A review of energy storage systems in electricity markets.

A review of energy storage systems in electricity markets.

Zejneba Topalović ¹ , Reinhard Haas, Amela Ajanović, Marlene Sayer

Energy Economics Group, Vienna University of Technology, E-mail: zejneba.topalovic@student.tuwien.ac.at

Abstract:

Recent events in power systems: negative electricity prices, high fluctuations in the electricity market, and positive progress of a variable generation, have influenced the need for energy storage systems. These systems were first used as pumped hydro plants, but in recent years new types of storage have been developing, as the technology costs decrease and renewables installations increase. Policymakers defined a roadmap for reaching net-zero emissions by 2050., ensuring clean energy transition which has been questioned since the COVID-19 outbreak. At the beginning of the global pandemic, with the government restrictions and industrial setbacks, a decrease in CO2 emissions occurred for a short period. Demand drop and high supply of variable generation in the grids have been challenging for power systems operators. Since the global energy sector has been under disruptions and has influenced high socio-economic changes, a growing number of countries pledge net-zero emissions agreement, towards sustainable and clean energy development. With the Paris Agreement's goals for limiting global warming to 1,5 degrees Celsius, many countries are already going towards carbon neutrality ambitious targets. These goals are opening a set of new technologies, business opportunities, thus improving the economy. Measures for the implementation of the set goals and a higher share of renewable generation are already taken, showing that energy storage systems are becoming new emerging technology for balancing power grids. With projections of new solar by 2050. it is expected for the storage market to rise and balance possible price fluctuations. This paper presents a review of the up-to-date research on storage technologies, different grid applications, but also economic assessment.

A brief history of storage development is given, along with an overview of the technologies in the whole chain that explains their impact on total energy demand. There is a review of storage systems applications divided into different categories. Since there is obscure information about the costs of implementing storage systems, we provide a detailed review of cost analysis and feasibility of storage projects. This paper presents an energy storage review using the method of narrative. Collected up-to-date research on energy storage technologies, applications, environmental and economic assessment is published in a wide range of articles with high impact factors. Since, there is obscure research on relatively new technology such as energy storage, and especially their costs, global databases are used. The main contribution of this paper is a presentation of the current feasibility of these systems for investors and power operators and other market players. Finally, we present prospects derived from the presented review.

,Keywords: energy storage technologies, costs, storage feasibility, electricity market

1 Jungautor, +38762914462, zejneba.topalovic@student.tuwien.ac.at

1 Introduction

1.1 Motivation

IEA has built a roadmap for reaching net-zero emissions by 2050, ensuring clean energy transition in the energy sector. COVID-19 global pandemic has put energy transition into the perspective since it stopped green energy progress at the beginning. A setback of the industrial consumption and high variable generation in the grids have left clean energy transitions in the grey area, where it was predicted that after the pandemic, high industrial generation would postpone climate mitigation policies. (International Energy Agency, 2020) examines different scenarios of future pandemic solving with a focus on the next ten years and their impact on the energy sector. A rapid decline in renewable generation costs has boosted energy transformation with 9,6 GW installed capacity in 2019. (Irena, 2020). Since the global energy sector has been under disruptions and has influenced high socio-economic changes, a growing number of countries pledge net-zero emissions agreement, towards sustainable and clean energy development. According to the new IEA report(IEA, 2020), China and India are going to lead energy growth for the next year. India is facing extreme changes in the last 10 years, first due to extreme electrification and second due to high solar generation. Impact of lockdown measures, increase of renewable generation and drop in energy demand impact future need for long–term storage. Roadmap for India (India energy outlook report (IEA), 2015) renewable and storage development is an example for other countries, showing rapid changes in global emission mitigation. With the Paris Agreement's goals for limiting global warming to 1,5 degrees Celsius, many countries are already going towards carbon neutrality ambitious targets. These goals are opening a set of new technologies, business opportunities and are improving the economy. Measures were taken for the implementation of the set goals, and a higher share of renewable generation. Some countries have more than a 30% share of variable generation, which sometimes exceeds energy demand. Solar photovoltaics and onshore wind are dominating, attracting 46% and 29%, respectively, of global renewable energy investments, as seen in Figures 1,2, and 3. With projections of new solar by 2050., it is expected for the storage market to rise and balance possible price fluctuations.

Figure 1 Installed capacity trends of solar technology, source: (IRENA and CPI (2020), Global Landscape of Renewable Energy Finance, 2020)

0 100,000 200,000 300,000 400,000 500,000 600,000 700,000 800,000

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

In stal le d cap acit y [M W]

PV solar thermal

Figure 2 Installed capacity trends of wind technology, source: (IRENA and CPI (2020), Global Landscape of Renewable Energy Finance, 2020)

Figure 3 Annual financial commitments in renewable energy, source: (IRENA and CPI (2020), Global Landscape of Renewable Energy Finance, 2020)

1.2 Core objective

Energy storage as new technology has been used recently more in the light of flexibility needs.

As seen in Figure 4, pumped hydro storage is still leading with an installed storage capacity of 182 GW. According to collected data from World Energy Database [DOE], other storage technologies are still lagging behind historical installations of pumped hydro storage.

Nevertheless, energy storage systems are considered new emerging technology for adding flexibility to power grids. As (Irena, 2020) predicts, stationary storage (excluding EVs) would need to increase from 30 GWh today to 9000 GWh by 2050. These figures should be achieved through proper sizing and installing energy storage.

0 100,000 200,000 300,000 400,000 500,000 600,000 700,000 800,000

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

In sta lle d cap acity [ MW]

wind onshore wind offshore

1.3 Major literature

Energy storage has been recently revitalized subject, but it still lacks information. (Olabi et al., 2021) and (Koohi-Fayegh and Rosen, 2020) reviewed energy storage systems by mainly focusing on the technology and application. Hence, this review paper covers the gap by proposing an energy storage overview alongside economic criteria.

1.4 The organization of the paper

This paper is organized as follows: Section 2 gives a brief history of the storage development.

Section 4 gives an overview of the technologies, while Section 5 provides comprehensive reviews of the economic assessment. Section 6 shows environmental aspects. Following is Section 7 where the impact of energy policies is described, while the paper concludes with Section 8.

2 History of storage

First storage systems by some researchers (Danila, 2015) date back from 2200 years ago, considering archeological findings of a clay pot near Baghdad. Experiments showed that this ancient battery could produce 1.5 to 2 Volts, but scientists are still divided on this topic since it wasn't figured for what it was used. Later on, in the 19 ^th century, Volta experimented with copper and zinc and discovered Voltaic pile which led to series of discoveries of electrolysis and batteries that we know of today. Following this, Plante discovered a rechargeable Lead- acid battery. Throughout the century, batteries developed and were being used in large-scale systems, as Faure and Sellon improved batteries by placing the positive and negative electrodes in the spiral. Parallel development of the superconductors led to the possibility of

Pumped hydro storage

97%

Pumped hydro storage Compressed Air Energy Storage Electro-chemical

Electro- mechanical Hydrogen Storage

Lead-Carbon

Liquid Air Energy Storage Lithium Ion Battery

Compress ed Air Energy Storage

0%

Electro- chemical

7%

Electro- mechanic

al 39%

Hydrogen Storage

1%

Lead- Carbon

0% Liquid Air

Energy Storage

0%

Lithium Ion Battery

15%

Thermal Storage

38%

Figure 5 Installed energy storage capacities without pumped hydro storage [DOE]

Figure 4 Installed energy storage capacities

globally[DOE]

storing quantities of electricity in the magnetic fields (Vyas and Dondapati, 2020), (Salama and Vokony, 2020). Figure 6 illustrates the historical development of battery storage systems.

Figure 6 History of battery storage development

Pumped hydro storage systems started developing in the early 1900s, but now are the most used storage technology because of their characteristics to store a large amount of energy.

The system works on the principle of two reservoirs and the potential energy of water. When demand is high, electricity is produced by storing the water from the upper to the lower reservoir. At night, when demand is low, electricity from the grid is used to pump back up water, as seen in Figure 6. This system balances and adjusts the demand/supply, thus providing the stability of the power grids. Hence, pumped hydro storage is the most used storage technology with installed capacities of 181 GW globally [DOE]. The development of renewables technologies, their higher integration in power grids has led to a revitalization of already installed pumped hydro storage plants. Overcoming challenges in operating power grids with high shares of renewables is possible with storage technologies, especially ones with the application as bulk energy storage systems.

Figure 7 Pumped hydro storage principle [ EASE 2021]

Nevertheless, bulk energy storage systems, such as pumped hydro storage, development of

the batteries have continued, especially considering a variety of their application. With the

technical revolution in the late 1970s and the new emergence of the telephone and computer

technology, storage developed beside batteries, as supercapacitors were discovered. A

detailed description of the technology is given by (Chang and Hang Hu, 2018). An Exponential

increase in electric and hybrid vehicles influenced new research, but supercapacitors are still

behind the main competitor for these applications: Lithium-ion batteries. (Miao et al.,

2019),(Fang et al., 2020) and (Zubi et al., 2018) describe the progress and current state of Lithium-ion batteries.

3 Literature review

In this paper, three main research topics are in focus. Firstly, we consider the energy storage system's technical characteristics and application, then focus on the feasibility and economic assessment of these systems. Thirdly, we provide a comprehensive analysis of the flexibility and ancillary services of storage. Figure 8 presents collected information about storage systems in this paper and the main storage division concerning material, application, and future applications and RES development most important: feasibility.

Figure 8 Storage classification

Storage systems were first used as pumped-hydro plants (Al-hadhrami and Alam,

2015),(Barbour et al., 2016)(Hunt et al., 2020). During the peak hours, water potential was

used to generate electricity. When demand decreases in night hours, water was pumped back

up the hill, so it was reused the other day again for the electricity. This system was useful in

coordination with nuclear and fossil power plants which were non- dispatchable. Regardless

of pumped hydro storage capacity, geographical requirements are still a major constraint. In recent years, distributed generation has been influencing other storage technologies. Off-grid application of batteries in remote areas, together with solar generation is changing electricity market operation (Telaretti and Dusonchet, 2017). Depending on the renewable energy system application, battery energy storage system sizing methodology is chosen (Yang et al., 2018).

As there is high potential in using hybrid energy storage systems, some researchers found energy costs to be lower in comparison to single storage cases (Münderlein et al., 2020)(Javed et al., 2020). Pumped hydro storage power plants have been revitalized in recent years due to the flexibility mechanism of operating in the electricity market. Some countries' main plan for reaching targeted renewable shares, is investing in pumped hydro storage systems (Blakers et al., 2018). The profitability study shows a reduction in reserve capacity and investments in peaking units in Europe, as the storage capacities increase (Dallinger et al., 2019). The contribution of energy storage is caused by additional charging to replace generators in the merit order, capacity utilization and for renewable-induced systems (Soini, Parra and Patel, 2020). In recent literature, there has been a lack of energy storage economic parameters. Most of the literature is about dispatching and modeling renewable generation with energy storage (Santos et al., 2021),(Mohandes et al., 2021), (Mazzoni et al., 2019) or using mobile storage systems for unbalanced distribution grids (Nazemi et al., 2021). Alongside planning renewable generation, energy storage capacities must be considered and analyzed(Wu et al., 2021), as well as operational energy storage strategy (Habibi et al., 2020). Energy storage overview (Olabi et al., 2021) underlines increase in predictability method for RES, but as well economic perspective for further storage developments as in (AL Shaqsi, Sopian and Al-Hinai, 2020).

(Martin and Rice, 2021) make an analysis of future generation mix in Australia for minimizing

future outages risks and network failures using energy storage estimated increase of 19 GW

by 2041. Energy storage reviews (AL Shaqsi, Sopian and Al-Hinai, 2020) and (Das et al., 2018)

main concern is the capacity of energy storage, which lack proper description given from

production companies. In this paper wide range of literature is analyzed and collected. The

most valuable information about technical and economical parameters is provided,

respectively in Table 1 and Table 2. With all data collected, Table 3 gives an overview of all

possible storage applications.

Table 1 Energy storage characteristics

- - - 75-85 s-min 40-60 (>13000) (Das et al. , 2018)

0.1-0.2 0.2-2 0.2-2 70-80 >0.5x10⁴

0.5-1.5 0.5-1.5 0.5-1.5 70-85 >1000

0.01-0.10 0.5-1.3 0.3-1.3 65-90

- - 0.1-0.4 65-80 min 30-50 (Olabi et al. , 2021)

5-1000 - - - 70-89 1-15min 20-40(>13000) (Das et al. , 2018)

0.2-0.6 2-6 41-75

0.5-2 3-6 30-60

0.04-10 0.4-20 3-60 60-90

- - 3.2-5.5 70-73 - 30-40 (Olabi et al. , 2021)

- - 93-95 <4ms-s 15(>100000) (Das et al. , 2018)

5000 20-80 5-30 80-90 2x10⁴-10⁷

1000-2000 20-80 10-30 90-95 >2x10⁴

40-2000 0.3-400 5-200 70-96

- - 5-100 85 - 20 (Olabi et al. , 2021)

- - - 85-90 20ms-s 5-15 (1000-20000) (Das et al. , 2018)

1300-10000 200-400 60-200 85-98 500-10000

1500-10000 200-500 75-200 90-97 1000-10000

60-800 90-500 30-300 70-100 250-10000

0.1-50 - - 80-150 78-88 - 14-16 (Olabi et al. , 2021)

- - - 60-65 ms 10-20(2000-3500) (Das et al. , 2018)

75-700 15-80 15-40 60-80 1500-3000

80-600 60-150 50-75 60-70

40-140 15-150 10-80 60-90 300-10000

- - 30-50 72 - 13-20 (Olabi et al. , 2021)

- - - 70-90 5-10ms 3-15(2000) (Das et al. , 2018)

90-700 50-80 30-45 75-90 250-1500

10-400 50-80 30-50 70-80 500-1000

10-400 25-90 10-50 60-90 300-3000

- - 30-50 75-80 - 15 (Olabi et al. , 2021)

- - - 80-90 1ms 10-15(2500-4500) (Das et al. , 2018)

120-160 150-300 100-250 70-85 2500-4500

140-180 150-250 150-240 2500

1-50 150-350 100-240 65-90 1000-4500

- - 100-175 75-87 - 12-20 (Olabi et al. , 2021)

- - - 85 <1s 5-10(12000+) (Das et al. , 2018)

0.5-2 20-70 15-50 60-75

<2 16-33 10-30 75-85 >1.2x10⁴

10-30 10-50 60-90 800-1.6x10⁴

- - - (Olabi et al. , 2021)

- - - 25-58 <1s 5-20+(1000-20000+) (Das et al. , 2018)

>500 500-3000 800-10000 20-50 >1000

100-370 150-250 75-90

0.1-50 - - - 35-42 - 15 (Olabi et al. , 2021)

0-0.3 - - - 90-95 8ms 20+(>100000) (Das et al. , 2018)

2600 6 75-80

0.2-2.5 0.5-5 95-97 >2x10⁴

300-4000 0.2-14 0.3-75 80-99

0.05-0.25 - - 2-69 80-95 - 20 (Olabi et al. , 2021)

0-0.03 - - - 90-95 8ms 20+(>100000) (Das et al. , 2018)

40,000-120,000 10-20 1-15 85-98

>100,000 10-30 2.5-15 90-97

(Olabi et al. , 2021) -

-

-

-

-

-

-

-

-

-

-

-

- 15-4500 1-35 - 65-99

- 0-58.8

-

-

- 0.05-34 0.05-10

0.05-0.0534 0.03-03

-

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020) Lead -acid

Natrium Sulfur

Vanadium redox

Hydrogen Fuel Cell

Superconducting magnetic

Super capacitor

-

- 0-40

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020)

(Koohi-Fayegh and Rosen, 2020) Pumped hydro storage

Compressed Air Energy Storage

Flywheel

Lithium-ion Battery

Nickel-Cadmium

10-5000

10-1000 -

50-300 -

-

-

- 0.1-20

0.1-20 0-100

0-40

50

Type of storage Power Range MW Power density (voumetric) (kW/m3)

Energy density (voumetric) ( kWh/m3)

Energy density (mass) (kWh/kg)

Cycle efficicency

%

Response

time Lifetime(cycles) References

-6x

-3x

-

Table 2 Economic and environmental parameters of the storage

4 An overview of the technologies

In this chapter, we present a detailed review of all types of energy storage systems. Energy storage systems have different characteristics, as seen above, hence they are used for various applications, which is given in Table 3.

Pumped hydro 1700-2550 4.25-85 hr-months 1-24hr+ Large (Das et al. , 2018)

510-1700 4.25-85 (Koohi-Fayegh and Rosen, 2020)

10.2-71.4 (Olabi et al. , 2021)

Compressed air 340-850 1.7-102 hr-months 1-24hr+ Large (Das et al. , 2018)

340-680 1.7-42.5 (Koohi-Fayegh and Rosen, 2020)

3.4-71.4 (Olabi et al. , 2021)

Flywheel 212.5-297.5 850-11900 sec-min ms-15min Almost none (Das et al. , 2018)

255-850 2550-5100 (Koohi-Fayegh and Rosen, 2020)

340-680 (Olabi et al. , 2021)

Lithium- ion 765-3400 510-3230 min-days min-hr Moderate (Das et al. , 2018)

1020-3400 85-2125 (Koohi-Fayegh and Rosen, 2020)

765-1105 (Olabi et al. , 2021)

Lead-acid 255-510 170-340 min-days s-hr Moderate (Das et al. , 2018)

255-510 170-340 (Koohi-Fayegh and Rosen, 2020)

51-102 (Olabi et al. , 2021)

Nickle-Cadmium 425-1275 340-2040 min-days s-hr Moderate (Das et al. , 2018)

425-1275 680-1275 (Koohi-Fayegh and Rosen, 2020)

340-2040 (Olabi et al. , 2021)

Natrium-Sulfur 850-2550 255-425 sec-hr s-hr Moderate (Das et al. , 2018)

850-2550 255-425 (Koohi-Fayegh and Rosen, 2020)

212.5-456.45 (Olabi et al. , 2021)

Vanadium-Redox 510-1275 127.5-850 hr-months s-24hr+ Moderate (Das et al. , 2018)

850-2550 255-425 (Koohi-Fayegh and Rosen, 2020)

- - (Olabi et al. , 2021)

Capacitor 170-340 425-850 sec-hr ms-60min Small (Das et al. , 2018)

170-340 425-850 (Koohi-Fayegh and Rosen, 2020)

- - (Olabi et al. , 2021)

Supercapacitor 85-382.2 255-1700 sec-hr ms-60 min None (Das et al. , 2018)

110.5-437.75 8500 (Koohi-Fayegh and Rosen, 2020)

- - (Olabi et al. , 2021)

Magnetic 170-415.65 850-61200 min-hr ms-8s Moderate (Das et al. , 2018)

110.5-437.75 850-8500 (Koohi-Fayegh and Rosen, 2020)

6083.45-17000 (Olabi et al. , 2021)

Hydrogen 425-850 12.75 hr-months 1-24hr+ Small (Das et al. , 2018)

425-850 - (Koohi-Fayegh and Rosen, 2020)

11.9-15.3 (Olabi et al. , 2021)

Thermal CES 170-255 2.55-25.5 min-days 1-8 hr Bening (Das et al. , 2018)

170-255 2.55-51 (Koohi-Fayegh and Rosen, 2020)

- - (Olabi et al. , 2021)

Environmental

impact References

Type of storage Capital cost (power based) €/kW

Capital cost(energy

based) €/kWh Charge time Discharge time

Table 3 Technical characteristics for energy storage technologies

Type of storage

Installed capacities

MW

back- up power

bulk energy storage

bridging power

energy arbitrage

energy management

frequency regulation

increase of self- consumption

load balancing

long- term

medium- term

network operation

peak shaving

power quality

primary regulation

Pumped hydro storage 181911 * * * * * * * * *

Compressed Air Energy Storage 8,41 * * * * * * *

Flywheel Energy Storage - * * * * * *

Lead- acid - * * * * * * * * *

Lithium-ion 754,61 * * * * * * * * * *

Sodium- sulfur (NaS) - * * * * * * * *

Nickle- Cadmium - * * * *

Vanadium Redox Battery - * * * * * * * * * *

Zn- Br - * * * * * * * *

Type of storage PV self- consumption

renewable integration

reducing peak demand

renewables support

short- term

system operation

support of voltage regulation

time- shift

uninterrup ted power

supply

utility

wind energy curtailment

Storage duration

Pumped hydro storage * * * * 16 h discharge

Compressed Air Energy Storage * * * * 16 h discharge

Flywheel Energy Storage * * * 0.25 h discharge ( short)

Lead- acid * * * * * * * * 4 h discharge ( short and long

duration)

Lithium-ion * * * * * * * 4 h discharge ( medium term)

Sodium- sulfur (NaS) * * * * * long and short duration

Nickle- Cadmium * long and short duration

Vanadium Redox Battery * * * * * * * * long and short duration, 4 h discharge

Zn- Br * * * * long and short duration

4.1 Mechanical

4.1.1 Pumped hydro storage

(Al-hadhrami and Alam, 2015) presented review of the existing global PHES systems and hybrid systems such as solar PV-hydro and wind-hydro, questioning the technology for island grids and bulk storage systems. (Hunt et al., 2020) case study for pumped hydro storage large scale with innovative arrangements shows possibilities for storage with low topography variations and water availability. Some examples of countries' renewed interest in PHS (Dursun and Alboyaci, 2010) and analyses considering scenarios based on hourly prices (Barbaros, Aydin and Celebioglu, 2021). This evaluation shows that pricing policies on storage schemes provide infeasible projects. Pumped hydro storage can effectively manage energy variations in hybrid mode with battery bank, especially for off-grid renewable systems, as PHS and battery storage have complementary characteristics, complementing each other in the low state of charge periods(Javed et al., 2020).

4.1.2 Compressed air energy storage

As well as pumped hydro storage systems, compressed air energy storage systems depend on geographical locations. These systems utilize large underground storage caverns for providing large-scale and long-term electricity storage. In (King et al., 2021) recent large-scale CAES projects are presented alongside a method for utilizing these systems. Since operating non- dispatchable energy generation is quite challenging, the first economic characterization of offshore compressed air energy storage is given in (Li and Decarolis, 2015).

CAES is beside PHES systems, the most cost-efficient technology for large-scale application, but it is also limited with geographical position. Liquid air energy storage systems, on the contrary, have simple construction, regardless of geographical location, hence they are the main alternative to large-scale energy storage, reviewed in (Borri et al., 2021).

4.1.3 Flywheel

This type of storage, as an alternative to electrochemical energy storage systems because of the same characteristics of short-duration time, is examined from a techno-economic point of view (Rahman et al., 2021). Detailed principle of flywheel technology, application, development, and systems practice is given in (Arabkoohsar and Sadi, 2021). As flywheels application in peak shaving is important when analyzing the future of e-mobility, (Thormann, Puchbauer and Kienberger, 2021) investigate the economic and technical suitability of FESS for charging electric vehicle use cases. They find that electric buses can be operated with cost- efficiency when FESS is at the technical optimum.

4.2 Electrochemical Energy Storage Systems

Energy storage technologies reviews by (Behabtu et al., 2020) and (Yang et al., 2018) fill the

gap as stated, in storage literature and show potential for Li-ion batteries as fully integrated

parts of the grid. Battery energy storage has been developing recently hence the improvement

in electric vehicles production and decrease in the material costs. (Poullikkas, 2013) has compiled a dataset on large-scale storage systems and industrial storage systems, while (Figgener et al., 2020) shows a wide range of possibilities for further development, from currently 415 MW battery power installations in Germany.

Trends in the spreading of stationary batteries in the USA (Telaretti and Dusonchet, 2017), show that the profitability of ESS depends on the revenues, which is an indication for the stakeholders to ensure to compensate for storage costs. Most of the applications of battery energy storage have been used for electric vehicles, but recently more in end-user installations for self-consumption. One of the storage applications, market-oriented is price arbitrage, which shows potential in operation strategy with price differentials. (Metz and Saraiva, 2018) estimate the required price volatility in the German intraday market, to justify an investment in a 1 MW storage device. These calculations analyze battery technologies from the economic perspective as it is vital for their future usage. Simulation of hybrid battery storage systems, used as primary reserve control in (Münderlein et al., 2020) proved to be profitable because of the multi-use strategy. Other concerns about battery storage are durability and size, hence (Kelly and Leahy, 2020) explore optimal investment. Overview of different battery technologies of EVs and comparison regarding environmental impacts in (Balali and Stegen, 2021) indicates advantages and current limitations.

A lifetime of the batteries is the main issue for wider usage, hence the lower market price for lead-acid shows they are still operable for primary reserve and peak-shaving. (Fares and Webber, 2018) found greater benefit when increasing the life cycle of lead-acid batteries since they have lower cycle life than other batteries for which is better to increase calendar life.

Lithium-ion batteries are mainly used for distribution or household storage(Alimardani, Narimani and Member, 2021). Since self-consumption is increasing due to the decrease in solar technology costs, prosumers are a new group of storage users, who are slowly becoming local energy market players (El-batawy, Morsi and Member, 2021) (Shen et al., 2021)(Dai, Member and Charkhgard, 2021). When implementing battery storage, optimal energy and power control in grid-connected systems becomes the main concern (Malysz, 2014),(Shi et al., 2017)(Pand, Pand and Kuzle, 2019). Modular storage systems are growing faster than large- scale ones (Irany et al., 2019), which indicates that the mass market of storage should be more frequently analyzed and monitored.

4.3 Thermal Energy Storage Systems

The potential for utilizing thermal energy storage technologies has not been fully used. (Yang et al., 2021) presents the current state of the art of technology and provides a comprehensive review of potential applications. Usage of thermal energy storage is being utilized as large- scale compressed air energy storage, but this application needs suitable geological locations for large underground caverns. (King et al., 2021) presents an overview of CAES potential in India and the UK showing development in finding new possibilities for storage utilization.

A large-scale electrical energy storage alternative to PHS and CAES is liquid air energy

storage, which can enhance its profitability and technology performance in hybrid solutions

with the design of the waste energy recovery sections (Borri et al., 2021). Since solar thermal

systems aren’t still economically feasible, (Gautam and Saini, 2020), presented the techno-

economic potential of these systems together with packed back storage systems.

4.4 Chemical Energy Storage Systems ( hydrogen)

This type of storage system can be used as energy arbitrage and long-term storage, rather than fast response storage. Low efficiencies of 54%, are applicable in hybrid storage systems such as wind-hydrogen storage units (Storage, Energy and Abdi, 2019). Findings show that pumped hydro energy storage is the most cost-effective storage technology and for short-term and medium-term deployment scenarios, followed by compressed air storage and opposed to hydrogen storage (Klumpp, 2016), but for large-scale storage, hydrogen cost-effectiveness is behind compressed air storage.

4.5 Electrical Energy Storage Systems ( Capacitor, Supercapacitor, SMEs Supercapacitors can be used as fast charge or backup systems since they have long cycling life, high power density, and reversibility. These systems are described in detail in (Chang and Hang Hu, 2018). (Wang et al., 2021) summarized materials for flexible supercapacitors provided an overview of strategies for improving their performance and described future aspects of supercapacitors considering high costs at the moment. Study (Miller and Butler, 2021) gives a design approach for every storage application and shows that there is no the best capacitor since every examined capacitor has the best performance for a specific application.

4.6 Hybrid power systems with storage

With the high penetration of photovoltaics in distribution grids in recent years, there have been operational challenges for maintaining frequency stability. Technologies decrease in solar, increases household installations for self-consumption. Home storage systems that store excess electricity generation during the day are making roof-top solars feasible. Decreasing prices in battery technology are boosting economic effects for end-users. Home storage in Germany has grown at more than 50% per year since 2013., which shows a usable storage capacity of about 600 MWh and a total output of more than 200 MW by the end of 2017.

(Kairies et al., 2019). Initial investment costs are still a barrier for wider renewable and storage grid integration. Techno-economic analysis of battery, thermal, and pumped hydro storage is based on the Levelized Cost of electricity (He et al., 2021). This comparison shows that thermal energy storage is the most cost-effective. New research of superconducting magnetic energy storage in wind power generation systems, shows flexibility potential (Xu et al., 2018). A review of different sizing methodologies and capacity optimization for these hybrid systems is given in (Rı, 2012), (He et al., 2021). Battery hybrid systems can be a suitable option for enhancing storage profitability since it was proven that calendar aging of batteries is a major limit instead of cycling aging (Münderlein et al., 2020).

5 An economic analysis of storage technologies

Energy storage advantages are presented in the chapters above. Nevertheless, economic

assessment is important for mitigating wider storage installation and hence wider renewables

grid integration (Zerrahn, Schill, and Kemfert, 2018). (Aguiar and Gupta, 2021) proposed the energy storage insurance contract, which is signed between renewable producers and store owners, promoting the increase of renewables in the market, and provides revenue for storage units in the market. Different flexibility options are analyzed in (Resch et al., 2021) showing techno-economic possibilities of large-scale battery storage for PV grid expansion as opposites to traditional distribution grids. Reviewed storage technologies for load shifting in (Frate, Ferrari, and Desideri, 2019) proved non-feasibility, but for very low charging energy prices promising technologies are: ACAES, ICAES, and Ra-PTES, followed by Br-PTES, PHES, and UPHES.

On the other side, end-users play important role in the energy revolution, as self-consumption increases (Kairies et al., 2019). Case study of the proposed model for optimal dispatching energy storage system as integrated into user-side, (Ding et al., 2021) ensures system's economy and minimizes operational costs. Economic benefits must be maximized for energy systems to be properly utilized. Based on the current storage costs and electricity market policy, installations of energy storage systems on the customer side, cannot gain profits, but can consequently reduce CO2 emissions (Chen, Li, and Li, 2021), which leads to high environmental impact. New research (Schram et al., 2020), (Liu et al., 2021) shows high potential in community energy storage, developed for trading electricity between local households.

When analyzing investment profitability of storage installations, Levelized costs of storage are recently used as a comparison between different technologies (Borri et al., 2021).

Levelized cost of storage 𝐶𝐿𝐶𝑂𝑆 (€/kWh) is the internal average price at which electricity can be sold for the investment's net present value to be zero. This is the sum of the Levelized Cost of electricity discharged 𝐶𝐿𝐶𝑂𝐸 and electricity market price 𝑃𝑒𝑙 (€/kWh) divided with energy storage system efficiency factor 𝜂(input/output of energy storage system). Detailed levelized storage costs assesment is given in (Topalovic et al., 2022).

𝐶𝐿𝐶𝑂𝑆 = 𝐶𝐿𝐶𝑂𝐸 + ^𝑃𝑒𝑙

𝜂 (1)

5.1 Overview of the economic assessment

Further development of energy storage technologies is wildly influenced by economic characteristics. (Li and Decarolis, 2015) used mixed integer programming for examination of the cost-effectiveness of offshore wind coupled to offshore compressed air energy storage.

Other studies not older than 5 years are examined through the research, showing most of the

data is collected from articles and using Levelized cost of storage (Rahman et al., 2020)

(Mostafa et al., 2020). (Parra et al., 2017) used also Levelized cots of storage but, as well two

other complementary techno-economic methods: the Levelized value and profitability. The

main difference between results found in the given literature is the cost variation due to the

proposed assumptions. Depending on the different discharge time, life cycle, efficiency, and

market price, the uniformity of the Levelized cost of storage is reduced. Cost comparison of

three large-scale energy storage technologies ( hydro, compressed air, and hydrogen (power-

to-gas), given in(Klumpp, 2016) uses CAPEX and OPEX for Levelized electricity calculation.

OPEX consists of costs for operating and maintaining installations, but as well as electricity consumed for charging storage, which equals in the end to the Levelized cost of storage. The first economic characterization of offshore compressed air energy storage is given in (Li and Decarolis, 2015). The model is also based on the Levelized Cost of electricity and optimization of the grid-tied cable capacity. (de Boer et al., 2014) analyzed economic consequences of the application of power-to-gas, PHS, and CAES in electricity systems at different wind power penetration levels. They conclude that the application of large-scale energy storage systems reduces costs. These reductions are higher when using storage systems with higher cycle efficiency, higher storage production capacity, or coupling storage to an energy system with a higher wind penetration. Environmental effects for some scenarios resulted in higher fuel use and emissions.

6 Environmental aspects of energy storage

Energy policies are focused on reducing CO2 emissions, shifting towards intermittent renewable power, and maintaining grids stability (European Commission, 2013), but also on the environmental aspect of these technologies. A comprehensive review that integrates both economic and environmental criteria of energy storage is (Rahman et al., 2020). Techno- economic assessment in this paper shows that the Levelized cost of energy decreases with an increase in storage duration. Challenge for electrochemical energy storage wider integration is the disposal of material, besides already issued life cycle. Recycling and disposal costs are usually excluded from Levelized storage costs calculations since there is scarce information from production companies, but the environmental impact of each storage technology is analyzed when considering GHG mitigation (Balali and Stegen, 2021),(Schram et al., 2020).

7 Energy and market policies for ES grid integration

The impact of energy policies in further storage development is evident in (Lai and Locatelli, 2021). Policy mechanism designed to support low-carbon technologies such as CFD – contract for difference is affecting energy storage adoption in the UK and energy storage market. Paper presents mechanisms for promoting energy storage growth: direct subsidies and price floor.

Europe plans to be an emission-free continent by 2050(European Commission, 2019), which

can be ensured by adequate energy policies. In the USA several electricity markets include a

capacity market where energy storage operators can participate and provide additional

revenue(Geske and Green, 2016). This is implemented in Britain as well, but it is questioned

if capacity market rules which include penalties for not delivering electricity, can be a guarantee

for precautionary storage. Simulation model for prosumagers, as seen in (Say, Schill and John,

2020) underlines importance of controlling future growth of prosumagers. Regulators should

promote battery flexibility in energy transition, but investors and power system planners of

large-scale renewable generation should prevent possible prosumagers overinvestment.

8 Conclusion

We are facing dramatic challenges with climate changes, that can be overcome with adequate planning of power systems, installing renewable generation, and flexible operating. Energy storage systems play a key role in providing sustainable and flexible power grids with generation from renewable sources. When grids were regional with a small number of interconnections, pumped hydro plants had one simple regional usage. Today, with new technologies and generation from renewable energy sources, the electricity market needs energy storage more than ever to ensure stability. Considering smart grids and distributed energy sources, prosumagers are new market players, hence storage systems are needed locally as well. Analysis of storage systems shows that we need storage installations in every part of the electricity grids: transmission, distribution, for large- scale, locally beside wind and solar plants and in our homes.

Future development of net-zero emissions by 2050, depends on energy storage systems development as storage technology costs are still a major barrier. Overview of storage technology shows wide research in different systems, but still, PHS, CAES is leading cost- efficient technology for large scale storage. Batteries and flywheels are important for backup and fast response application, hence we conclude that cost for batteries technology will further decrease, especially with the changes in the transport sector and a new paradigm of e-mobility.

The environmental aspect should be analyzed in every cost calculation since costs for

recycling and disposing of batteries are rather omitted in the analyzed literature. Storage

systems should be developed proportionally to the renewable shares in the power systems

and following demand for electric vehicles. The major contribution of this paper is a

comprehensive energy storage review considering technology and feasibility. Analysis shows

the importance of installing higher capacity levels of storage systems in power grids, as a

measure for operating and balancing the future Internal European market. As energy storage

systems are the main source of flexibility in the electricity market, it is expected for the storage

market to rise and balance possible price fluctuations. Hence, future research should focus on

improving operating strategies and market frameworks.

Nomenclature kWh kilowatt-hour MW megawatt MWh megawatt-hour GW gigawatt GWh gigawatt-hour

Abbreviations ACAES

Br-PTES CAES CAPEX COVID-19 CO2 DOE ES EU EVs FESS GHG ICAES IEA Li-ion NTSS OPEX PV PHS PHES Ra-PTES RES UK UPHES USA

Adiabatic CAES

Brayton cycles Pumped Thermal Electricty Storage Compressed Air Energy Storage

Capital Expenditure

Corona Virus Disease 2019.

Carbon dioxide

Global Energy Storage Database Energy Storage

European Union Electric vehicles

Flywheel Energy Storage Green House Emissions Isothermal CAES

International Energy Agency Lithium-ion

National Technology & Engineering Sciences of Sandia Operating Expenses

Photovoltaic

Pumped Hydro Storage

Pumped Hydro Energy Storage

Rankine cycles Pumped Thermal Electricity Storage Renewable Energy Sources

United Kingdom

Underground PHES

United States of America

References

Aguiar, N. and Gupta, V. (2021) ‘An insurance contract design to boost storage participation in the electricity market’, IEEE Transactions on Sustainable Energy, 12(1), pp. 543–552. doi:

10.1109/TSTE.2020.3011052.

Al-hadhrami, L. M. and Alam, M. (2015) ‘Pumped hydro energy storage system : A technological review’, 44, pp. 586–598. doi: 10.1016/j.rser.2014.12.040.

Alimardani, M., Narimani, M. and Member, S. (2021) ‘A New Energy Storage System Configuration to Extend Li-Ion Battery Lifetime for a Household Une nouvelle configuration de système de stockage d ’ énergie pour prolonger la durée de vie de la batterie Li-Ion pour un foyer’, 44(2), pp. 171–178.

Arabkoohsar, A. and Sadi, M. (2021) Flywheel energy storage, Mechanical Energy Storage Technologies. Elsevier Inc. doi: 10.1016/b978-0-12-820023-0.00005-5.

Balali, Y. and Stegen, S. (2021) ‘Review of energy storage systems for vehicles based on technology, environmental impacts, and costs’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 135(February 2020), p. 110185. doi: 10.1016/j.rser.2020.110185.

Barbaros, E., Aydin, I. and Celebioglu, K. (2021) ‘Feasibility of pumped storage hydropower with existing pricing policy in Turkey’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 136(March 2020), p. 110449. doi: 10.1016/j.rser.2020.110449.

Barbour, E. et al. (2016) ‘A review of pumped hydro energy storage development in signi fi cant international electricity markets’, Renewable and Sustainable Energy Reviews. Elsevier, 61, pp. 421–432. doi: 10.1016/j.rser.2016.04.019.

Behabtu, H. A. et al. (2020) ‘A review of energy storage technologies’ application potentials in renewable energy sources grid integration’, Sustainability (Switzerland), 12(24), pp. 1–20. doi:

10.3390/su122410511.

Blakers, A. et al. (2018) ‘Pumped hydro energy storage to support 100 % renewable electricity’, pp.

3672–3675.

de Boer, H. S. et al. (2014) ‘The application of power-to-gas, pumped hydro storage and compressed air energy storage in an electricity system at different wind power penetration levels’, Energy, 72, pp. 360–370. doi: 10.1016/j.energy.2014.05.047.

Borri, E. et al. (2021) ‘A review on liquid air energy storage: History, state of the art and recent developments’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 137(November 2020), p. 110572. doi: 10.1016/j.rser.2020.110572.

Chang, L. and Hang Hu, Y. (2018) Supercapacitors, Comprehensive Energy Systems. doi:

10.1016/B978-0-12-809597-3.00247-9.

Chen, S., Li, Z. and Li, W. (2021) ‘Integrating high share of renewable energy into power system using customer-sited energy storage’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 143(July 2019), p. 110893. doi: 10.1016/j.rser.2021.110893.

Dai, R., Member, S. and Charkhgard, H. (2021) ‘The utilization of shared energy storage in energy systems : a comprehensive review’, 3053(c), pp. 1–8. doi: 10.1109/TSG.2021.3061619.

Dallinger, B. et al. (2019) ‘Socio-economic benefit and profitability analyses of Austrian hydro storage power plants supporting increasing renewable electricity generation in Central Europe’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 107(March), pp. 482–496. doi:

10.1016/j.rser.2019.03.027.

Danila, E. (2015) ‘Ieei 2010’, (January), pp. 1–4. doi: 10.13140/2.1.1564.7040.

Das, C. K. et al. (2018) ‘Overview of energy storage systems in distribution networks: Placement, sizing, operation, and power quality’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 91(November 2016), pp. 1205–1230. doi: 10.1016/j.rser.2018.03.068.

Ding, Y. et al. (2021) ‘Optimal dispatching strategy for user-side integrated energy system considering multiservice of energy storage’, International Journal of Electrical Power & Energy Systems.

Elsevier Ltd, 129(January), p. 106810. doi: 10.1016/j.ijepes.2021.106810.

Dursun, B. and Alboyaci, B. (2010) ‘The contribution of wind-hydro pumped storage systems in meeting Turkey ’ s electric energy demand’, Renewable and Sustainable Energy Reviews.

Elsevier Ltd, 14(7), pp. 1979–1988. doi: 10.1016/j.rser.2010.03.030.

El-batawy, S. A., Morsi, W. G. and Member, S. (2021) ‘Integration of Prosumers with Battery Storage

and Electric Vehicles via Transactive Energy’, 5(c). doi: 10.1109/TPWRD.2021.3060922.

European Commission (2013) ‘The future role and challenges of Energy Storage’, DG ENER Working Paper, pp. 1–36. Available at: http://ec.europa.eu/energy/infrastructure/doc/energy- storage/2013/energy_storage.pdf.

European Commission (2019) ‘The European Green Deal’, European Commission, 53(9), p. 24. doi:

10.1017/CBO9781107415324.004.

Fang, Z. et al. (2020) ‘Progress and challenges of flexible lithium ion batteries’, Journal of Power Sources. Elsevier B.V., 454(January), p. 227932. doi: 10.1016/j.jpowsour.2020.227932.

Fares, R. L. and Webber, M. E. (2018) ‘What are the tradeoffs between battery energy storage cycle life and calendar life in the energy arbitrage application?’, Journal of Energy Storage. Elsevier Ltd, 16, pp. 37–45. doi: 10.1016/j.est.2018.01.002.

Figgener, J. et al. (2020) ‘The development of stationary battery storage systems in Germany – A market review’, Journal of Energy Storage. Elsevier, 29(March), p. 101153. doi:

10.1016/j.est.2019.101153.

Frate, G. F., Ferrari, L. and Desideri, U. (2019) ‘Critical review and economic feasibility analysis of electric energy storage technologies suited for grid scale applications’, E3S Web of Conferences, 137, pp. 1–6. doi: 10.1051/e3sconf/201913701037.

Gautam, A. and Saini, R. P. (2020) ‘A review on technical, applications and economic aspect of packed bed solar thermal energy storage system’, Journal of Energy Storage. Elsevier, 27(August 2019), p. 101046. doi: 10.1016/j.est.2019.101046.

Geske, J. and Green, R. (2016) ‘Optimal storage investment and management under uncertainty’, 2016 IEEE 8th International Power Electronics and Motion Control Conference, IPEMC-ECCE Asia 2016, 41(2), pp. 524–529. doi: 10.1109/IPEMC.2016.7512341.

Global Energy Storage Database, National Technology& Engineering Sciences of Sandia, LLC (NTESS), https://www.sandia.gov/ess-ssl/global-energy-storage-database/, June, 2021 Habibi, M. et al. (2020) ‘An Enhanced Contingency-based Model for Joint Energy and Reserve

Markets Operation by Considering Wind and Energy Storage Systems’, IEEE Transactions on Industrial Informatics, 17(5), pp. 1–1. doi: 10.1109/tii.2020.3009105.

He, Y. et al. (2021) ‘The quantitative techno-economic comparisons and multi-objective capacity optimization of wind-photovoltaic hybrid power system considering different energy storage technologies’, Energy Conversion and Management, 229. doi:

10.1016/j.enconman.2020.113779.

Hunt, J. D. et al. (2020) ‘Existing and new arrangements of pumped-hydro storage plants’, Renewable and Sustainable Energy Reviews, 129(May). doi: 10.1016/j.rser.2020.109914.

IEA (2020) Electricity Market Report, Electricity Market Report. doi: 10.1787/f0aed4e6-en.

India energy outlook report (IEA) (2015) India Energy Outlook, World Energy Outlook Special Report. Available at:

http://www.worldenergyoutlook.org/media/weowebsite/2015/IndiaEnergyOutlook_WEO2015.

pdf.

International Energy Agency (2020) ‘World Energy Outlook 2020 - Event - IEA’, World Energy Outlook 2020 - Event - IEA, pp. 1–25. Available at: https://www.iea.org/events/world-energy-outlook- 2020.

Irany, R. et al. (2019) ‘Energy Storage Monitor’, World Energy Council, pp. 1–32. Available at:

https://www.worldenergy.org/assets/downloads/ESM_Final_Report_05-Nov-2019.pdf.

Irena (2020) Global Renewables Outlook: Energy transformation 2050, International Renewable Energy Agency. Available at: https://www.irena.org/publications/2020/Apr/Global- Renewables-Outlook-2020.

IRENA and CPI (2020), Global Landscape of Renewable Energy Finance, 2020. (2020) GLOBAL LANDSCAPE OF RENEWABLE ENERGY FINANCE 2020.

Javed, M. S. et al. (2020) ‘Hybrid pumped hydro and battery storage for renewable energy based power supply system’, Applied Energy. Elsevier, 257(October 2019), p. 114026. doi:

10.1016/j.apenergy.2019.114026.

Kairies, K. P. et al. (2019) ‘Market and technology development of PV home storage systems in Germany’, Journal of Energy Storage. Elsevier, 23(April), pp. 416–424. doi:

10.1016/j.est.2019.02.023.

Kelly, J. J. and Leahy, P. G. (2020) ‘Optimal investment timing and sizing for battery energy storage systems’, Journal of Energy Storage. Elsevier, 28(January), p. 101272. doi:

10.1016/j.est.2020.101272.

King, M. et al. (2021) ‘Overview of current compressed air energy storage projects and analysis of the potential underground storage capacity in India and the UK’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 139(December 2020), p. 110705. doi:

10.1016/j.rser.2021.110705.

Klumpp, F. (2016) ‘Comparison of pumped hydro , hydrogen storage and compressed air energy storage for integrating high shares of renewable energies — Potential , cost-comparison and ranking’, Journal of Energy Storage. Elsevier Ltd, 8, pp. 119–128. doi:

10.1016/j.est.2016.09.012.

Koohi-Fayegh, S. and Rosen, M. A. (2020) ‘A review of energy storage types, applications and recent developments’, Journal of Energy Storage. Elsevier, 27(July 2019), p. 101047. doi:

10.1016/j.est.2019.101047.

Lai, C. S. and Locatelli, G. (2021) ‘Are energy policies for supporting low-carbon power generation killing energy storage?’, Journal of Cleaner Production. Elsevier Ltd, 280, p. 124626. doi:

10.1016/j.jclepro.2020.124626.

Li, B. and Decarolis, J. F. (2015) ‘A techno-economic assessment of offshore wind coupled to offshore compressed air energy storage’, APPLIED ENERGY. Elsevier Ltd, 155, pp. 315–322. doi:

10.1016/j.apenergy.2015.05.111.

Liu, Jichun et al. (2021) ‘Optimal planning and investment benefit analysis of shared energy storage for electricity retailers’, International Journal of Electrical Power and Energy Systems. Elsevier Ltd, 126(PA), p. 106561. doi: 10.1016/j.ijepes.2020.106561.

Malysz, P. (2014) ‘An Optimal Energy Storage Control Strategy for’, 5(4), pp. 1785–1796.

Martin, N. and Rice, J. (2021) ‘Power outages, climate events and renewable energy: Reviewing energy storage policy and regulatory options for Australia’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 137(November 2020), p. 110617. doi: 10.1016/j.rser.2020.110617.

Mazzoni, S. et al. (2019) ‘Energy storage technologies as techno-economic parameters for master- planning and optimal dispatch in smart multi energy systems’, Applied Energy. Elsevier, 254(August), p. 113682. doi: 10.1016/j.apenergy.2019.113682.

Metz, D. and Saraiva, J. T. (2018) ‘Use of battery storage systems for price arbitrage operations in the 15- and 60-min German intraday markets’, Electric Power Systems Research. Elsevier B.V., 160, pp. 27–36. doi: 10.1016/j.epsr.2018.01.020.

Miao, Y. et al. (2019) ‘Current li-ion battery technologies in electric vehicles and opportunities for advancements’, Energies, 12(6), pp. 1–20. doi: 10.3390/en12061074.

Miller, J. R. and Butler, S. (2021) ‘Storage system design based on equivalent-circuit-model simulations: Comparison of eight different electrochemical capacitor storage systems’, Journal of Power Sources. Elsevier B.V., 491(November 2020), p. 229441. doi:

10.1016/j.jpowsour.2020.229441.

Mohandes, B. et al. (2021) ‘Renewable Energy Management System: Optimum Design & Hourly Dispatch’, IEEE Transactions on Sustainable Energy, pp. 1–1. doi:

10.1109/tste.2021.3058252.

Mostafa, M. H. et al. (2020) ‘Techno-economic assessment of energy storage systems using annualized life cycle cost of storage ( LCCOS ) and levelized cost of energy ( LCOE ) metrics’, Journal of Energy Storage. Elsevier, 29(March), p. 101345. doi: 10.1016/j.est.2020.101345.

Münderlein, J. et al. (2020) ‘Optimization of a hybrid storage system and evaluation of operation strategies’, International Journal of Electrical Power and Energy Systems. Elsevier, 119(December 2019), p. 105887. doi: 10.1016/j.ijepes.2020.105887.

Nazemi, M. et al. (2021) ‘Uncertainty-Aware Deployment of Mobile Energy Storage Systems for Distribution Grid Resilience’, 3053(c), pp. 1–15. doi: 10.1109/TSG.2021.3064312.

Olabi, A. G. et al. (2021) ‘Critical review of energy storage systems’, Energy. Elsevier Ltd, 214, p.

118987. doi: 10.1016/j.energy.2020.118987.

Pand, K., Pand, H. and Kuzle, I. (2019) ‘Electrical Power and Energy Systems Virtual storage plant o ff ering strategy in the day-ahead electricity market’, 104(January 2018), pp. 401–413. doi:

10.1016/j.ijepes.2018.07.006.

Parra, D. et al. (2017) ‘An integrated techno-economic and life cycle environmental assessment of power-to-gas systems’, Applied Energy. Elsevier Ltd, 193, pp. 440–454. doi:

10.1016/j.apenergy.2017.02.063.

Poullikkas, A. (2013) ‘A comparative overview of large-scale battery systems for electricity storage’, Renewable and Sustainable Energy Reviews. Elsevier, 27, pp. 778–788. doi:

10.1016/j.rser.2013.07.017.

Rahman, M. M. et al. (2020) ‘Assessment of energy storage technologies: A review’, Energy Conversion and Management. Elsevier Ltd, 223(May). doi: 10.1016/j.enconman.2020.113295.

Rahman, M. M. et al. (2021) ‘The development of a techno-economic model for the assessment of the cost of flywheel energy storage systems for utility-scale stationary applications’, Sustainable Energy Technologies and Assessments. Elsevier Ltd, 47(June), p. 101382. doi:

10.1016/j.seta.2021.101382.

Resch, M. et al. (2021) ‘Techno-economic Assessment of Flexibility Options Versus Grid Expansion in Distribution Grids’, IEEE Transactions on Power Systems, pp. 1–10. doi:

10.1109/TPWRS.2021.3055457.

Rı, G. J. (2012) ‘Optimal sizing of renewable hybrids energy systems : A review of methodologies’, 86, pp. 1077–1088. doi: 10.1016/j.solener.2011.10.016.

Salama, H. S. and Vokony, I. (2020) ‘Comparison of different electric vehicle integration approaches in presence of photovoltaic and superconducting magnetic energy storage systems’, Journal of Cleaner Production, 260. doi: 10.1016/j.jclepro.2020.121099.

Santos, S. F. et al. (2021) ‘Influence of Battery Energy Storage Systems on Transmission Grid Operation With a Significant Share of Variable Renewable Energy Sources’, IEEE Systems Journal, pp. 1–12. doi: 10.1109/jsyst.2021.3055118.

Say, K., Schill, W. P. and John, M. (2020) ‘Degrees of displacement: The impact of household PV battery prosumage on utility generation and storage’, Applied Energy. Elsevier, 276(June), p.

115466. doi: 10.1016/j.apenergy.2020.115466.

Schram, W. L. et al. (2020) ‘On the Trade-Off between Environmental and Economic Objectives in Community Energy Storage Operational Optimization’, IEEE Transactions on Sustainable Energy, 11(4), pp. 2653–2661. doi: 10.1109/TSTE.2020.2969292.

AL Shaqsi, A. Z., Sopian, K. and Al-Hinai, A. (2020) ‘Review of energy storage services, applications, limitations, and benefits’, Energy Reports. Elsevier Ltd, 6(xxxx), pp. 288–306. doi:

10.1016/j.egyr.2020.07.028.

Shen, Y. et al. (2021) ‘Optimal Dispatch of Regional Integrated Energy System Based on a Generalized Energy Storage Model’, IEEE Access, 9, pp. 1546–1555. doi:

10.1109/ACCESS.2020.3046743.

Shi, J. et al. (2017) ‘Energy management strategy for microgrids including heat pump air-conditioning and hybrid energy storage systems’, 2017(October), pp. 2412–2416. doi:

10.1049/joe.2017.0762.

Soini, M. C., Parra, D. and Patel, M. K. (2020) ‘Does bulk electricity storage assist wind and solar in replacing dispatchable power production?’, Energy Economics. Elsevier B.V, 85, p. 104495.

doi: 10.1016/j.eneco.2019.104495.

Storage, E., Energy, E. and Abdi, H. (2019) ‘Learn more about Energy Storage System Energy Storage Systems Introduction to electrical energy sys- tems THE APPLICATION OF WAYSIDE EN- ERGY STORAGE SYSTEMS TO ELEC-’, in.

Telaretti, E. and Dusonchet, L. (2017) ‘Stationary battery technologies in the U.S.: Development Trends and prospects’, Renewable and Sustainable Energy Reviews. Elsevier, 75(November), pp. 380–392. doi: 10.1016/j.rser.2016.11.003.

Thormann, B., Puchbauer, P. and Kienberger, T. (2021) ‘Analyzing the suitability of flywheel energy storage systems for supplying high-power charging e-mobility use cases’, Journal of Energy Storage. Elsevier Ltd, 39(March), p. 102615. doi: 10.1016/j.est.2021.102615.

Topalovic, Z. et al. (2022) ‘Economics of electric energy storage . The case of Western Balkans’, 238.

doi: 10.1016/j.energy.2021.121669.

Vyas, G. and Dondapati, R. S. (2020) ‘Investigation on the structural behavior of superconducting

magnetic energy storage (SMES) devices’, Journal of Energy Storage. Elsevier, 28(November

2019), p. 101212. doi: 10.1016/j.est.2020.101212.

Wang, Y. et al. (2021) ‘Flexible supercapacitor: Overview and outlooks’, Journal of Energy Storage.

Elsevier Ltd, 42(August), p. 103053. doi: 10.1016/j.est.2021.103053.

Wu, Y. et al. (2021) ‘Portfolio planning of renewable energy with energy storage technologies for different applications from electricity grid’, Applied Energy. Elsevier Ltd, 287(November 2020), p. 116562. doi: 10.1016/j.apenergy.2021.116562.

Xu, Y. et al. (2018) ‘Research on the Application of Superconducting Magnetic Energy Storage in Microgrids for Smoothing Power Fluctuation Caused by Operation Mode Switching’, IEEE Transactions on Applied Superconductivity, 28(4), pp. 10–14. doi:

10.1109/TASC.2018.2808454.

Yang, L. et al. (2021) ‘A comprehensive review on sub-zero temperature cold thermal energy storage materials , technologies , and applications : State of the art and recent developments’, Applied Energy. Elsevier Ltd, (xxxx), p. 116555. doi: 10.1016/j.apenergy.2021.116555.

Yang, Y. et al. (2018) ‘Battery energy storage system size determination in renewable energy systems:

A review’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 91(January), pp. 109–

125. doi: 10.1016/j.rser.2018.03.047.

Zerrahn, A., Schill, W. and Kemfert, C. (2018) ‘On the economics of electrical storage for variable renewable energy sources’, European Economic Review. Elsevier B.V., 108, pp. 259–279. doi:

10.1016/j.euroecorev.2018.07.004.

Zubi, G. et al. (2018) ‘The lithium-ion battery: State of the art and future perspectives’, Renewable and

Sustainable Energy Reviews, 89(March), pp. 292–308. doi: 10.1016/j.rser.2018.03.002.