14 research outputs found
Land-Use and Climate Effects of Bioenergy: Carbon balances of Swedish forest bioenergy systems â and â Geospatial biomass supply-and-demand matching for Europe
In order to keep global warming below 2 degrees Celsius, greenhouse gas emissions have to be drastically reduced. Bioenergy can play a role in climate change mitigation by substituting for energy from fossil fuels; however, biomass is a limited resource associated with emissions from land use and land-use change. Climate benefits of using biomass for energy have been called into question, with studies reaching conflicting conclusions. These conflicts can in part be explained by differences in methodological approaches and critical parameters, as well as by differences among the assessed bioenergy systems, e.g., the geographic location and associated land use. This thesis combines five papers to provide a better understanding of the interactions between biomass supply and demand and the implications for land use and for climate change and other environmental impacts. Papers I and II bring together different methodological perspectives to analyze the effects on land use, biomass production, and forest carbon balances of using forest bioenergy. The papers show how the climate benefits of forest bioenergy systems can depend on the scale of the assessment, structure of the forests studied, market prospects for bioenergy and other forest products, and energy system developments. Paper III analyzes the role of the Swedish forest sector in future energy scenarios and in reaching the 2050 goal of climate neutrality. The paper finds that the Swedish forest can make an important contribution by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The results are placed in the context of the 2-degree target by allocating a CO2 emissions budget to Sweden. Paper IV presents a geographical information system modeling framework (1,000 m resolution) for assessing and analyzing the availability and cost of forest and agricultural residues in relation to localized biomass demand for co-firing with coal. The paper shows that using agricultural residues reduces transport distances and thereby transport costs. Paper V extends the modeling framework used in Paper IV to include energy crops in assessing biomass availability and costs in the context of bio-electricity and bio-refineries, and considers potential environmental consequences associated with energy crops. The paper shows that lignocellulosic crops can complement residues and help mitigate a selected number of environmental impacts on agricultural land
Geospatial supply-demand modeling of lignocellulosic biomass for electricity and biofuels in the European Union
Bioenergy can contribute to achieving European Union (EU) climate targets while mitigating impacts from current agricultural land use. A GIS-based modeling framework (1000 m resolution) is employed to match biomass supply (forest and agricultural residues, complemented by lignocellulosic energy crops where needed) with biomass demand for either electricity or bio-oil production on sites currently used for coal power in the EU-28, Norway, and Switzerland. The framework matches supply and demand based on minimizing the field-to-gate costs and is used to provide geographically explicit information on (i) plant-gate supply cost; (ii) CO2 savings; and (iii) potential mitigation opportunities for soil erosion, flooding, and eutrophication resulting from the introduction of energy crops on cropland. Converting all suitable coal power plants to biomass and assuming that biomass is sourced within a transport distance of 300 km, would produce an estimated 150 TW h biomass-derived electricity, using 1365 PJ biomass, including biomass from energy crops grown on 6 Mha. Using all existing coal power sites for bio-oil production in 100-MW pyrolysis units could produce 820 PJ of bio-oil, using 1260 PJ biomass, including biomass from energy crops grown on 1.8 Mha. Using biomass to generate electricity would correspond to an emissions reduction of 135 MtCO2, while using biomass to produce bio-oil to substitute for crude oil would correspond to a reduction of 59 MtCO2. In addition, energy crops can have a positive effect on soil organic carbon in most of the analyzed countries. The mitigation opportunities investigated range from marginal to high depending on location
Sustainable biofuels - critical review of current views and case studies using extended systems analysis providing new perspectives and positive examples.
On the contribution of forest bioenergy to climate change mitigation
Greenhouse gas (GHG) emissions have to be drastically reduced to keep global warming below 2 degrees. Bioenergy can play a role in climate change mitigation by substituting for fossil fuels. However, climate benefits associated with forest-based bioenergy are being questioned, and studies arrive at contrasting conclusions, mainly due to diverging methodological choices and assumptions. This thesis combines three papers to bring together different methodological perspectives to improve the assessment and understanding of the contribution of forest bioenergy to climate change mitigation. The thesis concerns carbon balances and GHG-mediated climate effects associated with the use of forest biomass for energy in Sweden. More specifically, the focus is on methodological choices including definition of spatial and temporal system boundaries, and character of forests and forest product markets, e.g., forest ownersâ responses to changes in demand for forest products, and how different assessment scales and metrics capture the difference in timing between emission and sequestration of carbon in forests that are managed with long rotations.The results show that the assessed climate benefits of promoting forest bioenergy systems can differ depending on the scale of the assessment, the forest structure, market prospects for bioenergy and other forest products, and energy system developments. Based on these findings, we recommend that assessments intending to support policy-making (i) consider how an increase in bioenergy demand affects the forest carbon stock at the landscape level, i.e., the scale at which forest operations are typically coordinated; (ii) be context-specific rather than feedstock-specific; (iii) consider changes in forest management driven by increased bioenergy demand, which can affect forest carbon stock and climate change mitigation; (iv) combine the assessment with energy system modeling to understand the size and development of bioenergy demand and different technology pathways; and (v) acknowledge short-term vs. long-term benefits, as some bioenergy systems could be associated with initial forest stock losses but great long-term benefits that can be overlooked if the temporal scope is too narrow. The latter is especially relevant when the ultimate goal is a long-term climate target, e.g.., the 2-degree target.This thesis also shows that the Swedish forest sector can make an important contribution to the 2045 goal of climate neutrality, i.e., no net GHG emissions to the atmosphere, by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The results indicate that the neutrality target can only be reached by 2050 if the net carbon balance effect from the forest is considered. Additionally, measures to enhance forest productivity can increase the output of forest products (including bioenergy) and also enhance carbon sequestration in forests and products, reaching net negative emissions earlier. All in all, studies intending to support policy- and decision-making may provide more relevant information if the focus is shifted from assessing individual bioenergy systems to consider all forest products and how forest management planning as a whole is affected by bioenergy incentives - and how this in turn affects carbon balances in forest landscapes and forest product pools. Studies should preferably employ several alternative scenarios for critical factors, including policy options, forest product markets, and energy technology pathways
On the contribution of forest bioenergy to climate change mitigation
Greenhouse gas (GHG) emissions have to be drastically reduced to keep global warming below 2 degrees. Bioenergy can play a role in climate change mitigation by substituting for fossil fuels. However, climate benefits associated with forest-based bioenergy are being questioned, and studies arrive at contrasting conclusions, mainly due to diverging methodological choices and assumptions. This thesis combines three papers to bring together different methodological perspectives to improve the assessment and understanding of the contribution of forest bioenergy to climate change mitigation. The thesis concerns carbon balances and GHG-mediated climate effects associated with the use of forest biomass for energy in Sweden. More specifically, the focus is on methodological choices including definition of spatial and temporal system boundaries, and character of forests and forest product markets, e.g., forest ownersâ responses to changes in demand for forest products, and how different assessment scales and metrics capture the difference in timing between emission and sequestration of carbon in forests that are managed with long rotations.The results show that the assessed climate benefits of promoting forest bioenergy systems can differ depending on the scale of the assessment, the forest structure, market prospects for bioenergy and other forest products, and energy system developments. Based on these findings, we recommend that assessments intending to support policy-making (i) consider how an increase in bioenergy demand affects the forest carbon stock at the landscape level, i.e., the scale at which forest operations are typically coordinated; (ii) be context-specific rather than feedstock-specific; (iii) consider changes in forest management driven by increased bioenergy demand, which can affect forest carbon stock and climate change mitigation; (iv) combine the assessment with energy system modeling to understand the size and development of bioenergy demand and different technology pathways; and (v) acknowledge short-term vs. long-term benefits, as some bioenergy systems could be associated with initial forest stock losses but great long-term benefits that can be overlooked if the temporal scope is too narrow. The latter is especially relevant when the ultimate goal is a long-term climate target, e.g.., the 2-degree target.This thesis also shows that the Swedish forest sector can make an important contribution to the 2045 goal of climate neutrality, i.e., no net GHG emissions to the atmosphere, by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The results indicate that the neutrality target can only be reached by 2050 if the net carbon balance effect from the forest is considered. Additionally, measures to enhance forest productivity can increase the output of forest products (including bioenergy) and also enhance carbon sequestration in forests and products, reaching net negative emissions earlier. All in all, studies intending to support policy- and decision-making may provide more relevant information if the focus is shifted from assessing individual bioenergy systems to consider all forest products and how forest management planning as a whole is affected by bioenergy incentives - and how this in turn affects carbon balances in forest landscapes and forest product pools. Studies should preferably employ several alternative scenarios for critical factors, including policy options, forest product markets, and energy technology pathways
SUSTAINABILITY (AND GHG) ASSESSMENT OF FOREST-BASED AVIATION BIOFUEL IN SWEDEN
The overall aim of the project, Forestry to jet (F2J), is to produce sustainable aviaion fuel (SAF)from residual forest biomass to meet Swedaviaâs target of a fossil free national aviation sector in 2030. Task 2.1 concluded that industrial forest residues (e.g., sawdust, bark, shavings) and harvest residues (i.e., top, brunches, and stumps) can be used as possible feedstock for a continuous production of SAF with Alcohol-to Jet and Sugar-to Jet processes in Sweden. In this context, the objective of this task is to identify potential sustainability issues regarding the selected feedstock as well as to perform a well-to-wing greenhouse gas (GHG) assessment of selected supply chain. The sustainability of bio-jets is strongly dependent on the availability of sustainable feedstock. The availability of forest-based residues for SAF depends on the development of the Swedish forest and forest industry (for instance, demand for timber and pulp and paper) and on the sustainability constraints for residue removals. Swedish forestry is an important source of sustainable material supply. The forest is managed according to the Forestry Act, which gives equal importance to production and environmental goals to obtain a long-term sustainable flow of forest products while preserving ecological processes and biodiversity. The harvested timber is mainly used in saw- and pulp-mills. Residues from saw-mills constitute a potential source of feedstock (2.7 million tons DS) but are used to a large extent. Residues from harvested biomass (tops, branches and stumps) represent an additional source of feedstock for SAF; however, their extraction could lead to environmental challenges such as a reduction in soil and water quality and biodiversity. Currently, about 2.2 million tons DS of harvest residues are used for energy and studies have shown that harvest levels can be further increased to obtain additional 3.3 million tons DS while still being considering sustainable. In this way, the available feedstock would correspond to 1.5 times the total need for the aviation fuel in Sweden (2.3 million tons DS). Sustainable feedstock is determined according to certain âsafe thresholdsâ for harvest residues. The reviewed studies estimated these thresholds so that the extraction of residues does not contribute to forest production reduction, biodiversity loss, acidification, eutrophication, and toxic substances. For a more comprehensive sustainability assessment, other aspects of sustainability, including socio-economic aspects should be considered. It is also relevant to investigate how the demand for SAF affects the availability of feedstock for other competing uses.Forestry to jet (F2J) is a project financed by the Swedishnational transport administration. The project consortiumconsist of COWI (project leader), RISE (project owner), FlyGreen Fund, SEKAB, SkyNRG and Swedavia.</p
SUSTAINABILITY (AND GHG) ASSESSMENT OF FOREST-BASED AVIATION BIOFUEL IN SWEDEN
The overall aim of the project, Forestry to jet (F2J), is to produce sustainable aviaion fuel (SAF)from residual forest biomass to meet Swedaviaâs target of a fossil free national aviation sector in 2030. Task 2.1 concluded that industrial forest residues (e.g., sawdust, bark, shavings) and harvest residues (i.e., top, brunches, and stumps) can be used as possible feedstock for a continuous production of SAF with Alcohol-to Jet and Sugar-to Jet processes in Sweden. In this context, the objective of this task is to identify potential sustainability issues regarding the selected feedstock as well as to perform a well-to-wing greenhouse gas (GHG) assessment of selected supply chain. The sustainability of bio-jets is strongly dependent on the availability of sustainable feedstock. The availability of forest-based residues for SAF depends on the development of the Swedish forest and forest industry (for instance, demand for timber and pulp and paper) and on the sustainability constraints for residue removals. Swedish forestry is an important source of sustainable material supply. The forest is managed according to the Forestry Act, which gives equal importance to production and environmental goals to obtain a long-term sustainable flow of forest products while preserving ecological processes and biodiversity. The harvested timber is mainly used in saw- and pulp-mills. Residues from saw-mills constitute a potential source of feedstock (2.7 million tons DS) but are used to a large extent. Residues from harvested biomass (tops, branches and stumps) represent an additional source of feedstock for SAF; however, their extraction could lead to environmental challenges such as a reduction in soil and water quality and biodiversity. Currently, about 2.2 million tons DS of harvest residues are used for energy and studies have shown that harvest levels can be further increased to obtain additional 3.3 million tons DS while still being considering sustainable. In this way, the available feedstock would correspond to 1.5 times the total need for the aviation fuel in Sweden (2.3 million tons DS). Sustainable feedstock is determined according to certain âsafe thresholdsâ for harvest residues. The reviewed studies estimated these thresholds so that the extraction of residues does not contribute to forest production reduction, biodiversity loss, acidification, eutrophication, and toxic substances. For a more comprehensive sustainability assessment, other aspects of sustainability, including socio-economic aspects should be considered. It is also relevant to investigate how the demand for SAF affects the availability of feedstock for other competing uses.Forestry to jet (F2J) is a project financed by the Swedishnational transport administration. The project consortiumconsist of COWI (project leader), RISE (project owner), FlyGreen Fund, SEKAB, SkyNRG and Swedavia.</p
Biodrivmedel och styrmedel i EU
Inblandning av biodrivmedel Ă€r en viktig faktor för att Sverige ska klara mĂ„let om 70 % utslĂ€ppsminskningar i transportsektorn till 2030. Sverige Ă€r redan idag en av de största konsumenterna av biodrivmedel för transporter i EU, och 85% av de biodrivmedel som anvĂ€nds kommer frĂ„n import. Sverige pĂ„verkas direkt av EU-lagstiftning för biodrivmedel, men eftersom biodrivmedel handlas internationellt pĂ„verkas vĂ„r möjlighet att importera och exportera biodrivmedel Ă€ven av tillgĂ„ng och efterfrĂ„gan i andra lĂ€nder. För att kunna utforma effektiva svenska styrmedel Ă€r det dĂ€rför viktigt att förstĂ„ hur produktion, konsumtion och styrmedel för biodrivmedel ser ut i andra lĂ€nder i EU. Precis som i Sverige sĂ„ drivs konsumtion av biodrivmedel i andra EU-lĂ€nder framför allt av styrmedel som pĂ„verkar konsumtion. Det vanligaste styrmedlet Ă€r inblandningskvoter liknande den svenska reduktionsplikten. I det nya förnybartdirektivet frĂ„n EU (RED II) som kom 2018 lĂ€ggs ett större fokus pĂ„ avancerade biodrivmedel och mĂ„let Ă€r att de ska utgöra minst 0,2 % 2022, 1 % 2025 och 3,5 % 2030. 2020 hade 20 EU-lĂ€nder (inklusive Storbritannien) egna nationella kvoter med krav pĂ„ inblandning av avancerade biodrivmedel. Sverige har Ă€n sĂ„ lĂ€nge inte en speciell kvot för avancerade biodrivmedel. Det finns dock ett flertal planerade anlĂ€ggningar i Sverige som kan komma att bli stora producenter av avancerade biodrivmedel. TillgĂ€nglig pĂ„ https://f3centre.se/sv/samverkansprogram/  En delrapport frĂ„n ett projekt inom FĂRNYBARA DRIVMEDEL OCH SYSTEM 2018-2021. Ett samverkansprogram mellan Energimyndigheten och f3 Svenskt kunskapscentrum för förnybara drivmedel.</p
Biodrivmedel och styrmedel i EU
Inblandning av biodrivmedel Ă€r en viktig faktor för att Sverige ska klara mĂ„let om 70 % utslĂ€ppsminskningar i transportsektorn till 2030. Sverige Ă€r redan idag en av de största konsumenterna av biodrivmedel för transporter i EU, och 85% av de biodrivmedel som anvĂ€nds kommer frĂ„n import. Sverige pĂ„verkas direkt av EU-lagstiftning för biodrivmedel, men eftersom biodrivmedel handlas internationellt pĂ„verkas vĂ„r möjlighet att importera och exportera biodrivmedel Ă€ven av tillgĂ„ng och efterfrĂ„gan i andra lĂ€nder. För att kunna utforma effektiva svenska styrmedel Ă€r det dĂ€rför viktigt att förstĂ„ hur produktion, konsumtion och styrmedel för biodrivmedel ser ut i andra lĂ€nder i EU. Precis som i Sverige sĂ„ drivs konsumtion av biodrivmedel i andra EU-lĂ€nder framför allt av styrmedel som pĂ„verkar konsumtion. Det vanligaste styrmedlet Ă€r inblandningskvoter liknande den svenska reduktionsplikten. I det nya förnybartdirektivet frĂ„n EU (RED II) som kom 2018 lĂ€ggs ett större fokus pĂ„ avancerade biodrivmedel och mĂ„let Ă€r att de ska utgöra minst 0,2 % 2022, 1 % 2025 och 3,5 % 2030. 2020 hade 20 EU-lĂ€nder (inklusive Storbritannien) egna nationella kvoter med krav pĂ„ inblandning av avancerade biodrivmedel. Sverige har Ă€n sĂ„ lĂ€nge inte en speciell kvot för avancerade biodrivmedel. Det finns dock ett flertal planerade anlĂ€ggningar i Sverige som kan komma att bli stora producenter av avancerade biodrivmedel. TillgĂ€nglig pĂ„ https://f3centre.se/sv/samverkansprogram/  En delrapport frĂ„n ett projekt inom FĂRNYBARA DRIVMEDEL OCH SYSTEM 2018-2021. Ett samverkansprogram mellan Energimyndigheten och f3 Svenskt kunskapscentrum för förnybara drivmedel.</p
Assessing long-term sustainability of district heating systems
Biomass has become the main fuel for district heating (DH) systems in Sweden, and the substitution of biomass for oil during the last decades has led to considerably reduced CO2 emissions within the DH systems. Today, biomass is used both in heat- only boilers and, increasingly, in combined heat-and-power plants. District heating contributes also to increased sustainability through the utilization of industrial waste heat, which substitutes for primary energy use.With increasing pressure on constrained biomass resources and due to the geographical distribution of waste-heat sources, the municipal DH systems need to look for new solutions in order to further reduce their dependency on primary energy sources and enhance their sustainability. An integration of local systems into a regional heat system would allow for utilization of an increasing amount of waste heat, to capture scale effects of biomass combined heat and power plants and also to compensate for load profile differences between the local systems. DH systems are in addition being increasingly integrated with the power system and also with biorefineries through the production of bio transport fuels. Thus, the role of DH systems is becoming increasingly complex. This calls for new tools and methods to assess the sustainability of various possible future options and developments.The aim of the study is to assess the long-term sustainability of different DH developments with a focus on possibilities for integration of local DH systems into a regional system. In order to assess the sustainability in a long-term perspective of future DH options, we combine methods such as energy systems modeling and life cycle assessment in a procedural framework called life cycle sustainability assessment. The energy systems model applied is an optimizing bottom-up model. The study concerns the Vastra Gotaland region of Sweden and our model represents all the municipal DH systems at a detailed level. This presentation will mainly focus on the methodological aspects of the work: on how the different methods can be integrated and applied in a sustainability assessment of future district heating