Losses of flywheel energy storages and joint operation with solar cells

Kohari, Z.; Vajda, István

doi:10.1016/j.jmatprotec.2004.07.057

Cited by 16 publications

(8 citation statements)

References 8 publications

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“…They are resistant to temperatures and deep discharge and have simple charge level monitoring [245]. The efficiency at rated power is also high, around 90% [78,144,159].…”

Section: Flywheelsmentioning

confidence: 99%

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Review of energy system flexibility measures to enable high levels of variable renewable electricity

Lund

Lindgren

Mikkola

et al. 2015

Renewable and Sustainable Energy Reviews

1,294

578

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Title: Review of energy system flexibility measures to enable high levels of variable renewable electricity Article Type: Review Article Keywords: energy system flexibility; DSM; energy storage; ancillary service; electricity market; smart grid Abstract: The paper reviews different approaches, technologies, and strategies to manage large-scale schemes of variable renewable electricity such as solar and wind power. We consider both supply and demand side measures. In addition to presenting energy system flexibility measures, their importance to renewable electricity is discussed. The flexibility measures available range from traditional ones such as grid extension or pumped hydro storage to more advanced strategies such as demand side management and demand side linked approaches, e.g. the use of electric vehicles for storing excess electricity, but also providing grid support services. Advanced batteries may offer new solutions in the future, though the high costs associated with batteries may restrict their use to smaller scale applications. Different "P2Y"-type of strategies, where P stands for surplus renewable power and Y for the energy form or energy service to which this excess in converted to, e.g. thermal energy, hydrogen, gas or mobility are receiving much attention as potential flexibility solutions, making use of the energy system as a whole. To "functionalize" or to assess the value of the various energy system flexibility measures, these need often be put into an electricity/energy market or utility service context. Summarizing, the outlook for managing large amounts of RE power in terms of options available seems to be promising. AbstractThe paper reviews different approaches, technologies, and strategies to manage large-scale schemes of variable renewable electricity such as solar and wind power. We consider both supply and demand side measures. In addition to presenting energy system flexibility measures, their importance to renewable electricity is discussed. The flexibility measures available range from traditional ones such as grid extension or pumped hydro storage to more advanced strategies such as demand side management and demand side linked approaches, e.g. the use of electric vehicles for storing excess electricity, but also providing grid support services. Advanced batteries may offer new solutions in the future, though the high costs associated with batteries may restrict their use to smaller scale applications. Different -P2Y‖-type of strategies, where P stands for surplus renewable power and Y for the energy form or energy service to which this excess in converted to, e.g. thermal energy, hydrogen, gas or mobility are receiving much attention as potential flexibility solutions, making use of the energy system as a whole. To -functionalize‖ or to assess the value of the various energy system flexibility measures, these need often be put into an electricity/energy market or utility service context. Summarizing, the outlook for managing large amounts of RE power in terms of options avai...

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“…They are resistant to temperatures and deep discharge and have simple charge level monitoring [245]. The efficiency at rated power is also high, around 90% [78,144,159].…”

Section: Flywheelsmentioning

confidence: 99%

“…The efficiency at rated power is also high, around 90% [78,144,159]. Disadvantages include modest energy capacity [171], high self-discharge rate on the order of 0.5% of stored energy per hour [246] and safety issues due to high-speed moving parts [245].…”

Section: Flywheelsmentioning

confidence: 99%

Review of energy system flexibility measures to enable high levels of variable renewable electricity

Lund

Lindgren

Mikkola

et al. 2015

Renewable and Sustainable Energy Reviews

1,294

578

View full text Add to dashboard Cite

show abstract

“…The specifications of the flywheel system including the air density values at 20 • C and atmospheric pressure conditions are provided in Table 1. The standby windage loss of the system at different speeds and pressure levels is estimated with help of Equations (1)-(3) and power loss expressions due to windage drag as derived and presented in Equations (11) and (15). Results of windage loss calculations for a constant air gap of 1 mm and a range of pressure levels between 0.001-100 Pa are presented in Figure 5.…”

Section: Aerodynamic Drag Lossesmentioning

confidence: 99%

“…Mitigation of losses in FESS and analysis of different components of losses contributing to the total loss is discussed in [14]. The losses of a flywheel system operating with solar cells are studied in [15]. References [16][17][18][19] mainly address the losses in the electrical machine part of the FESS which are typically small in comparison to the losses in its rotor part.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Standby Losses and Charging Cycles in Flywheel Energy Storage Systems

Amiryar

Pullen

2020

Energies

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Aerodynamic drag and bearing friction are the main sources of standby losses in the flywheel rotor part of a flywheel energy storage system (FESS). Although these losses are typically small in a well-designed system, the energy losses can become significant due to the continuous operation of the flywheel over time. For aerodynamic drag, commonly known as windage, there is scarcity of information available for loss estimation since most of the publications do not cover the partial vacuum conditions as required in the design of low loss energy storage flywheels. These conditions cause the flow regime to fall between continuum and molecular flow. Bearings may be of mechanical or magnetic type and in this paper the former is considered, typically hybridized with a passive magnetic thrust bearing. Mechanical bearing loss calculations have been extensively addressed in the open literature, including technical information from manufacturers but this has not previously been presented clearly and simply with reference to this application. The purpose of this paper is therefore to provide a loss assessment methodology for flywheel windage losses and bearing friction losses using the latest available information. An assessment of windage losses based on various flow regimes is presented with two different methods for calculation of windage losses in FESS under rarefied vacuum conditions discussed and compared. The findings of the research show that both methods closely correlate with each other for vacuum conditions typically required for flywheels. The effect of the air gap between the flywheel rotor and containment is also considered and justified for both calculation methods. Estimation of the bearing losses and considerations for selection of a low maintenance, soft mounted, bearing system is also discussed and analysed for a flywheel of realistic dimensions. The effect of the number of charging cycles on the relative importance of flywheel standby losses has also been investigated and the system total losses and efficiency have been calculated accordingly.

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“…The flywheel is proving to be an ideal form of energy storage on account of its high efficiency, long cycle life, wide operating temperature range, freedom from depth-of-discharge effects, and higher power and energy density-on both a mass and a volume basis [1][2][3] . Flywheel energy storage (FES) can have energy fed in the rotational mass of a flywheel, store it as kinetic energy, and release out upon demand.…”

Section: Introductionmentioning

confidence: 99%

Superconducting energy storage flywheel—An attractive technology for energy storage

Tang

Liu

Fang

2010

J. Shanghai Jiaotong Univ. (Sci.)

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Flywheel energy storage (FES) can have energy fed in the rotational mass of a flywheel, store it as kinetic energy, and release out upon demand. The superconducting energy storage flywheel comprising of magnetic and superconducting bearings is fit for energy storage on account of its high efficiency, long cycle life, wide operating temperature range and so on. According to the high temperature superconducting (HTS) cooling mode, there are zero field cooling (ZFC) bearings and field cooling (FC) bearings. In practice, the superconducting bearings are formed by field-cooled superconductors and permanent magnets (PMs) generally. With respect to the forces between a permanent magnet and a superconductor, there are axial (thrust) bearings and radial (journal) bearings. Accordingly, there are two main types of high-temperature superconducting energy storage flywheels, and if a system comprising both the thrust bearing and the radial bearing will have the characteristics of both types of bearings. Magnetic force, magnetic stiffness and damping are these three main parameters to describe the levitation characteristics. Arrangement and shape of superconductors, thickness of superconductor, superconducting flux creep and critical current density of the superconductor affect the magnetic levitation force of these superconducting bearings. The key factors of FES technology, such as flywheel material, geometry, length and its support system were described, which directly influence the amount of energy storage and flywheel specific energy. All these results presented in this paper indicate that the superconducting energy storage flywheel is an ideal form of energy storage and an attractive technology for energy storage.

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Losses of flywheel energy storages and joint operation with solar cells

Cited by 16 publications

References 8 publications

Review of energy system flexibility measures to enable high levels of variable renewable electricity

Review of energy system flexibility measures to enable high levels of variable renewable electricity

Analysis of Standby Losses and Charging Cycles in Flywheel Energy Storage Systems

Superconducting energy storage flywheel—An attractive technology for energy storage

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