8 research outputs found

    THE CLIMATE BENEFITS OF INCREASED FOREST BIOENERGY USE IN SWEDEN: EVALUATION AT DIFFERENT SCALES

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    Forest bioenergy has gained attention as an alternative to replace fossil fuels and mitigate climate change; however, in recent years its climate benefit has been questioned. The aim of this paper is to (i) present results from an assessment of the carbon (C) balance for Swedish bioenergy systems that use forest biomass from long-rotation forestry as feedstock; (ii) show how methodological choices and assumptions influence the outcome of the assessment; and (iii) discuss the climate effect of increasing forest harvest for energy use in Sweden. To achieve this purpose, an assessment framework is developed which consists of two linked models: the first one is the Q model, used to quantify the biogenic C balances associated with forest management and the second one is the CAfBio, used to account for forest product flows up to the point when the C is released into the atmosphere. Modeling results depend on many factors, with some important ones being harvest intensity, changes in forest management and the emissions intensity of the baseline scenario, which determines the C savings from using forest products. However, the results of the study support the conclusion that increased use of forest biomass for bioenergy can deliver substantial C savings

    Carbon balances of bioenergy systems using biomass from forests managed with long rotations: bridging the gap between stand and landscape assessments

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    Studies report different findings concerning the climate benefits of bioenergy, in part due to varying scope and use of different approaches to define spatial and temporal system boundaries. We quantify carbon balances for bioenergy systems that use biomass from forests managed with long rotations, employing different approaches and boundary conditions. Two approaches to represent landscapes and quantify their carbon balances - expanding vs. constant spatial boundaries - are compared. We show that for a conceptual forest landscape, constructed by combining a series of time-shifted forest stands, the two approaches sometimes yield different results. We argue that the approach that uses constant spatial boundaries is preferable because it captures all carbon flows in the landscape throughout the accounting period. The approach that uses expanding system boundaries fails to accurately describe the carbon fluxes in the landscape due to incomplete coverage of carbon flows and influence of the stand-level dynamics, which in turn arise from the way temporal system boundaries are defined on the stand level. Modelling of profit-driven forest management using location-specific forest data shows that the implications for carbon balance of management changes across the landscape ( which are partly neglected when expanding system boundaries are used) depend on many factors such as forest structure and forest owners\u27 expectations of market development for bioenergy and other wood products. Assessments should not consider forest-based bioenergy in isolation but should ideally 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. Due to uncertainties, we modelled several alternative scenarios for forest products markets. We recommend that future work consider alternative scenarios for other critical factors, such as policy options and energy technology pathways

    The climate effect of increased forest bioenergy use in Sweden: evaluation at different spatial and temporal scales

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    Bioenergy from boreal forests managed for productive purposes (e.g., pulp, timber) is commonly held to offer attractive options for climate change mitigation. However, this view has been challenged in recent years. Carbon balances, cumulative radiative forcing, and average global temperature change have been calculated for a variety of bioenergy management regimes in Swedish forests and the results support the view that an increased use of forest biomass for energy in Sweden can contribute to climate change mitigation, although methodological (e.g. spatial scales) and parameter value choices influence the results significantly. We show that the climate effect of forest-based bioenergy depends on the forest ecosystems and management, including biomass extraction for bioenergy and other products, and how this management changes in response to anticipated market demands; and on the energy system effects, which determine the fossil carbon displacement and other greenhouse gas (GHG) mitigation effects of using forest biomass for bioenergy and other purposes. The public and private sectors are advised to consider information from comprehensive analyses that provide insights about energy and forest systems in the context of evolving forest product markets, alternative policy options, and energy technology pathways in their decision-making processes

    Architecting cars as constituents of a system of systems

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    Future transportation systems will be a heterogeneous mix of items with varying connectivity and interoperability. A mix of new technologies and legacy systems will co-exist to realize a variety of scenarios involving not only connected cars but also road infrastructures, pedestrians, cyclists, etc. Future transportation systems can be seen as a System of Systems (SoS), where each constituent system - one of the units that compose an SoS - can act as a standalone system, but the cooperation among the constituent systems enables new emerging and promising scenarios. In this paper we investigate how to architect cars so that they can be constituents of future transportation systems. This work is realized in the context of two Swedish projects coordinated by Volvo Cars and involving some universities and research centers in Sweden and many suppliers of the OEM, including Autoliv, Arccore, Combitech, Cybercom, Knowit, Prevas, \uc5F-Technology, Semcom, and Qamcom
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