| 1. |
- Cintas Sanchez, Olivia, 1982, et al.
(författare)
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The climate effect of increased forest bioenergy use in Sweden: evaluation at different spatial and temporal scales
- 2016
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Ingår i: Wiley Interdisciplinary Reviews: Energy and Environment. - : Wiley. - 2041-8396 .- 2041-840X. ; 5:3, s. 351-369
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Hansson, Julia, 1978, et al.
(författare)
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The potential influence of sustainability criteria on the European Union pellets market—the example of Sweden
- 2016
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Ingår i: Wiley Interdisciplinary Reviews: Energy and Environment. - 2041-8396 .- 2041-840X. ; 5:4, s. 413-429
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of sustainability criteria for solid biomass/biofuels on the European Union (EU) or global level may influence the EU pellets market, e.g., by limiting the eligible biomass supply potential or specific pellet chains. This assessment focuses on greenhouse gas (GHG) emission reductions and the issue of sustainable forest management (SFM) for pellets potentially used in Sweden(for residential and/or industrial use). The paper includes (1) a literature review of recent studies addressing the impact of sustainability requirements (for solid biomass and/or liquid biofuels) on the bioenergy market, (2) a characterization of SFM conditions in potential pellets export countries and their capacity to enforce respective legislation, and (3) an assessment of GHG emissions for heat and electricity for the Swedish market from selected potential wood pellet chains (including torrefaction) and related GHG emissions reduction compared to fossil fuelsusing a life cycle assessment perspective. Most of the assessed wood pellet value chains will most likely be able to meet stringent sustainability requirements from a GHG perspective. Thus, the impact of near-term GHG emission reduction demands on the Swedish pellets market is limited. More specifically, we find that torrefaction may be advantageous for pellets imported over long distances (i.e.,over approximately 18,500 km). We conclude that demand for SFM related to solid biofuels will not have a significant or long-lasting effect on the market for Swedish pellets. The real impacts of sustainability requirements will howeverdepend on levels of ambition as well as the methodologies and systems boundaries applied in future systems.
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| 3. |
- Huertas-Hernando, D., et al.
(författare)
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Hydro power flexibility for power systems with variable renewable energy sources : An IEA Task 25 collaboration
- 2016
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley & Sons. - 2041-8396 .- 2041-840X.
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Tidskriftsartikel (refereegranskat)abstract
- Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.
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| 4. |
- Milligan, M., et al.
(författare)
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Capacity value assessments of wind power
- 2016
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley & Sons. - 2041-8396 .- 2041-840X.
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Tidskriftsartikel (refereegranskat)abstract
- This article describes some of the recent research into the capacity value of wind power. With the worldwide increase in wind power during the past several years, there is increasing interest and significance regarding its capacity value because this has a direct influence on the amount of other (nonwind) capacity that is needed. We build on previous reviews from IEEE and IEA Wind Task 25a and examine recent work that evaluates the impact of multiple-year data sets and the impact of interconnected systems on resource adequacy. We also provide examples that explore the use of alternative reliability metrics for wind capacity value calculations. We show how multiple-year data sets significantly increase the robustness of results compared to single-year assessments. Assumptions regarding the transmission interconnections play a significant role. To date, results regarding which reliability metric to use for probabilistic capacity valuation show little sensitivity to the metric. For further resources related to this article, please visit the WIREs website.
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| 5. |
- Stupak, I, et al.
(författare)
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A global survey of stakeholder views and experiences for systems needed to effectively and efficiently govern sustainability of bioenergy
- 2016
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Ingår i: Wiley Interdisciplinary Reviews: Energy and Environment. - : Wiley. - 2041-8396 .- 2041-840X. ; 5:1, s. 89-118
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Forskningsöversikt (refereegranskat)abstract
- Different governance mechanisms have emerged to ensure biomass and bioenergy sustainability amidst a myriad of related public and private regulations that have existed for decades. We conducted a global survey with 59 questions which examined 192 stakeholders' views and experiences related to (1) the multi-leveled governance to which they are subjected, (2) the impacts of that governance on bioenergy production and trade, and (3) the most urgent areas for improvement of certification schemes. The survey revealed significant support along the whole supply chain for new legislation which uses market-based certification schemes to demonstrate compliance (co-regulation). Some respondents did not see a need for new regulation, and meta-standards is a promising approach for bridging divergent views, especially if other proof than certification will be an option. Most respondents had so far experienced positive or neutral changes to their bioenergy production or trade after the introduction of new sustainability governance. Legislative requirements and a green business profile were important motivations for getting certified, while lack of market advantages, administrative complexity and costs all were barriers of varying importance. A need to include, e.g., regular standard revision and dealing with conflicting criteria was identified by respondents associated with bioenergy schemes. Respondents associated with forestry schemes saw less need for revisions, but some were interested in supply chain sustainability criteria. Significant differences among schemes suggest it is crucial in the future to examine the tradeoffs between certification costs, schemes' inclusiveness, the quality of their substantive and procedural rules, and the subsequent effectiveness on-the-ground.
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| 6. |
- Söder, Lennart
(författare)
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Simplified analysis of balancing challenges in sustainable and smart energy systems with 100% renewable power supply
- 2016
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley & Sons. - 2041-8396 .- 2041-840X. ; 5:4, s. 401-412
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Tidskriftsartikel (refereegranskat)abstract
- In a power system, the basic physical law states that the total production is always exactly the same as total consumption. This physical law is always fulfilled no matter the type of power plants in the power system. In a power system with large shares of solar and wind power, this means that the other power plants have to fill the gap between actual solar plus wind power and the demand during each second/minute/hour. However, if there are large amounts of solar and wind power, then sometimes the available power from solar and wind exceeds the demand. In a future system based on large shares of solar and wind power, all these different situations have to be handled, and the question is how to analyze this. Three different methods concerning how to analyze systems with large shares of solar and wind power will be presented. The methods are applied to a Swedish case with close to 100% renewable power based on hydro, solar, wind and, bio-fuelled combined heat and power (CHP). This study shows that there are limited balancing costs for this case. The costs for curtailment of surplus as well as to keep enough capacity to cover a high load combined with low solar and low wind is comparatively small, below 0.3 Eurocent/kWh. However, more detailed studies are needed to quantify the exact cost under different conditions, but this study indicates the size of the challenges.
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