 20% (INT), 26% (PGS), 42% (ICS) and 56% (BAU). The BGS has the lowest impact on global warming, particle formation, terrestrial acidification, fossil resource scarcity, water consumption, as well as on eutrophication followed by the PGS and INT.

Place, publisher, year, edition, pages
ETA-Florence Renewable Energies, 2019
Series
European biomass conference and exhibition proceedings, E-ISSN 2282-5819
Keywords
Agroforestry, Bioenergy transitions, Clean cooking, Energy policy, Life-cycle assessment, Solid-biofuels
National Category
Bioenergy Energy Systems
Identifiers
urn:nbn:se:umu:diva-203424 (URN)2-s2.0-85071068129 (Scopus ID)
Conference
27th European Biomass Conference and Exhibition, EUBCE 2019, Lisbon, Portugal, May 27-30, 2019
Available from: 2023-01-18 Created: 2023-01-18 Last updated: 2023-03-24Bibliographically approved
Carvalho, R. L., Lindgren, R., Lopez, N., Nyambane, A., Nyberg, G., Diaz-Chavez, R. & Boman, C. (2019). Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya. Energy Policy, 131, 168-186
Open this publication in new window or tab >>Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya
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2019 (English)In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 131, p. 168-186Article in journal (Refereed) Published
Abstract [en]

Traditional cooking is today's largest global environmental health risk. Over 640 million people in Africa are expected to rely on biomass for cooking by 2040. In Kenya, cooking inefficiently with wood and charcoal persists as a cause of deforestation and household air pollution. This research analyses the effects of four biomass cookstove strategies on reducing air pollutant emissions in Kisumu County between 2015 and 2035 using the Long-Range Energy Alternatives Planning system. The Business as Usual scenario (BAU) was developed considering the historical trends in household energy use. Energy transition scenarios to Improved Cookstoves (ICS), Pellet Gasifier Stoves (PGS) and Biogas Stoves (BGS) were applied to examine the impact of these systems on energy savings and air pollution mitigation. An integrated scenario (INT) was evaluated as a mix of the ICS, PGS and BGS. The highest energy savings, in relation to the BAU, are achieved in the BGS (30.9%), followed by the INT (23.5%), PGS (19.4%) and ICS (9.2%). The BGS offers the highest reduction in the GHG (37.6%), CH4 (94.3%), NMVOCs (85.0%), CO (97.4%), PM2.5 (64.7%) and BC (48.4%) emissions, and the PGS the highest reduction in the N2O (83.0%) and NOx (90.7%) emissions, in relation to the BAU.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Biomass pellets, Biogas, Cookstoves, Energy forecasting, Global warming, Local air pollutants
National Category
Energy Systems Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-161498 (URN)10.1016/j.enpol.2019.04.026 (DOI)000472125200015 ()2-s2.0-85065396669 (Scopus ID)
Projects
Bio4Energy
Funder
Swedish Research Council Formas, 942-2015-1385The Kempe Foundations, JCK-1516Bio4Energy
Available from: 2019-07-12 Created: 2019-07-12 Last updated: 2023-03-24Bibliographically approved
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