Electrical Storage Technologies Research Articles

Increasing the Efficiency of Recuperation Through the Use of Energy Storage Systems for the Own Needs of Traction Substations

The use of regenerative braking by electric rolling stock on DC railways makes it possible to increase the energy efficiency of the transportation process. The effective use of regenerative braking is associated with creation of conditions for receiving energy obtained through it. For these purposes, rectifier-inverter converters and energy absorbing devices are currently used in the traction power supply system.A promising technology that provides an increase in theefficiency of the use of regenerative braking is energy storage, which allows this energy to be used in the future to cover the traction load curve. A feature of the use of regenerative braking on singletrack sections of DC railways with low traffic intensity is the need to use converters or energy absorbing devices. One of the options for increasing the efficiency of recuperation energy use is the adoption of energy storage systems for the own needs of traction substations. The use of this technical solution is advisable on single-track sections with intensive use of regenerative braking, the effectiveness of which is explained through a decrease in power consumption for own needs of the substation from the external grid.The international research allows us to identify the widespread trend towards the application of electricity storage technology in various fields: from renewable energy sources to electric power systems, including transport power supply systems. International practices demonstrate successful implementation of pilot projects of adoption of energy storage systems for solving problems of increasing the efficiency of electric urban and suburban transport, as well as of metro systems.The objective of the work is to assess the energy performance of energy storage systems when using recovered energy for own needs of a traction substation. The study is based on the methods of mathematical and simulation modelling, optimisation, and mathematical statistics.The discussed issues refer to the use of energy storage systems to provide power supply for own needs of DC traction substations. Main issues of operation of storage systems are considered with the help of a substation case study. The features of the recuperation load curve are described to explain the use of hybrid technologies for developing a storage system. The example of the considered traction substation helps to demonstrate the solution to the problem of determining main parameters of the storage system, considering the specifics of operation of electrochemical and electrical modules.

Techno-economic analysis of long-duration energy storage and flexible power generation technologies to support high-variable renewable energy grids

Techno-economic analysis of long-duration energy storage and flexible power generation technologies to support high-variable renewable energy grids

Low-Cost Flow Battery Active Materials for Long Duration Storage

Energy storage capacity is presently dominated by pumped-hydroelectric storage, but the past decade has brought increasing levels of electrochemical energy storage (EES) installations.1 As more EES gets added to the grid, policymakers have recognized the need for longer-duration systems and sought systems that can provide durations of 8+ hours.2 , 3 At these longer durations, redox flow batteries (RFBs) have an advantage over Li-ion systems since the marginal cost of another hour duration asymptotes to the cost of additional active materials and their storage containers, rather than additional cells, packs and modules.Leading vanadium RFBs have made cost reductions by improving the power density of their energy conversion stacks,4 , 5 but eventually are limited by the relatively high, incremental cost of their vanadium active materials. Switching to lower cost active materials can permit economically feasible long duration RFB systems.6 Raytheon Technologies Research Center has previously reported on the proposed sulfur-manganese (S-Mn) chemistry, which uses active materials based on low-cost sulfur, a waste product of fossil fuel production, and inexpensive manganese, an element presently used commercially in disposable primary cells. The team has implemented electrolyte takeover RFB technology, which has made low-cost S-Mn systems feasible despite crossover-induced precipitation that hampers performance levels.7 This technology implementation has allowed S-Mn sub-scale (20+ cm2) cell operation for 1000+ hours.Additionally, development of another low-cost chemistry, relying on ligand-coordinated metal centers,8 has showed promising early results. This chemistry, which relies on a more neutral solution pH, brings new challenges, such as managing pH in an environment where small absolute concentration changes have outsized effect, but comes with benefits such as wide electrochemical stability windows.Techno-economic analysis suggests that these two chemistries present an opportunity to deliver competitively priced long duration EES systems. This abstract will focus on the progress made advancing these two chemistries toward industrial relevance. Acknowledgements: The work presented herein was funded by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR000994. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. References Chalamala, B., DOE Global Energy Storage Database. Sandia National Laboratories: 2020.Padilla, M., Joint Long Duration Storage Request for Offers. Energy, S. V. C., Ed. Silicon Valley Clean Energy: 2020.Albertus, P.; Manser, J. S.; Litzelman, S., Long-Duration Electricity Storage Applications, Economics, and Technologies. Joule 2020, 4 (1), 21-32.Sun, C. N.; Mench, M. M.; Zawodzinski, T. A., High Performance Redox Flow Batteries: An Analysis of the Upper Performance Limits of Flow Batteries Using Non-aqueous Solvents. Electrochimica Acta 2017, 237, 199-206.Perry, M. L.; Darling, R. M.; Zaffou, R., High Power Density Redox Flow Battery Cells. ECS Transactions 2013, 53 (7), 7-16.Wadia, C.; Albertus, P.; Srinivasan, V., Resource constraints on the battery energy storage potential for grid and transportation applications. Journal of Power Sources 2011, 196 (3), 1593-1598.Saraidaridis, J. D.; Yang, Z.; Darling, R. M.; Perry, M. L., Recovering from Precipitation Events in Redox Flow Batteries. ECS Meeting s 2020, MA2020-01 (3), 472-472.Robb, B. H.; Farrell, J. M.; Marshak, M. P., Chelated Chromium Electrolyte Enabling High-Voltage Aqueous Flow Batteries. Joule 2019, 3 (10), 2503-2512.

Phase-field Determination of NaSICON Materials in the Quaternary System Na2 O-P2 O5 -SiO2 -ZrO2 : The Series Na3 Zr3-x Si2 Px O11.5+x/2.

Two types of solid electrolytes have reached technological relevance in the field of sodium batteries: ß/ß”‐aluminas and NaSICON‐type materials. Today, significant attention is paid to room‐temperature stationary electricity storage technologies and all‐solid‐state Na batteries used in combination with these solid electrolytes are an emerging research field besides sodium‐ion batteries. In comparison, NaSICON materials can be processed at lower sintering temperatures than the ß/ß”‐aluminas and have a similarly attractive ionic conductivity. Since Na2O−SiO2−ZrO2−P2O5 ceramics offer wider compositional variability, the series Na3Zr3–xSi2PxO11.5+x/2 with seven compositions (0≤x≤3) was selected from the quasi‐quaternary phase diagram in order to identify the predominant stability region of NaSICON within this series and to explore the full potential of such materials, including the original NaSICON composition of Na3Zr2Si2POl2 as a reference. Several characterization techniques were used for the purpose of better understanding the relationships between processing and properties of the ceramics. X‐ray diffraction analysis revealed that the phase region of NaSICON materials is larger than expected. Moreover, new ceramic NaSICON materials were discovered in the system crystallizing with a monoclinic NaSICON structure (space group C2/c). Impedance spectroscopy was utilized to investigate the ionic conductivity, giving clear evidence for a dependence on crystal symmetry. The monoclinic NaSICON structure showed the highest ionic conductivity with an optimum ionic conductivity of 1.22×10−3 at 25 °C for the composition Na3Zr2Si2PO12. As the degree of P5+ content increases, the total ionic conductivity is initially enhanced until x=1 and then decreases again. Simultaneously, the increasing amount of phosphorus leads a decrease in the sintering temperatures for all samples, which was confirmed by dilatometry measurements. The thermal and microstructural properties of the prepared samples are also evaluated and discussed.

Transient simulation and thermodynamic analysis of pumped thermal electricity storage based on packed-bed latent heat/cold stores

Pumped thermal electricity storage is a promising large-scale electricity storage technology that uses thermodynamic cycles and thermal energy storage to achieve electricity storage and release. At present, for pumped thermal electricity storage based on the Joule-Brayton cycle, packed beds filled with sensible heat storage media are widely adopted as the thermal store, while they usually suffer from low energy storage densities and large volumes. In this paper, the thermodynamic feasibility of packed-bed latent heat/cold stores is explored to replace the packed-bed sensible heat/cold stores in pumped thermal electricity storage. A numerical model of a 10.5 MW/5 h storage system based on packed-bed latent heat/cold stores is established. The energy and exergy analysis of components is carried out. The effect of compression ratios, porosities, isentropic efficiencies, and inlet velocities on the systematic thermodynamic performance is investigated and optimal conditions are also investigated. It is concluded that the energy storage density of the system increases from 232.5 kWh/m3 to 245.4 kWh/m3 when packed-bed sensible heat/cold stores are replaced by latent ones. Furthermore, the power density of the system based on packed-bed latent heat/cold stores is 216.5 kW/m3, and the round-trip efficiency reaches 84.7%, which is competitive in large-scale electricity storage technologies.

Thermo-economic analysis of the pumped thermal energy storage with thermal integration in different application scenarios

Pumped thermal energy storage (PTES) refers to a promising electricity storage technology that converts electricity into heat using the heat pump for cheaper storage, and then converts it back into electricity through a heat engine. The integration of an additional low-grade heat source can increase the coefficient of performance (COP) of the heat pump and thus significantly improve the storage efficiency. To evaluate the economic impact of different heat sources including waste heat, solar, or district heating network, this paper constructs the thermodynamic and economic model of thermally integrated PTES (TI-PTES), evaluates the round-trip efficiency and storage cost in five typical scenarios, and explores the effects of key system parameters (storage temperature, temperature difference, component efficiency) and heat source conditions (flow rate, temperature). Results indicate that the storage efficiency competes with the storage cost and capacity for a fixed heat source condition. As the power-to-power efficiency increases from 50% to 120%, the cost could increase by 47%, while the storage capacity could decrease from 1544 kW to 163 kW with a heat source flow rate of 50 kg·s−1. Detailed parameter analysis indicates that a higher heat source flow rate/temperature leads to higher component efficiency. A smaller pinch point temperature difference results in higher efficiency or lower costs. In particular, the energy storage cost is more sensitive to the turbine's efficiency than that of compressor, so it is necessary to prioritize improving the turbine. In terms of typical heat source scenarios, TI-PTES is more suitable to couple with waste heat rather than district heating network or solar thermal scenarios, resulting in a minimum Levelized cost of storage (LCOS) of 0.23 $·kWh−1.

Inclusion of frequency control constraints in energy system investment modeling

This study investigates how the inclusion of frequency control constraints in electricity system modeling impacts the levels of investment and dispatch in electricity generation and storage technologies for futures that include high-level penetration of variable renewable energy. This is achieved using a linear cost-minimizing investment and dispatch model using historic load, wind and solar conditions from Spain, Ireland, Sweden and Hungary for Year 2050. With an hourly time-resolution, constraints are added so as to ensure that, within each hour, sufficient inertial power and reserves are available to control the frequency of the power grid. Comparing the results obtained with and without these constraints reveals that the main impacts on the results are from battery investments and operation. Furthermore, it is found that the reserve requirements exert a greater impact on system composition and operation than do the inertial power requirements.

Solar electricity storage through green hydrogen production: A case study

Electricity storage technologies appear as one of the solutions in most African country's national electrical grids issues. In this context, hydrogen production from renewable could be used to testing their ability for energy storage. It is possible to recover grid losses through hydrogen production and reinject it into the grid. This research aims at demonstrating numerically and experimentally how much renewable hydrogen can be produced in a sub-Saharan African context (Cotonou, Benin). Solar photovoltaic coupled to a proton exchange membrane (PEM) electrolyzer is built to demonstrate the hydrogen production followed by a model validation. The developed model accounting for all irradiation (not only the global horizontal) is simulated on MatLab-Simulink, and results fit the experimental data significantly. Results show 19% efficiency for solar hydrogen production of 115 L·day−1 knowing that lead-acid battery is included. Limits to the production rate are the storage pressure in the metal hydride tanks and the available electricity to be stored. Economic analysis through levelized cost of hydrogen (LCOH) shows that production of hydrogen from solar photovoltaic is about 1.09 €·m−3 under the present conditions. Storing renewable electricity through hydrogen might be cost-effective when disregarding certain constraints.

Interconnected Vertical δ-MnO2 Nanoflakes Coated by a Dopamine-Derived Carbon Thin Shell as a High-Performance Self-Supporting Cathode for Aqueous Zinc Ion Batteries

Aqueous zinc (Zn)-ion batteries (AZIBs) are one of the most promising secondary battery technologies for electricity storage with high performance-to-cost ratios. Herein, a highly reversible AZIB using interconnected vertical δ-MnO2 nanoflakes coated by a dopamine-derived carbon thin shell of ∼2 nm in thickness on carbon cloth as a self-supporting cathode is reported. The vertical nanoflake structure ensures the effective contact with electrolyte, large specific surface area and efficient stress relief during charge and discharge processes, and the coated thin carbon shell increases the electrical conductivity of the cathode and meanwhile relieves the dissolution of the electrode material during cycle. Thanks to these advantages, a high capacity of ∼346.7 mA h g–1 at 0.5 A g–1 and good long-term cycling stability with 96.8% capacity retention after 2000 cycles at 6.0 A g–1 can be delivered. Furthermore, the electricity storage mechanism is investigated using various characterization tools. Benefiting from the facile preparation and high performance, this study is believed to provide a valuable exploration of high-performance self-supporting cathodes for aqueous Zn-ion batteries.

Advanced exergy analysis of a Joule-Brayton pumped thermal electricity storage system with liquid-phase storage

Pumped thermal electricity storage is a thermo-mechanical energy storage technology that has emerged as a promising option for large-scale (grid) storage because of its lack of geographical restrictions and relatively low capital costs. This paper focuses on a 10 MW Joule-Brayton pumped thermal electricity storage system with liquid thermal stores and performs detailed conventional and advanced exergy analyses of this system. Results of the conventional exergy analysis on the recuperated system indicate that the expander during discharge is associated with the maximum exergy destruction rate (13%). The advanced exergy analysis further reveals that, amongst the system components studied, the cold heat exchanger during discharge is associated with the highest share (95%) of the avoidable exergy destruction rate, while during charge the same component is associated with the highest share (64%) of the endogenous exergy destruction rate. Thus, the cold heat exchanger offers the largest potential for improvement in the overall system exergetic efficiency. A quantitative analysis of the overall system performance improvement potential of the recuperated system demonstrates that increasing the isentropic efficiency of the compressor and turbine from 85% to 95% significantly increases the modified overall exergetic efficiency from 37% to 57%. Similarly, by increasing the effectiveness and decreasing the pressure loss factor of all heat exchangers, from 0.90 to 0.98 and from 2.5% to 0.5% respectively, the modified overall exergetic efficiency increases from 34% to 54%. The results of exergy analyses provide novel insight into the innovation, research and development of pumped thermal electricity storage technology.

The advent of modern solar-powered electric agricultural machinery: A solution for sustainable farm operations

With an uprising trend in cutting agriculture’s reliance on fossil fuels because of their limited supply and associated adverse impacts on the environment, the use of infrastructures adapted with alternative energy sources would be of crucial necessity. Among all renewable sources, solar energy has the highest compatibility with agricultural activities. The emergence of photovoltaic (PV) solar energy conversion technology in agriculture diminishes the need for oil-based fuels in this sector, offering a more affordable and sustainable electricity generation technique, and causing a remarkable reduction in greenhouse gas (GHG) emissions. In modern farm activities, the need for electrification has been raised, leading to the creation of a great opportunity for the employment of PV technology in this sector. The current study investigates the integration of PV technology with electric farm tractors and agricultural robots by discussing research works and commercial case studies. The results indicate that two major challenges against the widespread deployment of modern solar-powered electric farm machinery are high initial costs mainly associated with PV modules and battery storage units, along with deficiencies in electricity storage technologies. Due to operating in outdoor conditions, the effect of environmental parameters on the performance of PV modules integrated with agricultural machines including surface temperature, dust accumulation, shading, and air humidity should also be considered. Further technical improvements, cost reductions, and securing government incentives can facilitate the real-world deployment of these sustainable machines. This study is expected to promote the integration of PV technology with modern electric agricultural machinery and to encourage farmers, producers, planners, and decision-makers to employ this technique in mechanized agriculture by giving them an insight into the latest advances along with major challenges.

Energy, Electricity and Smart Grids in Latvia and Portugal – Developments and Concerns

This article explores the electricity sector of Latvia and Portugal, the European Union’s (EU) policy on clean energy, electricity, and smart technologies, the relationship developed between them, and the feasibility of smart grids’ and other new tools and technologies’ popularisation in the context of the Latvian and Portuguese electricity markets. As member states of the EU, Latvia, and Portugal must follow the decentralization agenda while increasing their use of encouraging renewable energy sources and establish better interconnection of electricity between their respective neighbouring member states. In this context, this article explores the electricity market of Latvia and Portugal, taking into account promising policies introduced by the EU that aim to incorporate new technologies such as storage solutions and the creation of smart grids. The article looks at how the priority of decentralized energy is being achieved in Latvia and Portugal. It explores the current domestic energy market in both countries, the current remarkable achievements in energy decentralization in terms of policy and legislation, as well as unique obstacles that have become apparent. It assesses new technologies and novel projects introduced to incentivize or further develop such technologies, namely smart metering systems, electric mobility, demand response, and electricity storage technologies. The article also looks at data protection concerns, the interconnection between the electricity markets of Portugal and Spain, and the possibility of a place in the market for the new clean energy sources. The article concludes the domestic reality in both countries and outlines a set of recommendations to facilitate the introduction of new technologies in the energy sector and how to further implement the decentralization of the electricity market.

Performance analysis of a Brayton Pumped Thermal Electricity Storage (PTES) with a liquid sensible heat storage

A pervasive Renewable Energy Source (RES) exploitation poses a wide range of issues to electric grids, which the enhancement of the electric grid flexibility may mitigate. There are several approaches to improve grid flexibility, and a significant help will come from efficient, reliable, durable and cheap electric storage technologies. Inevitably, different storage technologies will be needed since different power and energy spectra characterise RES issues. In the category of high capacity-to-power ratio technologies, Pumped Thermal Electricity Storage (PTES) is becoming more and more popular. Such technology aims at replacing Pumped Hydro Energy Storage (PHES), and it is suited for daily cyclic operation (load shifting). In this paper, a Brayton PTES with liquid sensible heat storages is studied. Compared to the standard system equipped with packed beds, the liquid heat storage allows for a more straightforward state of charge estimation, control and, potentially, for a better usage of storage volume. Through a parametric analysis involving the main design specifications, the system performance is assessed under realistic assumptions. The resulting figures provide an exhaustive characterisation of the performance achievable by the system, which may be useful for a fair comparison between PTES and other competing storage technologies.

Dynamic analysis and sizing optimization of a pumped hydroelectric storage-integrated hybrid PV/Wind system: A case study

The intermittent nature of variable renewable energy resources in conjunction with the fluctuating energy demand of load require using an efficient long-term energy storage means. Pumped Hydroelectric Storage (PHS) has proved its commercial viability as electricity storage technology and eligibility to be coupled with the Renewable Energy Systems (RESs). This paper proposes a simple and efficient procedure for optimal sizing of PHS-integrated hybrid PV/Wind power system for providing sustainable supply of electricity to an urban community in Brack city (27°32'N,14°17'E), Libya. The sizing procedure is considered as a constrained optimization problem. The constraints are developed to consider the operating conditions and the output uncertainty of RESs. The sizing algorithm and optimization procedure are explicitly described. Different operating scenarios were considered to identify the optimal size of the hybrid PV/Wind energy system and PHS. Using the measured date of climate conditions and load consumption, the energy production for different sizes of solar PV arrays and wind turbine farms were estimated by System Advisory Model (SAM) software. Based on the Levelized Cost Of Energy (LCOE), the optimum power capacity ratio of PV array to wind turbines farm was 1:5. For the system of optimal size, PHS contribute with a share of 15 % in covering the annual load energy. The obtained results revealed that coupling the hybrid RESs with PHS is cost competitive and reliable alternative for providing sustainable energy supply to urban areas of suitable topographical conditions and high potential of renewable energy resources.

Liquid Air Energy Storage for Decentralized Micro Energy Networks with Combined Cooling, Heating, Hot Water and Power Supply

Liquid air energy storage (LAES) has been regarded as a large-scale electrical storage technology. In this paper, we first investigate the performance of the current LAES (termed as a baseline LAES) over a far wider range of charging pressure (1 to 21 MPa). Our analyses show that the baseline LAES could achieve an electrical round trip efficiency (eRTE) above 60% at a high charging pressure of 19 MPa. The baseline LAES, however, produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at ∼1 MPa. Hence, the performance of the baseline LAES, especially at low charging pressures, is underestimated by only considering electrical energy in all the previous research. The performance of the baseline LAES with excess heat is then evaluated which gives a high eRTE even at lower charging pressures; the local maximum of 62% is achieved at ∼4 MPa. As a result of the above, a hybrid LAES system is proposed to provide cooling, heating, hot water and power. To evaluate the performance of the hybrid LAES system, three performance indicators are considered: nominal-electrical round trip efficiency (neRTE), primary energy savings and avoided carbon dioxide emissions. Our results show that the hybrid LAES can achieve a high neRTE between 52% and 76%, with the maximum at ∼5 MPa. For a given size of hybrid LAES (1 MW×8 h), the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton, respectively. These new findings suggest, for the first time, that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.

Oxygen Electrode Reaction of Titanium Oxide-Based Materials in Alkaline Solution

1. Introduction In order to expand usage of renewable energies, it should be required for improving electricity storage technology from the viewpoint of power supply in the disaster such as earthquake in Japan and power sources for remote islands where it is hard to establish infatuation of power grids. For a large scale, it is expected to develop for hydrogen storage such as Power-to-Gas including alkaline water electrolysis (AWE). For a small scale, electric power storage such as batteries including metal-air secondary batteries (MASB). In both devices, the oxygen electrode plays an important role. However, it's already reported that the degradation of Ni in the AWE anode was occurred by potential cycling simulated as fluctuating power derived from renewable energy 1), and the durability and activity for positive electrode (air electrode) of MASB must be improved significantly 2). In our previous study, we focused on Ti oxide-based material because of its abundant resources and stability and tried to apply it with and without doping Zr or Ce as the oxygen electrode for AWE and MASB 3-4). In this study, we have investigated the oxygen electrode reaction of Zr and Ce-doped titanium oxide-based material in alkaline solution. 2. Experimental Two types of TiOx doping with 1 mol% of Zr and Ce (ZrCe-TiOx as shown in the following section) and without doping were prepared under oxygen starvation atmosphere, and then formed as rod shape (φ=5.0 mm, Toshima manufacturing Co., Ltd.). Electrochemical measurements were performed at 30 ± 0.5°C using a TiOx or ZrCe-TiOx rod described in above, reversible hydrogen electrode (RHE) and glassy carbon plate as working, reference and counter electrodes in a three-electrode cell filled with 0.1 mol dm-3 KOH solution. After the pretreatment, cyclic voltammetry (CV) was carried out for the scan rate of 50 mV s-1, and the electric double layer capacity was calculated from the current data. In order to evaluate the catalytic activity for the OER, slow scan voltammetry (SSV) was performed in the potential range of 1.2 to 2.0 V for the scan rate of 5 mV s-1. As a durability simulation against potential fluctuations, a potential cycling test was performed at 1 V s-1 and a triangular wave of 0 to 2.0 V for 5,000 cycles, then the electric double layer capacity and SSV were measured again under the same conditions, and this sequence was repeated 4 times. This means that potential cycling test is completed for 20,000 cycles. 3. Results and discussion Each electrical resistivity of the sample was around 1 to 5 Ω cm, and no significant difference was observed with and without doping. Although the resistance after electrochemical measurement was increased for all samples, the resistance values kept in same digit. Fig. 1 shows Tafel plots of OER on TiOx before the potential cycling test. The horizontal axis is the common logarithm of the current density, i geo,normalized by the geometric area. Tafel region of each sample was observed from 1.6 to 1.7 V. In addition, the i geo at 1.7 V was used as an index of the OER activity in this study. The Tafel slope of ZrCe-TiOx was larger than that of TiOx, and the OER activity of TiOx was higher than that of ZrCe-TiOx. As a result, doping Zr and Ce didn't contribute to enhance the OER activity of TiOx. The durability of sample was evaluated by the comparison between initial OER activity and that after potential cycling. We also used the i geo at 1.7 V as an index of OER activity. Figure 2 shows the i geo of ZrCe-TiOx at 1.7 V during the potential cycling test. From Fig. 2, the OER activity after 20,000 cycle was 40% lower than initial OER activity. Though the OER activity was decreased 40% in 5,000 cycle, the i geo at 1.7 V was almost same from 5,000 to 20,000 cycle. It is suggested that the degradation of OER activity on ZrCe-TiOx was suppressed after 5,000 cycle in this study.Acknowledgment This work is partially supported by Toyota Mobility Foundation and the Suzuki Foundation. References1) H. Ichikawa. K. Matsuzawa, Y. Kohno, I. Nagashima, Y. Sunada, Y. Nishiki, A. Manabe, and S. Mitsushima, ECS Trans., 58 (33), 9 (2014).2) X. Li, A.L. Zhu, W. Qu, H. Wang, R. Hui, L. Zhang, and J. Zhang, Electrochim. Acta, 55, 5891 (2010).3) R. Suzuki, A. Ishihara, K. Ota and K. Matsuzawa, Proc. ECSJ Fall Meeting 2019, 1L10 (2019) (in Japanese).4) R. Suzuki, A. Ishihara, K. Ota and K. Matsuzawa, Proc. 26th FCDIC Fuel cell symp., p.95 (2019) (in Japanese). Figure 1

Transformation of Trolleybus Transport in Poland. Does In-Motion Charging (Technology) Matter?

Transport in cities is one of the most important sources of emissions. Electromobility is an essential element in the catalogue of activities of local authorities aimed at combating climate change. Over the years trolleybus transport has been characterised by both phases of development and regression and is still an essential component of zero-emission urban transport in about 300 cities worldwide. The development of electricity storage technology, especially in the form of a battery, has opened up new prospects for this mode of transport. A trolleybus equipped with a battery (in-motion charging technology) gains unique characteristics for operation independent of the catenary. This study presents the approach for assessing the development of in-motion charging for trolleybuses in all Polish cities operating this means of transport. A set of KPIs has therefore, been set and analysed. The analysis covers a comparison between 2014 and 2019, aimed at showing the development of technological innovations in this field. The results clearly show that in-motion charging technology leads to the development of trolleybus transport, although this development has mainly a qualitative dimension. A key factor determining the development of trolleybus transport using in-motion charging technology is progress in the development of traction batteries.

The value of storage in electricity generation: A qualitative and quantitative review

Abstract Electricity storage (ES) is a technology that can complement variable renewable generation in the widely sought low-carbon future. Given the several unique features of ES, it is important for utilities, investors, and regulators to understand how ES evaluation is conducted for effective deployment. Thus, this paper reviews how the literature associates a monetary value to ES technologies. It was found that evaluation has been done via the levelized cost of storage (LCOS) calculation, production-cost models, and market-based models. Each of these methods results in a monetary value different in nature: the LCOS provides a standalone average break-even cost, production-cost models provide overall cost savings gained for the entire power system from ES deployment, and market-based models provide the compensation that storage would receive if it were to compete in the market. Advantages and disadvantages of each method were discussed. The review revealed also that storage finds the most value in providing ancillary services. Given current market/regulatory restrictions, it is argued that in the near-term ES will be more valuable in vertically-integrated utilities as opposed to market environments. Finally, current ES deployment efforts can benefit from the previous renewables uptake that occurred in the past two decades.

Projecting the Competition between Energy-Storage Technologies in the Electricity Sector

Summary Low-cost electricity-storage technologies (ESTs) enable rapid decarbonization of energy systems. However, current EST cost estimates lack meaningful models to assess alternative market and technology scenarios. Here, we project the competition between six ESTs until 2030 and derive cost benchmarks. To this end, a system-dynamic simulation model operationalizes technology costs using component-based experience curves with cost floors for battery materials. We find that lithium-ion batteries are likely to outcompete alternative ESTs by 2030 across applications and largely independent of selected scenarios. This dominance can pose risks associated with technological lock-in. We, therefore, analyze different policy options and contend that it seems most promising to combine: (1) the support for development and commercialization of breakthrough storage concepts and (2) piggybacking on the strong improvement dynamics in lithium-ion batteries by fostering technology and knowledge spillovers that benefit the development of alternative active materials; battery designs; and adjacent, non-lithium-based technologies.

Comparative analysis of the supercapacitor influence on lithium battery cycle life in electric vehicle energy storage

Abstract Modern tendencies together with growing consciousness about the negative environmental influence of the transportation technologies have yielded electric vehicles as one of the approaches for phasing out fuel-based vehicles. Different directives aimed at increasing demand for electric vehicles have been put in place, however, due to different reasons initial predictions resulted in an insufficient number of sold units and suboptimal solutions like hybrid vehicles. Consequently, the reduction in fuel consumption and pollution generation is insignificant on a global scale. The main deficiency of the electric vehicle is its battery-based storage unit, which due to the current state of development makes the electric vehicle less admissible for consumers. Relatively short cycle life, high sensitivity to ambient conditions, environmental hazards, and relatively limited output power are only some of the deficiencies of the current battery technology. However, a novel type of electric storage technology has recently emerged as a promising long term complement to the battery technology. Long cycle life, huge power density, and no environmental hazards make supercapacitor technology a viable and assuring addition to the battery storage. Furthermore, supercapacitors may offer the possibility of making the electric vehicle more competitive on the market as well as a more sustainable solution. Although the supercapacitor technology is still considered to be immature and more research is needed, this paper examines the possibilities and effects of using supercapacitors as part of the electric vehicle energy storage. The main goal is the analysis of the positive effects that the supercapacitor storage can have on the battery cycle life as well as on the electric vehicle performance and economy. Conclusions drawn from the herein presented research are based on the theoretical analysis, numerical models, and experimental verification, therefore it can be confirmed that using supercapacitors as a part of electric vehicle energy storage substantial improvements in performance, durability, and economy could be achieved.