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  • 1.
    Abbas, Khizra
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Nee, Hans-Peter
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Autonomous Gate Drivers Tailored for Triangular Current Mode-Based Zero-Voltage Switching Two-Level Three-Phase Inverters for Electric Vehicle Drive Systems2024Ingår i: Energies, E-ISSN 1996-1073, Vol. 17, nr 5, artikel-id 1060Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The demand for highly efficient and dynamic electric vehicles (EVs) has increased dramatically. The traction inverter, a pivotal component in an EV powertrain, plays a crucial role. This study is dedicated to designing a traction inverter with focus on achieving high efficiency and elevated power density and mitigating electromagnetic interference (EMI) issues. To realize these objectives, autonomous gate drivers (AGDs) are proposed and designed using LTspice simulation software. The aim is to achieve zero voltage switching (ZVS) at both turn-on and turn-off through the utilization of triangular current mode (TCM) control on the gate driver. The AGDs implement a current modulation scheme by sensing the current and voltage and generating gate-source voltage signals with minimal delays. The implemented current modulation scheme by the AGDs results in an efficiency exceeding 99% for a 10 kW power rating. The sinusoidal output waveforms not only contribute to extending the motor lifespan by mitigating sharp-edge voltages but also bring advantages such as reduced switch stress, decreased EMI, and simplified thermal management.

  • 2.
    Acosta, Martha N.
    et al.
    School of Mechanical and Electrical Engineering, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 66455, NL, Mexico.
    Gonzalez-Longatt, Francisco
    Department of Electrical Engineering, Information Technology and Cybernetics, University of South-Eastern Norway, 3918 Porsgrunn, Norway.
    Andrade, Manuel A.
    School of Mechanical and Electrical Engineering, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 66455, NL, Mexico.
    Rueda Torres, Jose Luis
    Electrical Sustainable Energy Group, Department of Electrical Sustainable Energy, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, 2628 Delft, CD, The Netherlands.
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Assessment of Daily Cost of Reactive Power Procurement by Smart Inverters2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 16, artikel-id 4834Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reactive power control mechanisms at the smart inverters will affect the voltage profile, active power losses and the cost of reactive power procurement in a different way. Therefore, this paper presents an assessment of the cost–benefit relationship obtained by enabling nine different reactive power control mechanisms at the smart inverters. The first eight reactive power control mechanisms are available in the literature and include the IEEE 1547−2018 standard requirements. The ninth control mechanism is an optimum reactive power control proposed in this paper. It is formulated to minimise the active power losses of the network and ensure the bus voltages and the reactive power of the smart inverter are within their allowable limits. The Vestfold and Telemark distribution network was implemented in DIgSILENT PowerFactory and used to evaluate the reactive power control mechanisms. The reactive power prices were taken from the default payment rate document of the National Grid. Simulation results demonstrate that the optimal reactive power control mechanism provides the best cost–benefit for the daily steady-state operation of the network.

  • 3.
    Aljure, Mauricio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Becerra Garcia, Marley
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Karlsson, Mattias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Erratum to: Aljure, M.; Becerra, M.; Karlsson, E.M. Streamer inception from ultra-sharp needles in mineral oil based nanofluids2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 11, artikel-id 2900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The authors wish to make the following corrections to their paper [1]: i. On pages 13 and 14, the numbering of references from 17 to 30 is incorrect. References 17 to 30 should be renumbered from the original order below: 17. Liu, Z.; Liu, Q.; Wang, Z.D.; Jarman, P.; Krause, C.; Smith, P.W.R.; Gyore, A. Partial discharge behaviour of transformer liquids and the influence of moisture content. In Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids (ICDL), Bled, Slovenia, 29 June–3 July 2014. 18. Yamashita, H.; Yamazawa, K.; Wang, Y.S. The effect of tip curvature on the prebreakdown streamer structure in cyclohexane. IEEE Trans. Dielectr. Electr. Insul. 1998, 5, 396–401. 19. Dumitrescu, L.; Lesaint, O.; Bonifaci, N.; Denat, A.; Notingher, P. Study of streamer inception in cyclohexane with a sensitive charge measurement technique under impulse voltage. J. Electrostat. 2001, 53, 135–146. 20. Pourrahimi, A.M.; Hoang, T.A.; Liu, D.; Pallon, L.K.H.; Gubanski, S.; Olsson, R.T.; Gedde, U.W.; Hedenqvist, M.S. Highly efficient interfaces in nanocomposites based on polyethylene and ZnO nano/hierarchical particles: A novel approach toward ultralow electrical conductivity insulations. Adv. Mater. 2016, 28, 8651–8657. 21. Li, J.; Du, B.; Wang, F.; Yao, W.; Yao, S. The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids. Phys. Lett. A 2016, 380, 604–608. 22. Aljure, M.; Becerra, M.; Pallon, L.K.H. Electrical conduction currents of a mineral oil-based nanofluid in needle-plane configuration. In Proceedings of the 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Toronto, ON, Canada, 16–19 October 2016; pp. 687–690. 23. Primo, V.A.; Garcia, B.; Albarracin, R. Improvement of transformer liquid insulation using nanodielectric fluids: A review. IEEE Electr. Insul. Mag. 2018, 34, 13–26. 24. Jin, H.; Andritsch, T.; Morshuis, P.H.F.; Smit, J.J. AC breakdown voltage and viscosity of mineral oil based SiO2 nanofluids. In Proceedings of the 2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Montreal, QC, Canada, 14–17 October 2012; pp. 902–905. 25. Jin, H.; Morshuis, P.; Mor, A.R.; Smit, J.J.; Andritsch, T. Partial discharge behavior of mineral oil based nanofluids. IEEE Trans. Dielectr. Electr. Insul. 2015, 22, 2747–2753. 26. Du, Y.; Lv, Y.; Li, C.; Chen, M.; Zhong, Y.; Zhou, J.; Li, X.; Zhou, Y. Effect of semiconductive nanoparticles on insulating performances of transformer oil. IEEE Trans. Dielectr. Electr. Insul. 2012, 19, 770–776. 27. Dung, N.V.; Høidalen, H.K.; Linhjell, D.; Lundgaard, L.E.; Unge, M. Effects of reduced pressure and additives on streamers in white oil in long point-plane gap. J. Phys. D Appl. Phys. 2013, 46, 255501. 28. McCool, J.I. Using the Weibull Distribution; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2012. 29. Lesaint, O.L.; Top, T.V. Streamer initiation in mineral oil. part I: Electrode surface effect under impulse voltage. IEEE Trans. Dielectr. Electr. Insul. 2002, 9, 84–91. 30. Becerra, M.; Frid, H.; Vázquez, P.A. Self-consistent modeling of laminar electrohydrodynamic plumes from ultra-sharp needles in cyclohexane. Phys. Fluids 2017, 29, 123605. to the following, corrected numbering: 17. Dumitrescu, L.; Lesaint, O.; Bonifaci, N.; Denat, A.; Notingher, P. Study of streamer inception in cyclohexane with a sensitive charge measurement technique under impulse voltage. J. Electrostat. 2001, 53, 135–146. 18. Liu, Z.; Liu, Q.; Wang, Z.D.; Jarman, P.; Krause, C.; Smith, P.W.R.; Gyore, A. Partial discharge behaviour of transformer liquids and the influence of moisture content. In Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids (ICDL), Bled, Slovenia, 29 June–3 July 2014. 19. Yamashita, H.; Yamazawa, K.; Wang, Y.S. The effect of tip curvature on the prebreakdown streamer structure in cyclohexane. IEEE Trans. Dielectr. Electr. Insul. 1998, 5, 396–401. 20. Becerra, M.; Frid, H.; Vázquez, P.A. Self-consistent modeling of laminar electrohydrodynamic plumes from ultra-sharp needles in cyclohexane. Phys. Fluids 2017, 29, 123605. 21. Pourrahimi, A.M.; Hoang, T.A.; Liu, D.; Pallon, L.K.H.; Gubanski, S.; Olsson, R.T.; Gedde, U.W.; Hedenqvist, M.S. Highly efficient interfaces in nanocomposites based on polyethylene and ZnO nano/hierarchical particles: A novel approach toward ultralow electrical conductivity insulations. Adv. Mater. 2016, 28, 8651–8657. 22. Li, J.; Du, B.; Wang, F.; Yao, W.; Yao, S. The effect of nanoparticle surfactant polarization on trapping depth of vegetable insulating oil-based nanofluids. Phys. Lett. A 2016, 380, 604–608. 23. Aljure, M.; Becerra, M.; Pallon, L.K.H. Electrical conduction currents of a mineral oil-based nanofluid in needle-plane configuration. In Proceedings of the 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Toronto, ON, Canada, 16–19 October 2016; pp. 687–690. 24. Primo, V.A.; Garcia, B.; Albarracin, R. Improvement of transformer liquid insulation using nanodielectric fluids: A review. IEEE Electr. Insul. Mag. 2018, 34, 13–26. 25. Jin, H.; Andritsch, T.; Morshuis, P.H.F.; Smit, J.J. AC breakdown voltage and viscosity of mineral oil based SiO2 nanofluids. In Proceedings of the 2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Montreal, QC, Canada, 14–17 October 2012; pp. 902–905. 26. Jin, H.; Morshuis, P.; Mor, A.R.; Smit, J.J.; Andritsch, T. Partial discharge behavior of mineral oil based nanofluids. IEEE Trans. Dielectr. Electr. Insul. 2015, 22, 2747–2753. 27. Du, Y.; Lv, Y.; Li, C.; Chen, M.; Zhong, Y.; Zhou, J.; Li, X.; Zhou, Y. Effect of semiconductive nanoparticles on insulating performances of transformer oil. IEEE Trans. Dielectr. Electr. Insul. 2012, 19, 770–776. 28. Dung, N.V.; Høidalen, H.K.; Linhjell, D.; Lundgaard, L.E.; Unge, M. Effects of reduced pressure and additives on streamers in white oil in long point-plane gap. J. Phys. D Appl. Phys. 2013, 46, 255501. 29. McCool, J.I. Using the Weibull Distribution; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2012. 30. Lesaint, O.L.; Top, T.V. Streamer initiation in mineral oil. part I: Electrode surface effect under impulse voltage. IEEE Trans. Dielectr. Electr. Insul. 2002, 9, 84–91. ii. On the last paragraph of page 9, the last sentence should be changed from: However, the results in [11] also show the consistent increase in the initiation voltage of prebreakdown phenomena in both polarities, as reported in Figure 11. to the following, corrected version: However, the results in [26] also show the consistent increase in the initiation voltage of prebreakdown phenomena in both polarities, as reported in Figure 11. iii. On the last paragraph of page 10, the third sentence should be changed from: Even though the existing hypotheses of the dielectric effect of NPs [8–10] were proposed for blunter electrodes (where charge generation before streamer initiation is less important [30]), they should still apply under the experimental conditions here reported. to the following, corrected version: Even though the existing hypotheses of the dielectric effect of NPs [5,6,16] were proposed for blunter electrodes (where charge generation before streamer initiation is less important [30]), they should still apply under the experimental conditions here reported. The authors would like to apologize for any inconvenience caused to the readers by these changes. The changes do not affect the scientific results. The manuscript will be updated and the original will remain online on the article webpage, with a reference to this Correction.

  • 4.
    Aljure, Mauricio
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Becerra Garcia, Marley
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Karlsson, Mattias E.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Streamer Inception from Ultra-Sharp Needles in Mineral Oil Based Nanofluids2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 8, artikel-id 2064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Positive and negative streamer inception voltages from ultra-sharp needle tips (with tip radii below 0.5 m) are measured in TiO2, SiO2, Al2O3, ZnO and C-60 nanofluids. The experiments are performed at several concentrations of nanoparticles dispersed in mineral oil. It is found that nanoparticles influence positive and negative streamers in different ways. TiO2, SiO2 and Al2O3 nanoparticles increase the positive streamer inception voltage only, whilst ZnO and C-60 nanoparticles augment the streamer inception voltages in both polarities. Using these results, the main hypotheses explaining the improvement in the dielectric strength of the host oil due to the presence of nanoparticles are analyzed. It is found that the water adsorption hypothesis of nanoparticles is consistent with the increments in the reported positive streamer inception voltages. It is also shown that the hypothesis of nanoparticles reducing the electron velocity by hopping transport mechanisms fails to explain the results obtained for negative streamers. Finally, the hypothesis of nanoparticles attaching electrons according to their charging characteristics is found to be consistent with the results hereby presented on negative streamers.

  • 5.
    Alsabery, Ammar I.
    et al.
    Islamic Univ, Refrigerat & Air Conditioning Tech Engn Dept, Coll Tech Engn, Najaf 54001, Iraq.;Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Bangi Selangor 43600, Malaysia..
    Hashim, Ishak
    Univ Kebangsaan Malaysia, Fac Sci & Technol, Dept Math Sci, Bangi Selangor 43600, Malaysia..
    Hajjar, Ahmad
    Univ Lyon, ECAM Lyon, LabECAM, F-69007 Lyon, France..
    Ghalambaz, Mohammad
    Ton Duc Thang Univ, Metamat Biomech & Multiphys Applicat Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Sci Appl, Ho Chi Minh City 758307, Vietnam..
    Nadeem, Sohail
    Ton Duc Thang Univ, Math & Its Applicat Life Sci Res Grp, Ho Chi Minh City 758307, Vietnam.;Ton Duc Thang Univ, Fac Math & Stat, Ho Chi Minh City 758307, Vietnam..
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. Shahid Bahonar Univ Kerman, Dept Mech Engn, Kerman 7616914111, Iran..
    Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks2020Ingår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 11, artikel-id 2942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present investigation addressed the entropy generation, fluid flow, and heat transferregarding Cu-Al2O3-water hybrid nanofluids into a complex shape enclosure containing a hot-halfpartition were addressed. The sidewalls of the enclosure are made of wavy walls including coldisothermal temperature while the upper and lower surfaces remain insulated. The governingequations toward conservation of mass, momentum, and energy were introduced into the formof partial differential equations. The second law of thermodynamic was written for the friction andthermal entropy productions as a function of velocity and temperatures. The governing equationsoccurred molded into a non-dimensional pattern and explained through the finite element method.Outcomes were investigated for Cu-water, Al2O3-water, and Cu-Al2O3-water nanofluids to addressthe effect of using composite nanoparticles toward the flow and temperature patterns and entropygeneration. Findings show that using hybrid nanofluid improves the Nusselt number comparedto simple nanofluids. In the case of low Rayleigh numbers, such enhancement is more evident.Changing the geometrical aspects of the cavity induces different effects toward the entropy generationand Bejan number. Generally, the global entropy generation for Cu-Al2O3-water hybrid nanofluidtakes places between the entropy generation values regarding Cu-water and Al2O3-water nanofluids.

  • 6.
    Andersson, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Application of Liquid Hydrogen Carriers in Hydrogen Steelmaking2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 5, s. 1392-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Steelmaking is responsible for approximately one third of total industrial carbon dioxide (CO2) emissions. Hydrogen (H2) direct reduction (H-DR) may be a feasible route towards the decarbonization of primary steelmaking if H2 is produced via electrolysis using fossil-free electricity. However, electrolysis is an electricity-intensive process. Therefore, it is preferable that H2 is predominantly produced during times of low electricity prices, which is enabled by the storage of H2. This work compares the integration of H2 storage in four liquid carriers, methanol (MeOH), formic acid (FA), ammonia (NH3) and perhydro-dibenzyltoluene (H18-DBT), in H-DR processes. In contrast to conventional H2 storage methods, these carriers allow for H2 storage in liquid form at moderate overpressures, reducing the storage capacity cost. The main downside to liquid H2 carriers is that thermochemical processes are necessary for both the storage and release processes, often with significant investment and operational costs. The carriers are compared using thermodynamic and economic data to estimate operational and capital costs in the H-DR context considering process integration options. It is concluded that the use of MeOH is promising compared to the other considered carriers. For large storage volumes, MeOH-based H2 storage may also be an attractive option to the underground storage of compressed H2. The other considered liquid H2 carriers suffer from large thermodynamic barriers for hydrogenation (FA) or dehydrogenation (NH3, H18-DBT) and higher investment costs. However, for the use of MeOH in an H-DR process to be practically feasible, questions regarding process flexibility and the optimal sourcing of CO2 and heat must be answered

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  • 7.
    Arnaudo, Monica
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Topel, Monika
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Vehicle-to-grid for peak shaving to unlock the integration of distributed heat pumps in a swedish neighborhood2020Ingår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 7, artikel-id en13071705Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The city of Stockholm is close to hitting the capacity limits of its power grid. As an additional challenge, electricity has been identified as a key resource to help the city to meet its environmental targets. This has pushed citizens to prefer power-based technologies, like heat pumps and electric vehicles, thus endangering the stability of the grid. The focus of this paper is on the district of Hammarby Sjöstad. Here, plans are set to switch from district heating to heat pumps. A previous study verified that this choice will cause overloadings on the electricity distribution grid. The present paper tackles this problem by proposing a new energy storage option. By considering the increasing share of electric vehicles, the potential of using the electricity stored in their batteries to support the grid is explored through technical performance simulations. The objective was to enable a bi-directional flow and use the electric vehicles' (EVs)' discharging to shave the peak demand caused by the heat pumps. It was found that this solution can eliminate overloadings up to 50%, with a 100% EV penetration. To overcome the mismatch between the availability of EVs and the overloadings' occurrence, the minimum state of charge for discharging should be lower than 70%.

  • 8.
    Arushanyan, Yevgeniya
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centre for Sustainable Communications, CESC.
    Björklund, Anna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Miljöstrategisk analys (fms).
    Eriksson, Ola
    Finnveden, Göran
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Soderman, Maria Ljunggren
    Sundqvist, Jan-Olov
    Stenmarck, Asa
    Environmental Assessment of Possible Future Waste Management Scenarios2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 2, artikel-id 247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Waste management has developed in many countries and will continue to do so. Changes towards increased recovery of resources in order to meet climate targets and for society to transition to a circular economy are important driving forces. Scenarios are important tools for planning and assessing possible future developments and policies. This paper presents a comprehensive life cycle assessment (LCA) model for environmental assessments of scenarios and waste management policy instruments. It is unique by including almost all waste flows in a country and also allow for including waste prevention. The results show that the environmental impacts from future waste management scenarios in Sweden can differ a lot. Waste management will continue to contribute with environmental benefits, but less so in the more sustainable future scenarios, since the surrounding energy and transportation systems will be less polluting and also because less waste will be produced. Valuation results indicate that climate change, human toxicity and resource depletion are the most important environmental impact categories for the Swedish waste management system. Emissions of fossil CO2 from waste incineration will continue to be a major source of environmental impacts in these scenarios. The model is used for analyzing environmental impacts of several policy instruments including weight based collection fee, incineration tax, a resource tax and inclusion of waste in a green electricity certification system. The effect of the studied policy instruments in isolation are in most cases limited, suggesting that stronger policy instruments as well as combinations are necessary to reach policy goals as set out in for example the EU action plan on circular economy.

  • 9.
    Astero, Poria
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik. State University of New York (SUNY) Korea, Korea; Stony Brook University, USA.
    Choi, Bong Jun
    Electrical Market Management Considering Power System Constraints in Smart Distribution Grids2016Ingår i: Energies, E-ISSN 1996-1073, Vol. 9, nr 6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rising demand, climate change, growing fuel costs, outdated power system infrastructures, and new power generation technologies have made renewable distribution generators very attractive in recent years. Because of the increasing penetration level of renewable energy sources in addition to the growth of new electrical demand sectors, such as electrical vehicles, the power system may face serious problems and challenges in the near future. A revolutionary new power grid system, called smart grid, has been developed as a solution to these problems. The smart grid, equipped with modern communication and computation infrastructures, can coordinate different parts of the power system to enhance energy efficiency, reliability, and quality, while decreasing the energy cost. Since conventional distribution networks lack smart infrastructures, much research has been recently done in the distribution part of the smart grid, called smart distribution grid (SDG). This paper surveys contemporary literature in SDG from the perspective of the electricity market in addition to power system considerations. For this purpose, this paper reviews current demand side management methods, supply side management methods, and electrical vehicle charging and discharging techniques in SDG and also discusses their drawbacks. We also present future research directions to tackle new and existing challenges in the SDG.

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    SG
  • 10.
    Astero, Poria
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik. State University of New York, USA.
    Choi, Bong Jun
    Liang, Hao
    Söder, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Transactive Demand Side Management Programs in Smart Grids with High Penetration of EVs2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 10, artikel-id 1640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to environmental concerns, economic issues, and emerging new loads, such as electrical vehicles (EVs), the importance of demand side management (DSM) programs has increased in recent years. DSM programs using a dynamic real-time pricing (RTP) method can help to adaptively control the electricity consumption. However, the existing RTP methods, particularly when they consider the EVs and the power system constraints, have many limitations, such as computational complexity and the need for centralized control. Therefore, a new transactive DSM program is proposed in this paper using an imperfect competition model with high EV penetration levels. In particular, a heuristic two-stage iterative method, considering the influence of decisions made independently by customers to minimize their own costs, is developed to find the market equilibrium quickly in a distributed manner. Simulations in the IEEE 37-bus system with 1141 customers and 670 EVs are performed to demonstrate the effectiveness of the proposed method. The results show that the proposed method can better manage the EVs and elastic appliances than the existing methods in terms of power constraints and cost. Also, the proposed method can solve the optimization problem quick enough to run in real-time.

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  • 11.
    Behi, Hamidreza
    et al.
    Vrije Univ Brussel, Res Grp MOBI Mobil, Logist & Automot Technol Res Ctr, Pleinlaan,2, B-1050 Brussels, Belgium.;Flanders Make, B-3001 Heverlee, Belgium..
    Behi, Mohammadreza
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Univ Sydney, Inst Photon & Optic Sci, Sch Phys, Sydney, NSW 2006, Australia..
    Ghanbarpour, Ali
    Babol Univ Technol, Sch Mech Engn, Babol 47134, Iran..
    Karimi, Danial
    Vrije Univ Brussel, Res Grp MOBI Mobil, Logist & Automot Technol Res Ctr, Pleinlaan,2, B-1050 Brussels, Belgium.;Flanders Make, B-3001 Heverlee, Belgium..
    Azad, Aryan
    Middle East Tech Univ METU, Dept Met & Mat Engn, TR-06800 Ankara, Turkey..
    Ghanbarpour, Morteza
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Behnia, Masud
    Macquarie Univ, Macquarie Business Sch, Sydney, NSW 1020, Australia..
    Enhancement of the Thermal Energy Storage Using Heat-Pipe-Assisted Phase Change Material2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 19, artikel-id 6176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Usage of phase change materials' (PCMs) latent heat has been investigated as a promising method for thermal energy storage applications. However, one of the most common disadvantages of using latent heat thermal energy storage (LHTES) is the low thermal conductivity of PCMs. This issue affects the rate of energy storage (charging/discharging) in PCMs. Many researchers have proposed different methods to cope with this problem in thermal energy storage. In this paper, a tubular heat pipe as a super heat conductor to increase the charging/discharging rate was investigated. The temperature of PCM, liquid fraction observations, and charging and discharging rates are reported. Heat pipe effectiveness was defined and used to quantify the relative performance of heat pipe-assisted PCM storage systems. Both experimental and numerical investigations were performed to determine the efficiency of the system in thermal storage enhancement. The proposed system in the charging/discharging process significantly improved the energy transfer between a water bath and the PCM in the working temperature range of 50 & DEG;C to 70 & DEG;C.</p>

  • 12. Bessa, Ricardo J.
    et al.
    Mohlen, Corinna
    Fundel, Vanessa
    Siefert, Malte
    Browell, Jethro
    El Gaidi, Sebastian Haglund
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Hodge, Bri-Mathias
    Cali, Umit
    Kariniotakis, George
    Towards Improved Understanding of the Applicability of Uncertainty Forecasts in the Electric Power Industry2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 9, artikel-id 1402Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Around the world wind energy is starting to become a major energy provider in electricity markets, as well as participating in ancillary services markets to help maintain grid stability. The reliability of system operations and smooth integration of wind energy into electricity markets has been strongly supported by years of improvement in weather and wind power forecasting systems. Deterministic forecasts are still predominant in utility practice although truly optimal decisions and risk hedging are only possible with the adoption of uncertainty forecasts. One of the main barriers for the industrial adoption of uncertainty forecasts is the lack of understanding of its information content (e.g., its physical and statistical modeling) and standardization of uncertainty forecast products, which frequently leads to mistrust towards uncertainty forecasts and their applicability in practice. This paper aims at improving this understanding by establishing a common terminology and reviewing the methods to determine, estimate, and communicate the uncertainty in weather and wind power forecasts. This conceptual analysis of the state of the art highlights that: (i) end-users should start to look at the forecast's properties in order to map different uncertainty representations to specific wind energy-related user requirements; (ii) a multidisciplinary team is required to foster the integration of stochastic methods in the industry sector. A set of recommendations for standardization and improved training of operators are provided along with examples of best practices.

  • 13.
    Beza, Abebe Dress
    et al.
    Bahir Dar Univ, Fac Civil & Water Resources Engn, Bahir Dar Inst Technol, POB 26, Bahir Dar, Ethiopia.;Univ Mons, Fac Engn, B-7000 Mons, Belgium..
    Zefreh, Mohammad Maghrour
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Transportplanering.
    Torok, Adam
    Budapest Univ Technol & Econ, Dept Transport Technol & Econ, H-1111 Budapest, Hungary.;KTI Inst Transport Sci, Dept Transport Policy & Econ, H-1111 Budapest, Hungary..
    Impacts of Different Types of Automated Vehicles on Traffic Flow Characteristics and Emissions: A Microscopic Traffic Simulation of Different Freeway Segments2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 18, artikel-id 6669Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different types of automated vehicles (AVs) have emerged promptly in recent years, each of which might have different potential impacts on traffic flow and emissions. In this paper, the impacts of autonomous automated vehicles (AAVs) and cooperative automated vehicles (CAVs) on capacity, average traffic speed, average travel time per vehicle, and average delay per vehicle, as well as traffic emissions such as carbon dioxide (CO2), nitrogen oxides (NOx), and particulate matter (PM10) have been investigated through a microsimulation study in VISSIM. Moreover, the moderating effects of different AV market penetration, and different freeway segments on AV's impacts have been studied. The simulation results show that CAVs have a higher impact on capacity improvement regardless of the type of freeway segment. Compared to other scenarios, CAVs at 100% market penetration in basic freeway segments have a greater capacity improvement than AAVs. Furthermore, merging, diverging, and weaving segments showed a moderating effect on capacity improvements, particularly on CAVs' impact, with merging and weaving having the highest moderating effect on CAVs' capacity improvement potential. Taking average delay per vehicle, average traffic speed, and average travel time per vehicle into account, simulation results were diverse across the investigated scenarios. The emission estimation results show that 100% AAV scenarios had the best performance in emission reductions in basic freeway and merging sections, while other scenarios increased emissions in diverging and weaving sections.

  • 14.
    Bhadoria, Shubhangi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik. State Key Laboratory of Electrical Insulation and Power Equipment, Xi′an Jiaotong University, Xi′an 710049, China.
    Dijkhuizen, Fransv
    Hitachi Energy Research, 72178 Västerås, Sweden.
    Zhang, Xu
    Ran, Li
    Nee, Hans-Peter
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Over-Current Capability of Silicon Carbide and Silicon Devices for Short Power Pulses with Copper and Phase Change Materials below the Chip2024Ingår i: Energies, E-ISSN 1996-1073, Vol. 17, nr 2, s. 462-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An increasing share of fluctuating and intermittent renewable energy sources can cause over-currents (OCs) in the power system. The heat generated during OCs increases the junction temperature of semiconductor devices and could even lead to thermal runaway if thermal limits are reached. In order to keep the junction temperature within the thermal limit of the semiconductor, the power module structure with heat-absorbing material below the chip is investigated through COMSOL Multiphysics simulations. The upper limits of the junction temperature for Silicon (Si) and Silicon Carbide (SiC) are assumed to be 175 and 250 ∘∘C, respectively. The heat-absorbing materials considered for analysis are a copper block and a copper block with phase change materials (PCMs). Two times, three times, and four times of OCs would be discussed for durations of a few hundred milliseconds and seconds. This article also discusses the thermal performance of a copper block and a copper block with PCMs. PCMs used for Si and SiC are LM108 and Lithium, respectively. It is concluded that the copper block just below the semiconductor chip would enable OC capability in Si and SiC devices and would be more convenient to manufacture as compared to the copper block with PCM.

  • 15.
    Bitsi, Konstantina
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Bosga, Sjoerd
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik. ABB Corporate Research, 722 26 Västerås, Sweden.
    Wallmark, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Design Aspects and Performance Evaluation of Pole-Phase Changing Induction Machines2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 19, s. 7012-7012Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
    fulltext
  • 16.
    Borenius, Seppo
    et al.
    Aalto Univ, Sch Elect Engn, Dept Commun & Networking, Espoo 02150, Finland..
    Gopalakrishnan, Pavithra
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik. Aalto Univ, Sch Elect Engn, Dept Commun & Networking, Espoo 02150, Finland..
    Bertling Tjernberg, Lina
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Kantola, Raimo
    Aalto Univ, Sch Elect Engn, Dept Commun & Networking, Espoo 02150, Finland..
    Expert-Guided Security Risk Assessment of Evolving Power Grids2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 9, s. 3237-, artikel-id 3237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electric power grids, which form an essential part of the critical infrastructure, are evolving into highly distributed, dynamic networks in order to address the climate change. This fundamental transition relies on extensive automation solutions based on communications and information technologies. Thus, it also gives rise to new attack points for malicious actors and consequently, increases the vulnerability of the electric energy system. This study presents a qualitative assessment of power grid cybersecurity through expert interviews across countries in Europe and the U.S. to gain understanding of the latest developments and trends in the cybersecurity of future electric energy systems. The horizon of the assessment is 10 years spanning until the early 2030s. Thereafter, the study identifies how and to which extent the risks identified to be most significant are understood and addressed in the latest research and industry publications aiming at identifying areas deserving specific further attention. The most significant threats based on the assessment are False Data Injection (FDI), Denial of Service (DoS) supply chain, and ransomware and malware attacks.

  • 17.
    Borisoot, Kanjanapon
    et al.
    Department of Electrical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand.
    Liemthong, Rittichai
    Business Development Engineer, Sermsang Power Corporation Public Company Limited, Bangkok 10300, Thailand.
    Srithapon, Chitchai
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elektroteknisk teori och konstruktion.
    Chatthaworn, Rongrit
    Department of Electrical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen 40002, Thailand;Center for Alternative Energy Research and Development, Khon Kaen University, Khon Kaen 40002, Thailand.
    Optimal Energy Management for Virtual Power Plant Considering Operation and Degradation Costs of Energy Storage System and Generators2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 6, s. 2862-2862Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Even though generating electricity from Renewable Energy (RE) and electrification of transportation with Electric Vehicles (EVs) can reduce climate change impacts, uncertainties of the RE and charged demand of EVs are significant challenges for energy management in power systems. To deal with this problem, this paper proposes an optimal energy management method using the Virtual Power Plant (VPP) concept for the power system considering solar PhotoVoltaics (PVs) and Electric Vehicle Charging Stations (EVCS). The Differential Evolution (DE) algorithm is applied to manage energy in the power system to minimize the operation cost of generators and degradation costs in Energy Storage Systems (ESS) and generators. The effectiveness of the proposed approach is examined and tested on the IEEE 24 bus Reliability Test System (RTS 24) using the MATPOWER tool on the MATLAB program for calculating Optimal Power Flow (OPF). In this study, two situations before and after applying the proposed method are considered. The simulation results demonstrate that a branch constraint violation occurs before using optimal energy management using the VPP concept. In order to solve this issue, the DE algorithm for optimal energy management using the VPP concept is applied by dividing the studied case into two subcases as follows. For the first subcase, two objectives consisting of the minimization of the generator operation cost and the minimization of the battery degradation cost in ESS are considered. In the second case, three objectives comprising the two mentioned objectives with the minimization of generator degradation cost are considered. The results demonstrate that branch constraint violations can be avoided by applying optimal energy management using the VPP concept. This study also suggests considering the generator degradation cost in the objective function, which can minimize the total costs by 7.06% per day compared with the total cost of the first case.

  • 18.
    Bäcklund, Katarina
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Molinari, Marco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Palm, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Building Occupants, Their Behavior and the Resulting Impact on Energy Use in Campus Buildings: A Literature Review with Focus on Smart Building Systems2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 17, s. 6104-6104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the light of global climate change and the current energy crisis, it is crucial to target sustainable energy use in all sectors. Buildings still remain one of the most energy-demanding sectors. Campus buildings and higher educational buildings are important to target due to their high and increasing energy demand. This building segment also represents a research gap, as mostly office or domestic buildings have been studied previously. In the quest for thermal comfort, a key stakeholder in building energy demand is the building occupant. It is therefore crucial to promote energy-aware behaviors. The building systems are another key factor to consider. As conventional building systems are replaced with smart building systems, the entire scenario is redrawn for how building occupants interact with the building and its systems. This study argues that behavior is evolving with the smartness of building systems. By means of a semi-systematic literature review, this study presents key findings from peer-reviewed research that deal with building occupant behavior, building systems and energy use in campus buildings. The literature review was an iterative process based on six predefined research questions. Two key results are presented: a graph of reported energy-saving potentials and a conceptual framework to evaluate building occupants impact on building energy use. Furthermore, based on the identified research gaps in the selected literature, areas for future research are proposed.

  • 19.
    Cabañas Ramos, Jaqueline
    et al.
    Institute for Automation of Complex Power Systems, RWTH Aachen University, 52074 Aachen, Germany;.
    Moritz, Marc
    Institute for Automation of Complex Power Systems, RWTH Aachen University, 52074 Aachen, Germany;.
    Klötzl, Nico
    TenneT TSO GmbH, Bayreuth, 95448, Germany.
    Nieuwenhout, Ceciel
    Groningen Centre of Energy Law and Sustainability, University of Groningen, Groningen, 9700 AB, Netherlands.
    Leon Garcia, William
    SuperGrid Institute, Villeurbanne, 69100, France.
    Jahn, Ilka
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Kolichev, Dimitar
    T&D Europe, Brussels, B1030, Belgium.
    Monti, Antonello
    Institute for Automation of Complex Power Systems, RWTH Aachen University, 52074 Aachen, Germany;.
    Getting Ready for Multi-Vendor and Multi-Terminal HVDC Technology2024Ingår i: Energies, E-ISSN 1996-1073, Vol. 17, nr 10, artikel-id 2388Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Interoperable multi-vendor High-Voltage Direct-Current (HVDC) grids are a key enabler for the integration of renewable energy (in particular offshore wind) and its transmission over longer distances to consumers. However, most HVDC systems today are single-vendor and point-to-point. Various technical and non-technical aspects need to be considered, for example, (real-time) testing, legal aspects (intellectual property and regulation), and the multi-vendor interoperability process. This paper presents findings from the READY4DC project, which is a larger and open European effort involving diverse stakeholders, including HVDC manufacturers, transmission system operators, wind developers, academia, and research institutes. It summarizes key technical recommendations, emphasizing comprehensive interaction studies and the development of a structured legal framework to facilitate the development and operation of a multi-vendor, multi-terminal HVDC grid. The READY4DC project highlights the need for increased harmonization, transparent communication among stakeholders, and future-oriented research to ensure the robustness and interoperability of interconnected grids. Collaborative efforts are key for addressing technical complexities and advancing the deployment of multi-vendor multi-terminal HVDC technology.

  • 20.
    Cannone, Carla
    et al.
    Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK; Centre for Environmental Policy, Imperial College London, London, SW7 1NE, UK.
    Hoseinpoori, Pooya
    Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
    Martindale, Leigh
    Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK; Centre for Environmental Policy, Imperial College London, London, SW7 1NE, UK.
    Tennyson, Elizabeth M.
    Centre for Global Equality, Cambridge, CB2 1SJ, UK; Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK.
    Gardumi, Francesco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystem.
    Somavilla Croxatto, Lucas
    Department of Science, Technology, Engineering and Public Policy, University College London, London, WC1E 6JA, UK.
    Pye, Steve
    UCL Energy Institute, University College London, London, WC1H 0NN, UK.
    Mulugetta, Yacob
    Department of Science, Technology, Engineering and Public Policy, University College London, London, WC1E 6JA, UK.
    Vrochidis, Ioannis
    TUM School of Engineering and Design, Technical University of Munich, Garching b. München, 85748, Germany.
    Krishnamurthy, Satheesh
    School of Engineering and Innovation, The Open University, Milton Keynes, MK7 6AA, UK.
    Niet, Taco
    School of Sustainable Energy Engineering, Simon Fraser University, Surrey, BC, V3T 0N1, Canada.
    Harrison, John
    Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK.
    Yeganyan, Rudolf
    Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK.
    Mutembei, Martin
    Strathmore Energy Research Centre (SERC), Strathmore University, Madaraka Campus, Nairobi, 00200, Kenya, Madaraka Campus.
    Hawkes, Adam
    Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
    Petrarulo, Luca
    Milan, 20124, Italy.
    Allen, Lara
    Centre for Global Equality, Cambridge, CB2 1SJ, UK; Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK.
    Blyth, Will
    Foreign, Commonwealth & Development Office, London, SW1A 2AH, UK.
    Howells, Mark
    Department of Geography and Environment, Loughborough University, Loughborough, LE11 3TU, UK; Centre for Environmental Policy, Imperial College London, London, SW7 1NE, UK.
    Addressing Challenges in Long-Term Strategic Energy Planning in LMICs: Learning Pathways in an Energy Planning Ecosystem2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 21, artikel-id 7267Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an innovative approach to addressing critical global challenges in long-term energy planning for low- and middle-income countries (LMICs). The paper proposes and tests an international enabling environment, a delivery ecosystem, and a community of practice. These components are integrated into workflows that yield four self-sustaining capacity-development outcomes. Planning long-term energy strategies in LMICs is particularly challenging due to limited national agency and poor international coordination. While outsourcing energy planning to foreign experts may appear to be a viable solution, it can lead to a reduction in government agency (the ability of a government to make its own informed analysis and decisions). Additionally, studies commissioned by external experts may have conflicting terms of reference, and a lack of familiarity with local conditions can result in misrepresentations of on-the-ground realities. It is argued here that enhancing national agency and analytical capacity can improve coordination and lead to more robust planning across line ministries and technical assistance (TA) providers. Moreover, the prevailing consulting model hampers the release and accessibility of underlying analytics, making it difficult to retrieve, reuse, and reconstruct consultant outputs. The absence of interoperability among outputs from various consultants hinders the ability to combine and audit the insights they provide. To overcome these challenges, five strategic principles for energy planning in LMICs have been introduced and developed in collaboration with 21 international and research organizations, including the AfDB, IEA, IRENA, IAEA, UNDP, UNECA, the World Bank, and WRI. These principles prioritize national ownership, coherence and inclusivity, capacity, robustness, transparency and accessibility. In this enabling environment, a unique delivery ecosystem consisting of knowledge products and activities is established. The paper focuses on two key knowledge products as examples of this ecosystem: the open-source energy modeling system (OSeMOSYS) and the power system flexibility tool (IRENA FlexTool). These ecosystem elements are designed to meet user-friendliness, retrievability, reusability, reconstructability, repeatability, interoperability, and audibility (U4RIA) goals. To ensure the sustainability of this ecosystem, OpTIMUS is introduced—a community of practice dedicated to maintaining, supporting, expanding, and nurturing the elements within the ecosystem. Among other ecosystem elements, training and research initiatives are introduced, namely the Energy Modelling Platform for Africa, Latin America and the Caribbean, and Asia-Pacific as well as the ICTP Joint Summer School on Modelling Tools for Sustainable Development. Once deployed via workflows, the preliminary outcomes of these capacity-development learning pathways show promise. Further investigation is necessary to evaluate their long-term impacts, scalability, replication, and deployment costs.

  • 21. Cantillo-Luna, Sergio
    et al.
    Moreno-Chuquen, Ricardo
    Chamorro Vera, Harold R.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Riquelme-Dominguez, Jose Miguel
    Gonzalez-Longatt, Francisco
    Locational Marginal Price Forecasting Using SVR-Based Multi-Output Regression in Electricity Markets2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 1, artikel-id 293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electricity markets provide valuable data for regulators, operators, and investors. The use of machine learning methods for electricity market data could provide new insights about the market, and this information could be used for decision-making. This paper proposes a tool based on multi-output regression method using support vector machines (SVR) for LMP forecasting. The input corresponds to the active power load of each bus, in this case obtained through Monte Carlo simulations, in order to forecast LMPs. The LMPs provide market signals for investors and regulators. The results showed the high performance of the proposed model, since the average prediction error for fitting and testing datasets of the proposed method on the dataset was less than 1%. This provides insights into the application of machine learning method for electricity markets given the context of uncertainty and volatility for either real-time and ahead markets.

  • 22. Cantillo-Luna, Sergio
    et al.
    Moreno-Chuquen, Ricardo
    Gonzalez-Longatt, Francisco
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    A Type-2 Fuzzy Controller to Enable the EFR Service from a Battery Energy Storage System2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increased use of distributed energy resources, especially electrical energy storage systems (EESS), has led to greater flexibility and complexity in power grids, which has led to new challenges in the operation of these systems, with particular emphasis on frequency regulation. To this end, the transmission system operator in Great Britain has designed a control scheme known as Enhanced Frequency Response (EFR) that is especially attractive for its implementation in EESS. This paper proposes a Type-2 fuzzy control system that enables the provision of EFR service from a battery energy storage system in order to improve the state-of-charge (SoC) management while providing EFR service from operating scenarios during working and off-duty days. The performance of the proposed controller is compared with a conventional FLC and PID controllers with similar features. The results showed that in all scenarios, but especially under large frequency deviations, the proposed controller presents a better SoC management in comparison without neglecting the EFR service provision.

  • 23.
    Castellani, Francesco
    et al.
    Univ Perugia, Dept Engn, Via G Durand 93, I-06125 Perugia, Italy..
    Eltayesh, Abdelgalil
    Benha Univ, Benha Fac Engn, Mech Engn Dept, Banha 13512, Egypt..
    Becchetti, Matteo
    Univ Perugia, Dept Engn, Via G Durand 93, I-06125 Perugia, Italy..
    Segalini, Antonio
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik.
    Aerodynamic Analysis of a Wind-Turbine Rotor Affected by Pitch Unbalance2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 3, artikel-id 745Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aerodynamics of a rotor with pitch imbalance has been investigated experimentally and numerically in the present work. The comparison of mean velocity and turbulence intensity in the balanced and unbalanced cases indicated that a pitch imbalance modifies both the mean velocity and the turbulent activity; the latter is weakly increased by the imbalance. Spectral analysis indicated that the dynamics of the wake is also affected by the pitch imbalance since the tip vortices loose strength and disorganise more quickly than in the balanced case. The pitch imbalance has, however, a detrimental effect on the power coefficient and it affects the thrust coefficient as well. Only the blade affected by the imbalance shows significant modifications of the applied load, while the other blades operate with the same loading conditions.

  • 24.
    Chiche, Ariel
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Stenius, Ivan
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Farkostteknik och Solidmekanik.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Including Heat Balance When Designing the Energy System of Fuel Cell-Powered AUVs2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 16, s. 4920-4920, artikel-id 4920Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fuel cell-powered Autonomous Underwater Vehicles (AUVs) represent a growing area of research as fuel cells can increase their endurance. Fuel cells consume hydrogen and oxygen to generate electricity. Typically, the fuel cell generates as much heat as electrical energy, and heat management becomes a crucial parameter when designing AUVs. For underwater applications, there is a need to store both gases and several types of storage units with different characteristics exist which have impacts on the energy density and heat behavior. This study aims at including the heat properties of the storage units in the design process of fuel cell-powered AUVs. A heat balance over the energy system of an AUV is calculated for each combination of hydrogen and oxygen storage units. In addition, a multi-criteria decision-making analysis is conducted, considering the calculated total heat, the specific energy, the energy density and the volumetric mass of each combination of storage units as criteria, enabling a comparison and ranking them using two objective criteria weighting methods. Results show that the fuel cell is the major contributor to the heat balance, and that the combinations of liquid oxygen with liquid or compressed hydrogen can be relevant and suitable for underwater applications. 

  • 25.
    Chronis, Alexandros-Georgios
    et al.
    Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens 15780, Greece..
    Palaiogiannis, Foivos
    Collect Energy Cooperat, Energy Community, Athens 11631, Greece..
    Kouveliotis Lysikatos, Iasonas
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Kotsampopoulos, Panos
    Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens 15780, Greece..
    Hatziargyriou, Nikos
    Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens 15780, Greece..
    Photovoltaics Enabling Sustainable Energy Communities: Technological Drivers and Emerging Markets2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 7, artikel-id 1862Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the economic benefits of an energy community investing in small-scale photovoltaics (PVs) when local energy trading is operated amongst the community members. The motivation stems from the open research question on whether a community-operated local energy market can enhance the investment feasibility of behind-the-meter small-scale PVs installed by energy community members. Firstly, a review of the models, mechanisms and concepts required for framing the relevant concepts is conducted, while a clarification of nuances at important terms is attempted. Next, a tool for the investigation of the economic benefits of operating a local energy market in the context of an energy community is developed. We design the local energy market using state-of-the-art formulations, modified according to the requirements of the case study. The model is applied to an energy community that is currently under formation in a Greek municipality. From the various simulations that were conducted, a series of generalizable conclusions are extracted.

  • 26. Cortes-Caicedo, Brandon
    et al.
    Avellaneda-Gomez, Laura Sofi­a
    Montoya, Oscar Danilo
    Alvarado-Barrios, Lazaro
    Chamorro Vera, Harold Rene
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik.
    Application of the Vortex Search Algorithm to the Phase-Balancing Problem in Distribution Systems2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article discusses the problem of minimizing power loss in unbalanced distribution systems through phase-balancing. This problem is represented by a mixed-integer nonlinearprogramming mathematical model, which is solved by applying a discretely encoded Vortex Search Algorithm (DVSA). The numerical results of simulations performed in IEEE 8-, 25-, and 37-node test systems demonstrate the applicability of the proposed methodology when compared with the classical Cuh & Beasley genetic algorithm. In addition, the computation times required by the algorithm to find the optimal solution are in the order of seconds, which makes the proposed DVSA a robust, reliable, and efficient tool. All computational implementations have been developed in the MATLAB® programming environment, and all the results have been evaluated in DigSILENT© software to verify the effectiveness and the proposed three-phase unbalanced power-flow method.

  • 27.
    Cuvila, Carlos Alberto
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Kantarelis, Efthymios
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    Yang, Weihong
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Energi- och ugnsteknik.
    The Impact of a Mild Sub-Critical Hydrothermal Carbonization of Pretreatment on Umbila Wood: A Mass and Energy Balance Perspective2015Ingår i: Energies, E-ISSN 1996-1073, Vol. 8, nr 3, s. 2165-2175Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  • 28.
    Czajkowski, Adrian
    et al.
    Silesian Tech Univ, Doctoral Sch, Akad 2A, PL-44100 Gliwice, Poland.;Silesian Tech Univ, Fac Energy & Environm Engn, Dept Power Engn & Turbomachinery, Konarskiego 18, PL-44100 Gliwice, Poland.;Miscea Pl Engn Sp Zoo, Zimnej Wody 9, PL-44100 Gliwice, Poland..
    Wajda, Agata
    Inst Energy & Fuel Proc Technol, PL-41803 Zabrze, Poland..
    Poranek, Nikolina
    Silesian Tech Univ, Doctoral Sch, Akad 2A, PL-44100 Gliwice, Poland.;Silesian Tech Univ, Fac Energy & Environm Engn, Dept Technol & Installat Waste Management, Konarskiego 18, PL-44100 Gliwice, Poland.;Silesian Tech Univ, Fac Civil Engn, Dept Bldg Engn & Bldg Phys, Akad 5, PL-44100 Gliwice, Poland..
    Bhadoria, Shubhangi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Remiorz, Leszek
    Silesian Tech Univ, Fac Energy & Environm Engn, Dept Power Engn & Turbomachinery, Konarskiego 18, PL-44100 Gliwice, Poland..
    Prediction of the Market of End-of-Life Photovoltaic Panels in the Context of Common EU Management System2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 1, s. 284-, artikel-id 284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A significant development of the photovoltaic market in the European Union has been observed recently. This is mainly due to the adopted climate policy and the development of photovoltaic technology, resulting in increased availability for consumers at lower prices. In the long run, increased installed PV capacity is associated with an increased amount of photovoltaic waste generated at the end of life. Since this waste belongs to the group of WEEE (waste electrical and electronic equipment) waste, it is subjected to high recovery levels. Existing installations for the highly efficient recycling of PV panels are just proofs of concept. However, the situation will change in the near future, and it will be necessary to implement a full-scale waste management system dedicated to PV waste. The paper estimates mass streams of photovoltaic waste generated by 2050 in individual EU countries. Consequently, the characteristics of the European market of waste PV panels are considered together with the demand of individual Member States for installations. The estimation enables the fulfillment of the Directive on WEEE recovery rates.

  • 29.
    Dimitropoulos, Dimitrios
    et al.
    Aalborg Univ, AAU Energy, DK-9220 Aalborg, Denmark..
    Bakhshizadeh, Mohammad Kazem
    Orsted Wind Power AS, DK-2820 Gentofte, Denmark..
    Kocewiak, Lukasz
    Orsted Wind Power AS, DK-2820 Gentofte, Denmark..
    Wang, Xiongfei
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik. Aalborg Univ, AAU Energy, DK-9220 Aalborg, Denmark.
    Blaabjerg, Frede
    Aalborg Univ, AAU Energy, DK-9220 Aalborg, Denmark..
    Impact of Synchronous Condensers' Ratings on Mitigating Subsynchronous Oscillations in Wind Farms2024Ingår i: Energies, E-ISSN 1996-1073, Vol. 17, nr 7, artikel-id 1730Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Subsynchronous oscillations have occurred in wind farms due to the high penetration of converter-based technology in power systems and may potentially lead to grid instability. As an effective solution, synchronous condensers, with their ability to control voltage and inject reactive power in the power system, are increasingly being adopted, as they can lead to the mitigation of such oscillations in weak grid conditions. However, the impact of synchronous condensers' power ratings on system stability is a topic that requires further investigation. In fact, an improper selection of a synchronous condenser's rating will not extinguish existing subsynchronous oscillations and may even cause the emergence of new oscillatory phenomena. This paper presents a novel examination of the impact that the synchronous condenser's power rating has on the small-signal stability of a wind farm with existing subsynchronous oscillations while being connected to a weak grid. The wind farm's model is developed using state-space modeling, centering on grid interconnection and incorporating the state-space submodel of a synchronous condenser to show its impact on subsynchronous oscillation mitigation. The stability analysis determines the optimal synchronous condenser's power ratings for suppressing these oscillations in the wind farm model. The findings are corroborated through time domain simulations and fast-Fourier transformation (FFT) analysis, which further validate the stability effects of a synchronous condenser's rating.

  • 30.
    Ding, Saiman
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Kemisk apparatteknik.
    Kantarelis, Efthymios
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Processteknologi.
    Engvall, Klas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Processteknologi.
    Effects of Porous Structure Development and Ash on the Steam Gasification Reactivity of Biochar Residues from a Commercial Gasifier at Different Temperatures2020Ingår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 18, artikel-id 5004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study aims at investigating the effects of porous structure development and ash content on the observed reactivity during steam gasification of biochar residues from a commercial gasifier. The experiments were conducted at a temperature range of 700 to 800 °C using biochar, derived from entrained flow gasification of biomass, under isothermal conditions using a thermogravimetric analyzer. The pore size distribution, surface area and morphology of char samples were determined by N2 physiosorption and scanning electron microscopy (SEM). The results showed that the gasification temperature does not affect the porous structure development considerably. The total surface area of char exhibits a threefold increase, while the total pore volume increase ranges between 2.0 and 5.3 times, at all temperatures. Both properties are directly proportional to the observed reactivity, especially at conversions up to 70%. Catalytic effects of the mineral matter of the char (mainly potassium) become predominant at the later stages of conversion (conversion greater than 70%).

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  • 31.
    Dires, Firehiwot Girma
    et al.
    School of Electrical and Computer Engineering, Addis Ababa Institute of Technology, 385, Addis Ababa, Ethiopi.
    Amelin, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    Bekele, Getachew
    School of Electrical and Computer Engineering, Addis Ababa Institute of Technology, 385, Addis Ababa, Ethiopia.
    Long-Term Hydropower Planning for Ethiopia: A Rolling Horizon Stochastic Programming Approach with Uncertain Inflow2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 21, artikel-id 7399Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    All long-term hydropower planning problems require a forecast of the inflow during the planning period. However, it is challenging to accurately forecast inflows for a year or more. Therefore, it is common to use stochastic models considering the uncertainties of the inflow. This paper compares deterministic and stochastic models in a weekly rolling horizon framework considering inflow uncertainty. The stochastic model is tested in both a risk-neutral and a risk-averse version. The rolling horizon framework helps make periodic decisions and update the information in each rolling week, which minimizes the errors in prolonged forecasts. The models aim to utilize the water stored in the rainy season throughout the year with minimum load shedding while storing as much water as possible at the end of the planning horizon. The Conditional Value at Risk ((Formula presented.)) risk measure is used to develop the risk-averse stochastic model. Three different risk measures are investigated to choose the risk measure that yields the best outcome in the risk-averse problem, and the two best measures are compared to a deterministic and risk-neutral model in a weekly rolling horizon framework. The results show that the risk-neutral and best risk-averse models perform almost equally and are better than the deterministic model. Hence, using a stochastic model would be an improvement to the actual planning performed in the Ethiopian and other African countries’ power systems.

  • 32.
    Dreier, Dennis
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Howells, Mark I.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    OSeMOSYS-PuLP: A Stochastic Modeling Framework for Long-Term Energy Systems Modeling2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 7, artikel-id 1382Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent open-data movements give access to large datasets derived from real-world observations. This data can be utilized to enhance energy systems modeling in terms of heterogeneity, confidence, and transparency. Furthermore, it allows to shift away from the common practice of considering average values towards probability distributions. In turn, heterogeneity and randomness of the real-world can be captured that are usually found in large samples of real-world data. This paper presents a methodological framework for an empirical deterministic-stochastic modeling approach to utilize large real-world datasets in long-term energy systems modeling. A new software systemOSeMOSYS-PuLPwas developed and is available now.It adds the feature of Monte Carlo simulations to the existing open-source energy modeling system (the OSeMOSYS modeling framework). An application example is given, in which the initial application example of OSeMOSYS is used and modified to include real-world operation data from a public bus transport system.

  • 33. Du, Mian
    et al.
    Yi, Jun
    Mazidi, Peyman
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Cheng, Lin
    Guo, Jianbo
    A Parameter Selection Method for Wind Turbine Health Management through SCADA Data2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 2, artikel-id 253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wind turbine anomaly or failure detection using machine learning techniques through supervisory control and data acquisition (SCADA) system is drawing wide attention from academic and industry While parameter selection is important for modelling a wind turbine's condition, only a few papers have been published focusing on this issue and in those papers interconnections among sub-components in a wind turbine are used to address this problem. However, merely the interconnections for decision making sometimes is too general to provide a parameter list considering the differences of each SCADA dataset. In this paper, a method is proposed to provide more detailed suggestions on parameter selection based on mutual information. First, the copula is proven to be capable of simplifying the estimation of mutual information. Then an empirical copula-based mutual information estimation method (ECMI) is introduced for application. After that, a real SCADA dataset is adopted to test the method, and the results show the effectiveness of the ECMI in providing parameter selection suggestions when physical knowledge is not accurate enough.

  • 34.
    Effatpisheh, Aref
    et al.
    Shiraz Univ Technol, Dept Mech & Aerosp Engn, Shiraz 71557, Iran..
    Vadiee, Amir
    Mälardalen Univ, Sch Business Soc & Engn, Div Civil Engn & Energy Syst, S-72123 Västerås, Sweden..
    A Monfared, Behzad
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Mathematical Modelling of Active Magnetic Regenerator Refrigeration System for Design Considerations2020Ingår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 23, artikel-id 6301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A magnetic refrigeration system has the potential to alternate the compression system with respect to environmental compatibility. Refrigeration systems currently operate on the basis of the expansion and compression processes, while active magnetic refrigeration systems operate based on the magnetocaloric effect. In this study, a single layer of Gd was used as the magnetocaloric material for six-packed-sphere regenerators. A one-dimensional numerical model was utilized to simulate the magnetic refrigeration system and determine the optimum parameters. The optimum mass flow rate and maximum cooling capacity at frequency of 4 Hz are 3 L.min(-1) and 580 W, respectively. The results show that the maximum pressure drop increased by 1400 W at a frequency of 4 Hz and mass flow rate of 5 L.min(-1). In this study, we consider the refrigeration system in terms of the design considerations, conduct a parametric study, and determine the effect of various parameters on the performance of the system.

  • 35.
    El Gohary, Fouad
    et al.
    Uppsala Univ, Dept Civil &amp; Ind Engn, Box 169, S-75104 Uppsala, Sweden..
    Nyström, Sofie
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Reitsma, Lizette
    Malmö Univ, Dept Culture &amp; Soc, S-20506 Malmö, Sweden..
    Bartusch, Cajsa
    Uppsala Univ, Dept Civil &amp; Ind Engn, Box 169, S-75104 Uppsala, Sweden..
    Identifying Challenges in Engaging Users to Increase Self-Consumption of Electricity in Microgrids2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 5, artikel-id 1257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A microgrid's self-consumption rate reflects its ability to retain its own energy and decrease its reliance on the synchronous grid. This paper investigates the empirical case of a microgrid equipped with photovoltaic (PV) panels and identifies challenges in engaging the microgrid's users to increase their self-consumption. Accordingly, we explored both the physical and social dimensions of the microgrid. The former involved mapping the electricity consumption and production through an exploratory data analysis, and evaluating the associated price signals, while the latter involved the use of design interventions to explore users' perceptions of the system. We highlight the problem of price signal impedance, the need for cost reflective pricing and the challenge in designing and extending internal price models in settings with various actors. We address the limitations of price signals, alongside alternative unidimensional signals, and emphasize the need for an integrated approach to a user engagement strategy as well as the challenges that this approach entails. Our results shed light on the complexity of energy communities such as microgrids, and why their implementation can introduce multidimensional challenges that demand cross-disciplinary approaches.

  • 36. Eriksson, Ola
    et al.
    Finnveden, Göran
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Miljöstrategisk analys (fms).
    Energy Recovery from Waste Incineration: The Importance of Technology Data and System Boundaries on CO2 Emissions2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 4, artikel-id 539Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previous studies on waste incineration as part of the energy system show that waste management and energy supply are highly dependent on each other, and that the preconditions for the energy system setup affects the avoided emissions and thereby even sometimes the total outcome of an environmental assessment. However, it has not been previously shown explicitly which key parameters are most crucial, how much each parameter affects results and conclusions and how different aspects depend on each other. The interconnection between waste incineration and the energy system is elaborated by testing parameters potentially crucial to the result: design of the incineration plant, avoided energy generation, degree of efficiency, electricity efficiency in combined heat and power plants (CHP), avoided fuel, emission level of the avoided electricity generation and avoided waste management. CO2 emissions have been calculated for incineration of 1 kWh mixed combustible waste. The results indicate that one of the most important factors is the electricity efficiency in CHP plants in combination with the emission level of the avoided electricity generation. A novel aspect of this study is the plant by plant comparison showing how different electricity efficiencies associated with different types of fuels and plants influence results. Since waste incineration typically have lower power to fuel ratios, this has implications for further analyses of waste incineration compared to other waste management practises and heat and power production technologies. New incineration capacity should substitute mixed landfill disposal and recovered energy should replace energy from inefficient high polluting plants. Electricity generation must not be lost, as it has to be compensated for by electricity production affecting the overall results.

  • 37.
    Faure, Xavier
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Johansson, Tim
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Pasichnyi, Oleksii
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    The Impact of Detail, Shadowing and Thermal Zoning Levels on Urban Building Energy Modelling (UBEM) on a District Scale2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 4, s. 1525-, artikel-id 1525Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New modelling tools are required to accelerate the decarbonisation of the building sector. Urban building energy modelling (UBEM) has recently emerged as an attractive paradigm for analysing building energy performance at district and urban scales. The balance between the fidelity and accuracy of created UBEMs is known to be the cornerstone of the model's applicability. This study aimed to analyse the impact of traditionally implicit modeller choices that can greatly affect the overall UBEM performance, namely, (1) the level of detail (LoD) of the buildings' geometry; (2) thermal zoning; and (3) the surrounding shadowing environment. The analysis was conducted for two urban areas in Stockholm (Sweden) using MUBES-the newly developed UBEM. It is a bottom-up physics-based open-source tool based on Python and EnergyPlus, allowing for calibration and co-simulation. At the building scale, significant impact was detected for all three factors. At the district scale, smaller effects (<2%) were observed for the level of detail and thermal zoning. However, up to 10% difference may be due to the surrounding shadowing environment, so it is recommended that this is considered when using UBEMs even for district scale analyses. Hence, assumptions embedded in UBEMs and the scale of analysis make a difference.

  • 38.
    Frodeson, Stefan
    et al.
    Karlstad Univ, Dept Engn & Chem Sci, Environm & Energy Syst, SE-65188 Karlstad, Sweden..
    Anukam, Anthony Ike
    Karlstad Univ, Dept Engn & Chem Sci, Environm & Energy Syst, SE-65188 Karlstad, Sweden..
    Berghel, Jonas
    Karlstad Univ, Dept Engn & Chem Sci, Environm & Energy Syst, SE-65188 Karlstad, Sweden..
    Stahl, Magnus
    Karlstad Univ, Dept Engn & Chem Sci, Environm & Energy Syst, SE-65188 Karlstad, Sweden..
    Nilsson, Rasika Lasanthi Kudahettige
    Karlstad Univ, Dept Engn & Chem Sci, Environm & Energy Syst, SE-65188 Karlstad, Sweden..
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Aladejana, Elizabeth Bosede
    Univ Ft Hare, Fac Sci & Agr, Electron Microscopy Unit, Cent Analyt Lab, ZA-5700 Alice, South Africa..
    Densification of Wood-Influence on Mechanical and Chemical Properties when 11 Naturally Occurring Substances in Wood Are Mixed with Beech and Pine2021Ingår i: Energies, E-ISSN 1996-1073, Vol. 14, nr 18, artikel-id 5895Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The need to increase the use of renewable biomasses for energy supply, such as fuel pellets is significant. However, different types of biomasses have different mechanical properties to be pelletized, which entails a limitation in available raw materials for pellet producers. Within this study eleven different pure substances from biomasses were separately mixed with European beech and Scots pine, to identify its impact on the densification process. Beech and pine pellets were used as control materials against their corresponding pellets mixed with substances representing: cellulose, hemicelluloses, other polysaccharides, lignin, protein, and extractives. The mechanical properties were investigated as well as FT-IR and SEM analyses on the pellets. The results showed that the addition of the substances xylan and galactan created the hardest pellets for both pine and beech and that adding extractives to wood affects pine more than beech in relation to hardness. The FT-IR data could not provide clear explanations as to the variation in hardness and springback behavior through the identification of major functional groups in each pellet. It can be concluded that biomass residues rich in xylan and galactan increase pellet quality in terms of strength and durability without affecting the production process.

  • 39. Gantasala, Sudhakar
    et al.
    Tabatabaei, Narges
    Cervantes, Michel
    Aidanpää, Jan-Olov
    Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wind turbines installed in cold-climate regions are prone to the risks of ice accumulation which affects their aeroelastic behavior. The studies carried out on this topic so far considered icing in a few sections of the blade, mostly located in the outer part of the blade, and their influence on the loads and power production of the turbine are only analyzed. The knowledge about the influence of icing in different locations of the blade and asymmetrical icing of the blades on loads, power, and vibration behavior of the turbine is still not matured. To improve this knowledge, multiple simulation cases are needed to run with different ice accumulations on the blade considering structural and aerodynamic property changes due to ice. Such simulations can be easily run by automating the ice shape creation on aerofoil sections and two-dimensional (2-D) Computational Fluid Dynamics (CFD) analysis of those sections. The current work proposes such methodology and it is illustrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The influence of symmetrical icing in different locations of the blade and asymmetrical icing of the blade assembly is analyzed on the turbine&rsquo;s dynamic behavior using the aeroelastic computer-aided engineering tool FAST. The outer third of the blade produces about 50% of the turbine&rsquo;s total power and severe icing in this part of the blade reduces power output and aeroelastic damping of the blade&rsquo;s flapwise vibration modes. The increase in blade mass due to ice reduces its natural frequencies which can be extracted from the vibration responses of the turbine operating under turbulent wind conditions. Symmetrical icing of the blades reduces loads acting on the turbine components, whereas asymmetrical icing of the blades induces loads and vibrations in the tower, hub, and nacelle assembly at a frequency synchronous to rotational speed of the turbine.

  • 40.
    García Veloso, Cesar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS). Tech Univ Catalonia, Barcelona Sch Ind Engn, Barcelona 08028, Spain..
    Rauma, Kalle
    TU Dortmund Univ, Inst Energy Syst Energy Efficiency & Energy Econ, D-44227 Dortmund, Germany..
    Fernandez, Julian
    Univ Victoria, Inst Integrated Energy Syst, Victoria, BC V8W 2Y2, Canada..
    Rehtanz, Christian
    TU Dortmund Univ, Inst Energy Syst Energy Efficiency & Energy Econ, D-44227 Dortmund, Germany..
    Real-Time Control of Plug-in Electric Vehicles for Congestion Management of Radial LV Networks: A Comparison of Implementations2020Ingår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 16, artikel-id 4227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The global proliferation of plug-in electric vehicles (PEVs) poses a major challenge for current and future distribution systems. If uncoordinated, their charging process may cause congestion on both network transformers and feeders, resulting in overheating, deterioration, protection triggering and eventual risk of failure, seriously compromising the stability and reliability of the grid. To mitigate such impacts and increase their hosting capacity in radial distribution systems, the present study compares the levels of effectiveness and performances of three alternative centralized thermal management formulations for a real-time agent-based charge control algorithm that aims to minimize the total impact upon car owners. A linear formulation and a convex formulation of the optimization problem are presented and solved respectively by means of integer linear programming and a genetic algorithm. The obtained results are then compared, in terms of their total impact on the end-users and overall performance, with those of the current heuristic implementation of the algorithm. All implementations were tested using a simulation environment considering multiple vehicle penetration and base load levels, and equipment modeled after commercially available charging stations and vehicles. Results show how faster resolution times are achieved by the heuristic implementation, but no significant differences between formulations exist in terms of network management and end-user impact. Every vehicle reached its maximum charge level while all thermal impacts were mitigated for all considered scenarios. The most demanding scenario showcased over a 30% reduction in the peak load for all thermal variants.

  • 41.
    Gardumi, Francesco
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys.
    Welsch, Manuel
    IAEA, Vienna Int Ctr, Planning & Econ Studies Sect, A-1400 Vienna, Austria..
    Howells, Mark I.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys.
    Colombo, Emanuela
    Politecn Milan, Sustainable Energy Syst Anal & Modelling, Dept Energy, Via Lambruschini 4c, I-20156 Milan, Italy..
    Representation of Balancing Options for Variable Renewables in Long-Term Energy System Models: An Application to OSeMOSYS2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 12, artikel-id 2366Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growing complexity and the many challenges related to fast-changing and highly de-carbonised electricity systems require reliable and robust open source energy modelling frameworks. Their reliability may be tested on a series of well-posed benchmarks that can be used and shared by the modelling community. This paper describes and integrates stand-alone, independent modules to compute the costs and benefits of flexible generation options in the open source energy investment modelling framework OSeMOSYS. The modules are applied to a case study that may work as a benchmark. The whole documentation of the modules and the test case study are retrievable, reproducible, reusable, interoperable, and auditable. They create a case to help establish a FAIR-compliant, user-friendly, and low-threshold model and data standards in modelling practices. As is well known, one of the options for balancing high shares of variable renewables is flexible power generation by dispatchable units. The associated costs need to be considered for short-term operational analyses and for long-term investment plans. The added modules contribute to extending the modelling capacity by introducing (a) costs of ramping, (b) non-linear decrease of efficiency at partial load operation, and the cost minimisation objective function of OSeMOSYS. From application to the test case study, two main insights are drawn: costs of ramping and decreased partial load efficiency may influence the competitiveness of generation technologies in the provision of reserve capacity; and refurbishment of existing units may represent attractive investment options for increasing flexibility. Both effects are also seen in the long-term and may impact infrastructure investment decisions to meet decarbonisation targets. These effects would not be captured without the introduction of the modules.

  • 42. Garrido-Arevalo, Vi­ctor M.
    et al.
    Gil-Gonzalez, Walter
    Montoya, Oscar Danilo
    Chamorro, Harold R.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Mi­rez, Jorge
    Efficient Allocation and Sizing the PV-STATCOMs in Electrical Distribution Grids Using Mixed-Integer Convex Approximation2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photovoltaic (PV) systems are a clean energy source that allows for power generation integration into electrical networks without destructive environmental effects. PV systems are usually integrated into electrical networks only to provide active power during the day, without taking full advantage of power electronics devices, which can compensate for the reactive power at any moment during their operation. These systems can also generate dynamic reactive power by means of voltage source converters, which are called PV-STATCOM devices. This paper presents a convex formulation for the optimal integration (placement and sizing) of PV-STATCOM devices in electrical distribution systems. The proposed model considers reducing the costs of the annual energy losses and installing PV-STATCOM devices. A convex formulation was obtained to transform the hyperbolic relation between the products of the voltage into a second-order constraint via relaxation. Two simulation cases in the two IEEE test systems (33- and 69-node) with radial and meshed topologies were implemented to demonstrate the effectiveness of the proposed mixed-integer convex model. The results show that PV-STATCOM devices reduce the annual cost of energy losses of electrical networks in a more significant proportion than PV systems alone.

  • 43.
    Ghadamgahi, Mersedeh
    et al.
    KTH, Skolan för industriell teknik och management (ITM). Ovako Sweden AB, Sweden.
    Olund, Patrik
    Andersson, Nils A. I.
    KTH, Skolan för industriell teknik och management (ITM).
    Jonsson, Pär
    KTH, Skolan för industriell teknik och management (ITM).
    Numerical Study on the Effect of Lambda Value (Oxygen/Fuel Ratio) on Temperature Distribution and Efficiency of a Flameless Oxyfuel Combustion System2017Ingår i: Energies, E-ISSN 1996-1073, Vol. 10, nr 3, artikel-id 338Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The flameless oxyfuel combustion technology has been proven to be a promising new method to reduce the fuel consumption and pollutants in industrial applications. Although this technology is widely used in industrial furnaces, a lack of understanding exists about the effect of the controlling parameters on the final operational conditions is tangible. In this study, a validated computational fluid dynamics (CFD) model is used to simulate six cases of flameless oxyfuel combustion burners with different lambda values (ratio of oxygen/fuel mass flow rates). The CFD model uses the steady laminar flamelet model (SLFM) to solve the probability density function (PDF) for combustion, the discreet ordinates (DO) radiation model with the weighted sum of the gray gases model (WSGGM) to solve radiation, and the realizable k-epsilon to model the turbulence. It is seen that an increased oxygen injection velocity due to an increased lambda value increases the exhaust losses, but produces a larger volumetric flame. This leads to a more uniform temperature distribution. The total temperature difference in a case with a value of 1.02 is reported to be 272 (14.9%), while the amount for a case with a value of 1.2 is 67 (4.7%). This effect is further explained by introducing a new definition value for the furnace efficiency that includes both the thermal and production losses.

  • 44.
    Ghaem Sigarchian, Sara
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Design Optimization of a Complex PolygenerationSystem for a Hospital2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 1071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Small-scale decentralized polygeneration systems have several energetic, economic and environmental benefits. However, using multiple energy sources and providing multiple energy services can lead to complicated studies which require advanced optimization techniques for determining optimal solutions. Furthermore, several parameters can influence the design and performance of a polygeneration system. In this study, the effects of heat load, renewable generation and storage units on the optimal design and performance of a polygeneration system for a hypothetical hospital located in northern Italy are investigated. The polygeneration system shows higher performance compared to the reference system, which is based on the separate generation of heat and power. It reduces fuel consumption by 14–32%, CO2 emissions by 10–29% and annualized total cost by 7–19%, for various studied scenarios. The avoided fuel and electricity purchase of the polygeneration system has a positive impact on the economy. This, together with the environmental and energetic benefits if the renewable generation and use of storage devices, indicate the viability and competitiveness of the system.

  • 45.
    Ghaem Sigarchian, Sara
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Malmquist, Anders
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Design Optimization of a Complex Polygeneration System for a Hospital2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 5, artikel-id 1071Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Small-scale decentralized polygeneration systems have several energetic, economic and environmental benefits. However, using multiple energy sources and providing multiple energy services can lead to complicated studies which require advanced optimization techniques for determining optimal solutions. Furthermore, several parameters can influence the design and performance of a polygeneration system. In this study, the effects of heat load, renewable generation and storage units on the optimal design and performance of a polygeneration system for a hypothetical hospital located in northern Italy are investigated. The polygeneration system shows higher performance compared to the reference system, which is based on the separate generation of heat and power. It reduces fuel consumption by 14-32%, CO2 emissions by 10-29% and annualized total cost by 7-19%, for various studied scenarios. The avoided fuel and electricity purchase of the polygeneration system has a positive impact on the economy. This, together with the environmental and energetic benefits if the renewable generation and use of storage devices, indicate the viability and competitiveness of the system.

  • 46.
    Ghaem Sigarchian, Sara
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Malmquist, Anders
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Design optimization of a small-scale polygeneration energy system in different climate zones in Iran2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 5, artikel-id 1115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Design and performance of polygeneration energy systems are highly influenced by several variables, including the climate zone, which can affect the load profile as well as the availability of renewable energy sources. To investigate the effects, in this study, the design of a polygeneration system for identical residential buildings that are located in three different climate zones in Iran has been investigated. To perform the study, a model has previously developed by the author is used. The performance of the polygeneration system in terms of energy, economy and environment were compared to each other. The results show significant energetic and environmental benefits of the implementation of polygeneration systems in Iran, especially in the building that is located in a hot climate, with a high cooling demand and a low heating demand. Optimal polygeneration system for an identical building has achieved a 27% carbon dioxide emission reduction in the cold climate, while this value is around 41% in the hot climate. However, when considering the price of electricity and gas in the current energy market in Iran, none of the systems are feasible and financial support mechanisms or other incentives are required to promote the application of decentralized polygeneration energy systems.

  • 47.
    Gitau, James K.
    et al.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Sundberg, Cecilia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Mendum, Ruth
    Penn State Univ, Off Int Programs, Coll Agr Sci, 106 Agr Adm Bldg, University Pk, PA 16802 USA..
    Mutune, Jane
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya..
    Njenga, Mary
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Use of Biochar-Producing Gasifier Cookstove Improves Energy Use Efficiency and Indoor Air Quality in Rural Households2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 22, artikel-id 4285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomass fuels dominate the household energy mix in sub-Saharan Africa. Much of it is used inefficiently in poorly ventilated kitchens resulting in indoor air pollution and consumption of large amounts of wood fuel. Micro-gasification cookstoves can improve fuel use efficiency and reduce indoor air pollution while producing char as a by-product. This study monitored real-time concentrations of carbon monoxide (CO), carbon dioxide (CO2) and fine particulate matter (PM2.5), and amount of firewood used when households were cooking dinner. Twenty-five households used the gasifier cookstove to cook and five repeated the same test with three-stone open fire on a different date. With the gasifier, the average corresponding dinner time CO, CO2, and PM2.5 concentrations were reduced by 57%, 41%, and 79% respectively compared to three-stone open fire. The gasifier had average biomass-to-char conversion efficiency of 16.6%. If the produced char is used as fuel, households could save 32% of fuel compared to use of three-stone open fire and 18% when char is used as biochar, for instance. Adoption of the gasifier can help to reduce the need for firewood collection, hence reducing impacts on the environment while saving on the amount of time and money spent on cooking fuel.

  • 48.
    Habib, Mustapha
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design.
    Bollin, Elmar
    Institute of Energy System Technology, Offenburg University of Applied Sciences, 77652 Offenburg, Germany.
    Wang, Qian
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggteknik och design. Uponor AB, Hackstavägen 1, 72132 Västerås, Sweden.
    Battery Energy Management System Using Edge-Driven Fuzzy Logic2023Ingår i: Energies, E-ISSN 1996-1073, Vol. 16, nr 8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Building energy management systems (BEMSs), dedicated to sustainable buildings, may have additional duties, such as hosting efficient energy management systems (EMSs) algorithms. This duty can become crucial when operating renewable energy sources (RES) and eventual electric energy storage systems (ESSs). Sophisticated EMS approaches that aim to manage RES and ESSs in real time may need high computing capabilities that BEMSs typically cannot provide. This article addresses and validates a fuzzy logic-based EMS for the optimal management of photovoltaic (PV) systems with lead-acid ESSs using an edge computing technology. The proposed method is tested on a real smart grid prototype in comparison with a classical rule-based EMS for different weather conditions. The goal is to investigate the efficacy of islanding the building local network as a control command, along with ESS power control. The results show the implementation feasibility and performance of the fuzzy algorithm in the optimal management of ESSs in both operation modes: grid-connected and islanded modes.

  • 49.
    Hagnestal, Anders
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknik, Elkraftteknik.
    On the Optimal Pole Width for Direct Drive Linear Wave Power Generators Using Ferrite Magnets2018Ingår i: Energies, E-ISSN 1996-1073, Vol. 11, nr 6, artikel-id 1356Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, ferrite magnet linear generators for wave power applications are considered. These machines operate at unusually low speeds, around and even below 1 m/s, at which the optimal geometry differs from standard machines, since the copper loss and the force density become considerably more important. The focus is on translator design, and analytical two-dimensional (2D) expressions for the optimal 2D geometry are derived. Finite Element Analysis (FEA) is also applied to verify the analytical expressions and to determine effects from leakage fluxes and iron saturation. Demagnetization of ferrite magnets is also discussed and calculations are made to show the demagnetization situation for the magnets in different geometries. Finally, an example generator design is made to illustrate the findings. This generator is compared to three other generator concepts. It is concluded that ferrite magnet generators can have at least nearly the same shear stress as surface mounted neodymium magnet generators at low speed if the airgap is 3 mm or less, provided that a proper pole length is chosen, and that they can be economically competitive to neodymium magnet generators for wave power. It is also concluded that the demagnetization situation for the magnets can be severe, and that the choice of magnet grade and pole length is crucial in this respect.

  • 50.
    Harahap, Fumi
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis (IIASA).
    Sennai, Mesfun
    International Institute for Applied Systems Analysis (IIASA).
    Khatiwada, Dilip
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    Kraxner, Florian
    International Institute for Applied Systems Analysis (IIASA).
    Silveira, Semida
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    Opportunities to Optimize the Palm Oil Supply Chain in Sumatra, Indonesia2019Ingår i: Energies, E-ISSN 1996-1073, Vol. 12, nr 3, artikel-id 420Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Significant amounts of biomass residues were generated in Indonesia. While untreated, residues emit greenhouse gases during the decomposition process. On the other hand, if efficiently utilized, these residues could be used to produce value-added products. This study investigates opportunities for harnessing the full potential of palm oil residues (i.e., empty fruit bunches, kernel shells, fiber, and mill effluent). As far as we are aware, the study is the first attempt to model the palm oil supply chain in a geographically explicit way while considering regional infrastructures in Sumatra Island, Indonesia. The BeWhere model, a mixed integer linear programming model for energy system optimization, was used to assess the costs and benefits of optimizing the regional palm oil supply chain. Different scenarios were investigated, considering current policies and new practices leading to improved yields in small-scale plantations and power grid connectivity. The study shows that a more efficient palm oil supply chain can pave the way for the country to meet up to 50% of its national bioenergy targets by 2025, and emission reductions of up to 40 MtCO2eq/year. As much as 50% of the electricity demand in Sumatra could be met if residues are efficiently used and grid connections are available. We recommend that system improvements be done in stages. In the short to medium term, improving the smallholder plantation yield is the most optimal way to maximize regional economic gains from the palm oil industry. In the medium to long term, improving electricity grid connection to palm oil mills could bring higher economic value as excess electricity is commercialized.

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