Energiespeicher

Rummich, Erich

doi:10.1007/s00502-013-0152-2

Cited by 3 publications

(5 citation statements)

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“…MES might be more infrastructure-friendly considering that less cavern volume is required and that state-ofthe-art systems for transportation and electricity generation of natural gas can be used for renewable methane. This assumption is based on the high content of methane in natural gas [19].…”

Section: Discussionmentioning

confidence: 99%

Life cycle assessment of conversion processes for the large-scale underground storage of electricity from renewables in Europe

Pérez

Vogt

2014

EPJ Web of Conferences

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Abstract. This study estimates the total storage capacity for renewable energies in European salt caverns up to the year 2030 in order to deal with the fluctuation of renewable energies. The round-trip efficiencies and the CO 2 equivalent direct emissions of the different storage process stages are taken into account. These are transmission, electricity to gas conversion, storage and re-electrification from gas to electricity, of three different energy carriers, namely compressed air, hydrogen and renewable methane.

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Section: Discussionmentioning

confidence: 99%

Life cycle assessment of conversion processes for the large-scale underground storage of electricity from renewables in Europe

Pérez

Vogt

2014

EPJ Web of Conferences

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“…where ∆ϑ is the difference between the medium temperature ϑ m and the surrounding temperature ϑ s . The first-order differential equation with constant coefficients is as follows [24,25]:…”

Section: Thermal Analysismentioning

confidence: 99%

Lifetime Assessment of PILC Cables with Regard to Thermal Aging Based on a Medium Voltage Distribution Network Benchmark and Representative Load Scenarios in the Course of the Expansion of Distributed Energy Resources

et al. 2021

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The decentralized feed-ins from distributed energy resources (DER) represent a significant change in the manner in which the power grid is used. If this leads to high loads on electrical equipment, its aging can be accelerated. This applies in particular with regard to the thermal aging of older generations of power cables, namely paper insulated lead covered (PILC) cables. This type of power cable can still be found frequently in medium voltage (MV) networks. If aging of these cables is significantly accelerated in the presence of DER, distribution system operators (DSO) could face unplanned premature cable failures and a high replacement demand and costs. Therefore, this paper investigates the thermal aging of PILC cables in a MV distribution network benchmark for different load scenarios, using standardized load profiles and representative expansion scenarios for wind power and photovoltaics plants in particularly affected network areas in Germany. A main objective of this paper is to present a methodology for estimating the thermal degradation of PILC cables. An approach is used to draw simplified conclusions from the loading of cables to their conductor or insulation temperature. For this purpose, mainly Joule losses are considered. In addition, thermal time constants are used for the heating and cooling processes. Based on the insulation temperature, thermal aging is determined using the Arrhenius law or the Montsinger rule. However, it is important to note that there is an urgent need for research on reference data in this area. For this reason, the results of the lifetime estimation presented in this paper should only be considered as an approximation if the selected reference data from the literature for the aging model are actually applicable. The lifetime assessment is performed for a highly utilized line segment of the network benchmark. Accordingly, extreme values are examined. Different operational control strategies of DSO to limit cable utilization are investigated. The results show that the expansion of DER can lead to a short but high cable utilization, although the average utilization does not increase or increases only slightly. This can lead to significantly lower cable lifetimes. The possible influence of these temporarily high loads is shown by comparing the resulting cable lifetime with previous situations without DER. It is also shown that DSO could already reduce excessive aging of PILC cables by preventing overloads in a few hours of a year. In addition to these specific results, general findings on the network load due to the influence of DER are obtained, which are of interest for congestion management.

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“…In addition, the liquids were merged in a micro mixer (Part No. 1446-A-9.0) which was designed and manufactured by the Institute of Micro Process Engineering (IMVT, Eggenstein-Leopoldshafen, Germany) 3 . Two identically-manufactured cross-flow micro heat exchangers (Part No.…”

Section: Porous Membranesmentioning

confidence: 99%

“…Unfortunately, due to the low energy capacity of conventional electrochemical accumulators e.g., lithium ion batteries, this kind of energy supply or recharging systems (power banks) are no longer appropriate for long operating times. To overcome short operating times, many possibilities are currently being investigated to replace lithium ion battery-based energy supplies or recharging systems [1][2][3]. Small-sized membrane-based fuel cell systems with a highly specific energy density are among the most promising candidates to overcome short operating times.…”

Section: Introductionmentioning

confidence: 99%

“…Using a micro direct methanol fuel cell (µDMFC) based on a lab-on-a-chip (LOC) design, integrated fuel supply for methanol, and a separation system, the operating time can be extended significantly without increasing the weight or volume of the portable device disproportionately. In addition, the µDMFC can be refuelled instantly with methanol, which is an easily storable, convenient liquid fuel with an energy density of 4.42 kWh/dm 3 [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of the Gas/Liquid Phase Separation Using a Membrane-Based Micro Contactor

et al. 2018

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The gas/liquid phase separation of CO2 from a water-methanol solution at the anode side of a µDirect-Methanol-Fuel-Cell (µDMFC) plays a key role in the overall performance of fuel cells. This point is of particular importance if the µDMFC is based on a “Lab-on-a-Chip” design with transient working behaviour, as well as with a recycling and a recovery system for unused fuel. By integrating a membrane-based micro contactor downstream into the µDMFC, the efficient removal of CO2 from a water-methanol solution is possible. In this work, a systematic study of the separation process regarding gas permeability with and without two-phase flow is presented. By considering the µDMFC working behaviour, an improvement of the overall separation performance is pursued. In general, the gas/liquid phase separation is achieved by (1) using a combination of the pressure gradient as a driving force, and (2) capillary forces in the pores of the membrane acting as a transport barrier depending on the nature of it (hydrophilic/hydrophobic). Additionally, the separation efficiency, pressure gradient, orientation, liquid loss, and active membrane area for different feed inlet temperatures and methanol concentrations are investigated to obtain an insight into the separation process at transient working conditions of the µDMFC.

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Energiespeicher

Cited by 3 publications

References 0 publications

Life cycle assessment of conversion processes for the large-scale underground storage of electricity from renewables in Europe

Life cycle assessment of conversion processes for the large-scale underground storage of electricity from renewables in Europe

Lifetime Assessment of PILC Cables with Regard to Thermal Aging Based on a Medium Voltage Distribution Network Benchmark and Representative Load Scenarios in the Course of the Expansion of Distributed Energy Resources

Experimental Investigation of the Gas/Liquid Phase Separation Using a Membrane-Based Micro Contactor

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