Time-Dynamic Effects on the Global Temperature When Harvesting Logging Residues for Bioenergy

Abstract

The climate mitigation potential of using logging residues (tree tops and branches) for bioenergy has been debated. In this study, a time-dependent life cycle assessment (LCA) was performed using a single-stand perspective. Three forest stands located in different Swedish climate zones were studied in order to assess the global temperature change when using logging residues for producing district heating. These systems were compared with two fossil reference systems in which the logging residues were assumed to remain in the forest to decompose over time, while coal or natural gas was used for energy. The results showed that replacing coal with logging residues gave a direct climate benefit from a single-stand perspective, while replacing natural gas gave a delayed climate benefit of around 8-12 years depending on climate zone. A sensitivity analysis showed that the time was strongly dependent on the assumptions for extraction and combustion of natural gas. The LCA showed that from a single-stand perspective, harvesting logging residues for bioenergy in the south of Sweden would give the highest temperature change mitigation potential per energy unit. However, the differences between the three climate zones studied per energy unit were relatively small. On a hectare basis, the southern forest stand would generate more biomass compared to the central and northern locations, which thereby could replace more fossil fuel and give larger climate benefits.

Biomass Residues to Renewable Energy: A Life Cycle Perspective Applied at a Local Scale

“…A similar topic has been discussed, regarding the wood residues in British Columbia (Canada) [27]: for small scale community cogenerating plant the use of wood residues generated the As depicted, the use of wood residues leads to considerable benefits in terms of climate change (considering a 100-years perspective) and of fossil fuels depletion, −41% and −40%, respectively. Similar GHGs mitigation trend was already outlined by previous works [7,8], which suggested the importance of using wood-based appliances to reduce climate change effects. Furthermore, Paredes-Sánchez et al [26] studied the valorization of residues in Asturias, Spain, where the use of biomass offers the opportunity to create a new path to economic development with a reduction of Energies 2016, 9, 922 10 of 15 CO 2 emissions.…”

“…The general framework (Figure 2), defined by the ISO 14040 and 14044 [12,13], consists of four conceptual phases, namely: Goal and Scope definition, Life Cycle Inventory (LCI), Life Cycle Impact Assessment (LCIA) and Interpretation. LCA is an extremely versatile methodology, useful to investigate different sectors, such as the renewable energy from biomass [6][7][8][9][10], the bio-based industry [14,15], the chemical and pharmaceutical sectors [16,17] and the waste management systems [18]. The simulation was carried out using SimaPro software (version 8.0.…”

“…Wolf et al [7] focused the attention on the Bavarian situation, stressing that it is necessary to focus on regional aspects when assessing the environmental impacts of heat provision. The use of different logging residues to produce bioenergy was also investigated by Hammar et al [8], taking into account Swedish conditions. Another work outlines the importance of an integrative resources management aimed to close the loop of the production systems, to implement a suitable strategy in line with the regulatory framework [9].…”

Stump harvesting for bioenergy: A review of climatic and environmental impacts in northern Europe and America

“…By using ecosystem models (Heureka and Q models) that describe the development of the forest carbon pools combined with LCA methodology, Hammar, Ortiz, Stendahl, Ahlgren, and Hansson () and Ortiz et al () estimated the climate impact (temperature increase) for the energy systems based on stumps of Norway spruce for three regions in Sweden. According to this analysis, the climate impact of stump energy from a single harvest reached a maximum after 10–15 years but then declined sharply (Figure , “Climate impact of a single harvest of stumps”).…”

Time‐dependent climate impact and energy efficiency of combined heat and power production from short‐rotation coppice willow using pyrolysis or direct combustion

“…A few studies have used DT S as an indicator for the time-dependent climate impacts of bioenergy systems (e.g. Cherubini et al, 2013;Ericsson et al, 2013Hammar et al, 2014Hammar et al, , 2015Giuntoli et al, 2015;Ortiz et al, 2016;Pors€ o et al, 2016), but to our knowledge, no such study has been presented on pyrolysis-based bioenergy systems. However, several authors have investigated the climate impact and energy efficiency of pyrolysis-based bioenergy systems from a life cycle perspective based on GWP (Gaunt and Lehmann, 2008;Roberts et al, 2010;Hammond et al, 2011;Hanandeh, 2012;Ibarrola et al, 2012;Wang et al, 2013;Peters et al, 2015;Thornley et al, 2015).…”