| 1. |
- Eggert, Håkan, 1961, et al.
(författare)
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Promoting Second Generation Biofuels: Does the First Generation Pave the Road?
- 2014
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 7:7, s. 4430-4445
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Tidskriftsartikel (refereegranskat)abstract
- The U.S., Brazil and a number of European and other countries worldwide have introduced various support schemes for bioethanol and biodiesel. The advantage of these biofuels is that they are relatively easily integrated with the current fossil fuel-based transport sector, at least up to a certain point. However, recent studies point to various negative effects of expanding the production of first generation (1G) biofuels further. 1G biofuels’ problems can be overcome by a transition to second generation (2G) biofuels. So far, 2G biofuels are much more costly to produce. We therefore ask: to what extent is targeted support to 2G biofuels likely to bring costs down? Additionally, are current support schemes for biofuels well designed in order to promote the development of 2G biofuels? We find that the prospects for cost reduction look better for 2G bioethanol than for 2G biodiesel. Bioethanol made from cellulose is far from a ripe technology, with several cost-reducing opportunities yet to be developed. Hence, targeted support to cellulosic ethanol might induce a switch from 1G to 2G biofuels. However, we find little evidence that production and use of 1G bioethanol will bridge the conversion to 2G bioethanol. Hence, to the extent that private investment in the development of 2G bioethanol is too low, current support schemes for 1G biofuels may block 2G bioethanol instead of promoting it.
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| 2. |
- Karlsson, Ida, 1980, et al.
(författare)
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Roadmap for Decarbonization of the Building and Construction Industry - A Supply Chain Analysis Including Primary Production of Steel and Cement
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Sweden has committed to reducing greenhouse gas (GHG) emissions to net-zero by 2045. Around 20% of Sweden's annual CO(2)emissions arise from manufacturing, transporting, and processing of construction materials for construction and refurbishment of buildings and infrastructure. In this study, material and energy flows for building and transport infrastructure construction is outlined, together with a roadmap detailing how the flows change depending on different technical and strategical choices. By matching short-term and long-term goals with specific technology solutions, these pathways make it possible to identify key decision points and potential synergies, competing goals, and lock-in effects. The results show that it is possible to reduce CO(2)emissions associated with construction of buildings and transport infrastructure by 50% to 2030 applying already available measures, and reach close to zero emissions by 2045, while indicating that strategic choices with respect to process technologies and energy carriers may have different implications on energy use and CO(2)emissions over time. The results also illustrate the importance of intensifying efforts to identify and manage both soft and hard barriers and the importance of simultaneously acting now by implementing available measures (e.g., material efficiency and material/fuel substitution measures), while actively planning for long-term measures (low-CO(2)steel or cement).
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| 3. |
- Liu, Jiandong, et al.
(författare)
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An Improved ångström-type model for estimating solar radiation over the tibetan plateau
- 2017
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 by the authors. For estimating the annual mean of daily solar irradiation in plateau mountainous regions, observed data from 15 radiation stations were used to validate different empirical estimation methods over the Tibetan Plateau. Calibration indicates that sunshine-based site-dependent models perform better than temperature-based ones. Then, the highly rated sunshine-based Ångström model and temperature-based Bristow model were selected for regional application. The geographical models perform much better than the average models, but still not ideally. To achieve better performance, the Ångström-type model was improved using altitude and water vapor pressure as the leading factors. The improved model can accurately predict the coefficients at all the stations, and performs the best among all models with an average Nash-Sutcliffe Efficiency value of 0.856. Spatial distribution of the annual mean of daily solar irradiation was then estimated with the improved model. It is indicated that there is an increasing trend of radiation from east to west, with a great center of the annual mean of daily solar irradiation on southwest Tibetan Plateau ranging from 20 to 24 MJm2. The improved model should be further validated against observations before its applications in other plateau mountainous regions.
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| 4. |
- Mirzaei Alavijeh, Nima, 1993, et al.
(författare)
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Cost-Effectiveness of Carbon Emission Abatement Strategies for a Local Multi-Energy System - A Case Study of Chalmers University of Technology Campus
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the cost-effectiveness of operation strategies which can be used to abate CO2 emissions in a local multi-energy system. A case study is carried out using data from a real energy system that integrates district heating, district cooling, and electricity networks at Chalmers University of Technology. Operation strategies are developed using a mixed integer linear programming multi-objective optimization model with a short foresight rolling horizon and a year of data. The cost-effectiveness of different strategies is evaluated across different carbon prices. The results provide insights into developing abatement strategies for local multi-energy systems that could be used by utilities, building owners, and authorities. The optimized abatement strategies include: increased usage of biomass boilers, substitution of district heating and absorption chillers with heat pumps, and higher utilization of storage units. The results show that, by utilizing all the strategies, a 20.8% emission reduction can be achieved with a 2.2% cost increase for the campus area. The emission abatement cost of all strategies is 36.6–100.2 (€/tCO2 ), which is aligned with estimated carbon prices if the Paris agreement target is to be achieved. It is higher, however, than average European Emission Trading System prices and Sweden’s carbon tax in 2019.
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| 5. |
- Toktarova, Alla, 1992, et al.
(författare)
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Pathways for Low-Carbon Transition of the Steel Industry-A Swedish Case Study
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:15
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Tidskriftsartikel (refereegranskat)abstract
- The concept of techno-economic pathways is used to investigate the potential implementation of CO(2)abatement measures over time towards zero-emission steelmaking in Sweden. The following mitigation measures are investigated and combined in three pathways: top gas recycling blast furnace (TGRBF); carbon capture and storage (CCS); substitution of pulverized coal injection (PCI) with biomass; hydrogen direct reduction of iron ore (H-DR); and electric arc furnace (EAF), where fossil fuels are replaced with biomass. The results show that CCS in combination with biomass substitution in the blast furnace and a replacement primary steel production plant with EAF with biomass (Pathway 1) yield CO(2)emission reductions of 83% in 2045 compared to CO(2)emissions with current steel process configurations. Electrification of the primary steel production in terms of H-DR/EAF process (Pathway 2), could result in almost fossil-free steel production, and Sweden could achieve a 10% reduction in total CO(2)emissions. Finally, (Pathway 3) we show that increased production of hot briquetted iron pellets (HBI), could lead to decarbonization of the steel industry outside Sweden, assuming that the exported HBI will be converted via EAF and the receiving country has a decarbonized power sector.
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| 6. |
- Andersson, Viktor, 1994, et al.
(författare)
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A Novel Method for On-Line Characterization of Alkali Release and Thermal Stability of Materials Used in Thermochemical Conversion Processes
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 15:12
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Tidskriftsartikel (refereegranskat)abstract
- Alkali metal compounds are released during the thermal conversion of biofuels and fossil fuels and have a major impact on the efficiency of conversion processes. Herein, we describe a novel method for the simultaneous characterization of alkali release and mass loss from materials used in combustion and gasification processes including solid fuels, fluidized bed materials, and catalysts for gas reforming. The method combines the thermogravimetric analysis of selected samples with the on-line measurement of alkali release using a surface ionization detector. The technique builds on the careful treatment of alkali processes during transport from a sample to the downstream alkali monitor including the losses of alkali in the molecular form to hot walls, the formation of nanometer-sized alkali-containing particles during the cooling of exhaust gases, aerosol particle growth, and diffusion losses in sampling tubes. The performance of the setup was demonstrated using biomass samples and fluidized bed material from an industrial process. The emissions of alkali compounds during sample heating and isothermal conditions were determined and related to the simultaneous thermogravimetric analysis. The methodology was concluded to provide new evidence regarding the behavior of alkali in key processes including biomass pyrolysis and gasification and ash interactions with fluidized beds. The implications and further improvements of the technique are discussed.
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| 7. |
- Holmlid, Leif, 1942
(författare)
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Generator for Large Fluxes of Kaons and Pions Using Laser-Induced Nuclear Processes in Ultra-Dense Hydrogen H(0)
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 15:24
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced nuclear reactions in ultra-dense hydrogen H(0) produce mesons with both relatively low kinetic energy and with high kinetic energy. The kaons have up to 100 MeV of kinetic energy, thus a velocity of 0.55 c. Each laser pulse of >0.1 J of energy and length of 5 ns produces 1013 mesons. The operation of the meson generator is here demonstrated by measuring all decay times for mesons in the ns range after induction by a pulsed laser. These decay times are the unique fingerprints of the mesons, and they also produce the kinetic energy of the mesons created from their time-dilated decay. The charged pion decay time at rest from this generator is measured to be 25.92 ± 0.04 ns (standard fit error), in reasonable agreement with the tabulated results of 26.033 ns. A similar accuracy is found for the other mesons as for the charged kaons, with 96 MeV of kinetic energy, at 14.81 ± 0.05 ns. The same general behaviour is found with both deuterium and normal hydrogen forming the ultra-dense phase H(0) on the laser target. This meson generator gives intense meson showers useful for many types of particle physics experiments at a small fraction of the cost of using particle accelerators. A particle accelerator would need an energy of at least 1021 eV to produce a similar shower of 1013 mesons. Thus, the described generator is among the most intense meson sources that exist. Other important applications include nuclear energy generation and particle (pion) radiation for cancer treatment.
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| 8. |
- Williamsson, Jon, 1978
(författare)
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EV Charging on Ferries and in Terminals-A Business Model Perspective
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 15:18
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Tidskriftsartikel (refereegranskat)abstract
- Ferry operators in Sweden provide transportation for tens of millions of people annually. As electric vehicles (EVs) are becoming more commonplace, ferries and ferry terminals seem like suitable places for providing charging services. However, high costs and low occupancy rates means that it is challenging to design profitable business models for charging services in general. This paper reports on a market review of the charging services that ferry operators in Sweden provide and a case study of suitable business model design elements for operators that intend to offer charging on board or in terminals. While only two of fifteen ferry operators offer EV charging on board, four more operators indicated that they were planning to provide such services in the near future. Nine operators offered charging in or close to ferry terminals. The results also indicate that business model design focuses primarily on safety, leading to higher costs for onboard charging due to hardware and staffing costs. Investments also tend to incorporate costs which are not specific to onboard charging but rather the general safety requirements associated with EVs. Finally, poor profitability makes future development dependent on managerial efforts to reduce costs and improve revenue as well as supportive policies such as investment subsidies.
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| 9. |
- Yu, Quanjiang, 1990, et al.
(författare)
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Optimal preventive maintenance scheduling for wind turbines under condition monitoring
- 2024
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Ingår i: Energies. - 1996-1073 .- 1996-1073. ; 17:2
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy sources, such as wind and solar, are positioned to play a pivotal role in future energy systems. In this paper, we propose a mathematical model for calculating and regularly updating the next preventive maintenance plan for a wind farm. Our optimization criterion considers various factors, including the current ages of key components, major maintenance costs, eventual energy production losses, and available data monitoring the condition of the wind turbines. Employing Cox proportional hazards analysis, we develop a comprehensive approach that accounts for the current ages of critical components, significant maintenance costs, potential energy production losses, and data collected from monitoring the condition of wind turbines. We illustrate the effectiveness of our approach through a case study based on data collected from multiple wind farms in Sweden. Our results demonstrate that preventive maintenance planning yields positive effects, particularly when the wind turbine components in question have significantly shorter lifespans than the turbine itself.
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