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Temporal climate impacts of using willow and logging residues for district heating in Sweden

Hammar, Torun (2015). Temporal climate impacts of using willow and logging residues for district heating in Sweden. Uppsala : Sveriges lantbruksuniv. , Rapport / Institutionen för energi och teknik, SLU, 1654-9406 ; 084
ISBN 978-91-576-9296-2
eISBN 978-91-576-9297-9
[Licentiate thesis]

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Abstract

Using bioenergy to replace fossil fuels has been adopted as a climate mitigation measure, since less greenhouse gases are expected to be released into the atmosphere. In Sweden, the share of bioenergy is relative high (about 23% of total consumption including peat), with a relatively large proportion originating from domestically produced forest biomass.

This thesis examined the climate impact of using two types of woody biomass (willow, logging residues) for district heating, using time-dependent life cycle assessment methodology. The climate impact of the wood-based energy systems was determined and compared with that of the fossil fuels coal and natural gas. The focus was on the temporal dynamics of carbon fluxes between soil, biomass and atmosphere.

Establishing willow on agricultural land provided the potential to sequester carbon from atmosphere to soil, giving a net cooling effect on global mean temperature. However, this effect was shown to be highly dependent on willow yield (i.e. productivity), with low yield potentially decreasing soil carbon content. Moreover, district heating from willow chips gave a lower warming effect than coal and natural gas, irrespective of yield.

Combustion of forest biomass in the form of logging residues also gave a lower warming effect than coal and natural gas. However, the climate benefits compared with natural gas were delayed by 15-20 years (depending on geographical location) due to the chemical composition of natural gas, which generates less greenhouse gas emissions than coal and logging residues during extraction and combustion. Nevertheless, when decomposition of unharvested forest biomass was included in the reference systems, bioenergy from logging residues had climate benefits compared with coal and natural gas.

Authors/Creators:Hammar, Torun
Title:Temporal climate impacts of using willow and logging residues for district heating in Sweden
Series/Journal:Rapport / Institutionen för energi och teknik, SLU (1654-9406)
Year of publishing :2015
Depositing date:30 March 2015
Volume:084
Number of Pages:59
Papers/manuscripts:
NumberReferences
IHammar, T., Ericsson, N., Sundberg, C. & Hansson, P.-A. (2014). Climate impact of willow grown for bioenergy in Sweden. BioEnergy Research 7(4), 1529-1540. doi:10.1007/s12155-014-9490-0.
IIHammar, T., Ortiz, C., Stendahl, J., Ahlgren, S. & Hansson P.-A. (2015). Time-dynamic effects on global temperature when harvesting logging residues for bioenergy. Submitted.
Place of Publication:Uppsala
Publisher:Institutionen för energi och teknik, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-9296-2
ISBN for electronic version:978-91-576-9297-9
ISSN:1654-9406
Language:English
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
P Natural resources > P06 Renewable energy resources
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Climate Research
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 207 Environmental Engineering > Energy Systems
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Renewable Bioenergy Research
Agrovoc terms:salix, logging wastes, bioenergy, climatic change, temperature, greenhouse gases, carbon cycle, soil organic matter, wood chips, short rotation forestry, sweden
Keywords:Temperature change, global warming, greenhouse gas (GHG), soil organic carbon (SOC), biogenic carbon, life cycle assessment (LCA), bioenergy, forest biomass, wood chips, short-rotation forestry
URN:NBN:urn:nbn:se:slu:epsilon-e-2529
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2529
ID Code:12051
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Energy and Technology
External funders:Energimyndigheten and FORMAS
Deposited By: Torun Hammar
Deposited On:31 Mar 2015 07:27
Metadata Last Modified:08 Sep 2017 09:20

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