| 1. |
- Larsson, Simon, et al.
(author)
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Reviewing electricity production cost assessments
- 2013
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In: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 30, s. 170-183
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Journal article (peer-reviewed)abstract
- A thorough review of twelve recent studies of production costs from different power generating technologies was conducted and a wide range in cost estimates was found. The reviewed studies show differences in their methodologies and assumptions, making the stated cost figures not directly comparable and unsuitable to be generalized to represent the costs for entire technologies. Moreover, current levelized costs of electricity methodologies focus only on the producer's costs, while additional costs viewed from a consumer perspective and on external costs with impact on society should be included if these results are to be used for planning. Although this type of electricity production cost assessments can be useful, the habit of generalizing electricity production cost figures for entire technologies is problematic. Cost escalations tend to occur rapidly with time, the impact of economies of scale is significant, costs are in many cases site-specific, and country-specific circumstances affect production costs. Assumptions on the cost-influencing factors such as discount rates, fuel prices and heat credits fluctuate considerably and have a significant impact on production cost results. Electricity production costs assessments similar to the studies reviewed in this work disregard many important cost factors, making them inadequate for decision and policy making, and should only be used to provide rough ballpark estimates with respect to a given system boundary. Caution when using electricity production cost estimates are recommended, and further studies investigating cost under different circumstances, both for producers and society as a whole are called for. Also, policy makers should be aware of the potentially widely different results coming from electricity production cost estimates under different assumptions.
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| 2. |
- Davidsson, Simon, et al.
(author)
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A review of life cycle assessments on wind energy systems
- 2012
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In: The International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 0948-3349 .- 1614-7502. ; 17:6, s. 729-742
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Research review (peer-reviewed)abstract
- PurposeSeveral life cycle assessments (LCA) of wind energy published in recent years are reviewed to identify methodological differences and underlying assumptions.MethodsA full comparative analysis of 12 studies were undertaken (10 peer-reviewed papers, 1 conference paper, 1 industry report) regarding six fundamental factors (methods used, energy use accounting, quantification of energy production, energy performance and primary energy, natural resources, and recycling). Each factor is discussed in detail to highlight strengths and shortcomings of various approaches.ResultsSeveral potential issues are found concerning the way LCA methods are used for assessing energy performance and environmental impact of wind energy, as well as dealing with natural resource use and depletion. The potential to evaluate natural resource use and depletion impacts from wind energy appears to be poorly exploited or elaborated on in the reviewed studies. Estimations of energy performance and environmental impacts are critically analyzed and found to differ significantly.Conclusions and recommendationsA continued discussion and development of LCA methodology for wind energy and other energy resources are encouraged. Efforts should be made to standardize methods and calculations. Inconsistent use of terminology and concepts among the analyzed studies are found and should be remedied. Different methods are generally used and the results are presented in diverse ways, making it hard to compare studies with each other, but also with other renewable energy sources.
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| 3. |
- Davidsson, Simon, et al.
(author)
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Growth curves and sustained commissioning modelling of renewable energy : Investigating resource constraints for wind energy
- 2014
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In: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 73, s. 767-776
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Journal article (peer-reviewed)abstract
- Abstract Several recent studies have proposed fast transitions to energy systems based on renewable energy technology. Many of them dismiss potential physical constraints and issues with natural resource supply, and do not consider the growth rates of the individual technologies needed or how the energy systems are to be sustained over longer time frames. A case study is presented modelling potential growth rates of the wind energy required to reach installed capacities proposed in other studies, taking into account the expected service life of wind turbines. A sustained commissioning model is proposed as a theoretical foundation for analysing reasonable growth patterns for technologies that can be sustained in the future. The annual installation and related resource requirements to reach proposed wind capacity are quantified and it is concluded that these factors should be considered when assessing the feasibility, and even the sustainability, of fast energy transitions. Even a sustained commissioning scenario would require significant resource flows, for the transition as well as for sustaining the system, indefinitely. Recent studies that claim there are no potential natural resource barriers or other physical constraints to fast transitions to renewable energy appear inadequate in ruling out these concerns.
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| 4. |
- Höök, Mikael, 1982-, et al.
(author)
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Decline and depletion rates of oil production : a comprehensive investigation
- 2014
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In: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 372:2006, s. 0120448-
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Journal article (peer-reviewed)abstract
- Two of the most fundamental concepts in the current debate about future oil supply are oil field decline rates and depletion rates. These concepts are related, but not identical. This paper clarifies the definitions of these concepts, summarises the underlying theory and empirically estimates decline and depletion rates for different categories of oil field. A database of 880 post-peak fields is analysed to determine typical depletion levels, depletion rates, and decline rates. This demonstrates that the size of oil fields has a significant influence on decline and depletion rates, with generally high values for small fields and comparatively low values for larger fields. These empirical findings have important implications for oil supply forecasting.
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| 5. |
- Jianliang, Wang, et al.
(author)
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Chinese coal supply and future production outlooks
- 2013
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In: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 60, s. 204-214
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Journal article (peer-reviewed)abstract
- China's energy supply is dominated by coal, making projections of future coal production in China important. Recent forecasts suggest that Chinese coal production may reach a peak in 2010–2039 but with widely differing peak production levels. The estimated URR (ultimately recoverable resources) influence these projections significantly, however, widely different URR-values were used due to poor understanding of the various Chinese coal classification schemes. To mitigate these shortcomings, a comprehensive investigation of this system and an analysis of the historical evaluation of resources and reporting issues are performed. A more plausible URR is derived, which indicates that many analysts underestimate volumes available for exploitation. Projections based on the updated URR using a modified curve-fitting model indicate that Chinese coal production could peak as early as 2024 at a maximum annual production of 4.1 Gt. By considering other potential constraints, it can be concluded that peak coal in China appears inevitable and immediate. This event can be expected to have significant impact on the Chinese economy, energy strategies and GHG (greenhouse gas) emissions reduction strategies.
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| 6. |
- Sällh, David, et al.
(author)
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Evaluation and update of Norwegian and Danish oil production forecasts and implications for Swedish oil import
- 2014
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In: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 65, s. 333-345
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Journal article (peer-reviewed)abstract
- This paper presents an updated historic oil production analysis as well as an updated future oil production forecast for Norway and Denmark. Previous forecasts conducted by academic and official agencies using a variety of methodologies are contrasted and their accuracy examined. The bottom-up field-by-field methodology is found to be precise in the short-term, as it deviates by less than 1% from actual production. The impact of declining oil production in the North Sea on Sweden is explored as a case study. The historic and future trends regarding Swedish oil imports are presented and their vulnerability assessed using the Herfindahl-Hirschman index.
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| 7. |
- Vikström, Hanna, 1985-, et al.
(author)
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Lithium availability and future production outlooks
- 2013
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 110:10, s. 252-266
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Journal article (peer-reviewed)abstract
- Lithium is a highly interesting metal, in part due to the increasing interest in lithium-ion batteries. Several recent studies have used different methods to estimate whether the lithium production can meet an increasing demand, especially from the transport sector, where lithium-ion batteries are the most likely technology for electric cars. The reserve and resource estimates of lithium vary greatly between different studies and the question whether the annual production rates of lithium can meet a growing demand is seldom adequately explained. This study presents a review and compilation of recent estimates of quantities of lithium available for exploitation and discusses the uncertainty and differences between these estimates. Also, mathematical curve fitting models are used to estimate possible future annual production rates. This estimation of possible production rates are compared to a potential increased demand of lithium if the International Energy Agency’s Blue Map Scenarios are fulfilled regarding electrification of the car fleet. We find that the availability of lithium could in fact be a problem for fulfilling this scenario if lithium-ion batteries are to be used. This indicates that other battery technologies might have to be implemented for enabling an electrification of road transports.
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| 8. |
- Walan, Petter, et al.
(author)
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Phosphate rock production and depletion : Regional disaggregated modeling and global implications
- 2014
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In: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 93, s. 178-187
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Journal article (peer-reviewed)abstract
- Abstract Numerous recent studies discuss phosphate rock extraction, and some even propose that a peak in production could be reached in coming decades. This would have great consequences as phosphate rock based fertilizers are irreplaceable in modern agriculture. Studies suggesting an impending peak commonly use curve fitting models where mathematical functions are fitted to historical world production data, while studies using other methods reach completely different results. Also, a sudden increase in global reserve estimates is commonly used to dismiss these warnings, and has somewhat altered the debate. The recent multiplication of estimated reserves is mostly based on an increase of the Moroccan reserve estimate, leading to Morocco currently making up most of the global reserves. This study models global phosphate rock production using a disaggregated curve fitting model based on the production in individual major producing countries, providing a somewhat different view than most studies, and show that the global trade of phosphate rock could be completely dependent on Morocco in the future. There are several different factors that can potentially limit global production and these factors should be considered for the individual producing countries. Society’s total dependence on phosphate rock should be further investigated despite claims of large resource occurrences.
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