Global Analysis of Electric Vehicle Charging Infrastructure and Sustainable Energy Sources Solutions

Abstract

Recently, the rapid increase in the adoption of electric vehicles (EVs) has been driven by considerable technological advancements and a growing focus on environmental sustainability. As consumers and governments increasingly recognize EVs as a viable alternative to traditional internal combustion engine vehicles, the demand for a reliable and accessible charging infrastructure has surged. However, establishing a robust network of charging stations is no longer crucial only to fulfill the demands of EV proprietors but also to relieve range anxiety and improve user convenience, thereby facilitating wider EV adoption. This paper provides a comprehensive global analysis of charging station infrastructure, exploring international standards and regulations, various charging modes, the key parameters of leading electric vehicles, and the importance of RE deployment and ES solutions.

1. Introduction

The environmental consequences of Greenhouse Gas (GHG) emissions and growing public awareness of their impact have led to significant transformations in the mobility sector. Conventional transportation, primarily reliant on internal combustion engines (ICEs) [1], remains one of the leading contributors to air pollution and climate change. According to the European Commission, the transportation sector accounts for nearly a quarter of Europe’s total GHG emissions [1,2], prompting several EU nations to implement aggressive policies aimed at reducing emissions through the adoption of EVs and the expansion of the EV charging infrastructure. Similarly, the United States government has reinforced its commitment to reducing carbon emissions by promoting EV adoption and investing in the expansion of charging networks. To achieve these goals, standardization efforts led by the Society of Automotive Engineers (SAE) [3] have been instrumental in ensuring interoperability, safety, and efficiency across the EV industry. These standards regulate various aspects of EV technology, including charging infrastructure [4], battery technology [5], vehicle-to-grid (V2G) [6,7] communication, and safety protocols, thereby addressing key challenges in EV integration and infrastructure development [8]. The widespread adoption of EVs is driving a fundamental shift in transportation, necessitating a robust and well-planned charging infrastructure that accommodates the diverse needs of EV users [9]. Accurate demand prediction for charging stations [10] is a critical step in this process, requiring a thorough analysis of user travel patterns, vehicle ownership trends, and charging behaviors. These insights contribute to the development of predictive models that optimize station placement and scalability, ensuring accessibility and convenience [11]. DC fast-charging stations [12], with their high-power output, are particularly suited for high-traffic areas where rapid turnaround times are essential. In contrast, AC charging stations, which are more cost-effective, are ideal for locations where vehicles remain parked for extended periods, such as residential areas, workplaces, and shopping centers [13]. The strategic differentiation between charging types enhances the user experience by aligning infrastructure development with real-world charging demands [14]. Globally, research on EV charging infrastructure has played a pivotal role in standardizing practices and fostering international cooperation, enabling effective deployment across different regions. When determining optimal charging station locations [15], factors such as geographical and geological conditions must be considered to reduce installation costs and environmental impact [16]. For instance, sun-rich regions present excellent opportunities for solar-powered charging stations [17], while areas with limited renewable energy resources may require hybrid solutions or additional investments in energy infrastructure to ensure sustainable operation [18].

The integration of renewable energy (RE) sources, such as photovoltaic (PV) solar and wind energy, into the charging infrastructure enhances sustainability while reducing operational costs [19] and minimizing reliance on fossil fuels [20]. Additionally, smart charging solutions help optimize energy consumption by scheduling off-peak charging sessions and balancing grid loads, thereby improving overall energy efficiency. Emerging technologies, including V2G [21] and Grid-to-Vehicle (G2V) [22] systems, allow EVs not only to draw power from the grid but also to return surplus energy, contributing to grid stability and enhanced energy utilization.

Beyond technological advancements, public awareness and government policies play a crucial role in accelerating EV adoption. Community engagement, consumer education, and incentive programs—such as subsidies for charging station installations and tax breaks for EV owners—are vital in fostering a supportive ecosystem for sustainable mobility [23]. A thorough analysis of local EV markets, travel patterns, and charging infrastructure requirements is essential to ensure that EV networks are efficiently designed to meet growing demand. A strategic approach, supported by technological innovations, regulatory frameworks, and collaborative efforts among stakeholders, will be key to seamlessly integrating EVs into everyday transportation systems [24].

This paper presents a comprehensive analysis of global EV charging infrastructure and its integration with sustainable energy sources, addressing critical challenges in charging station deployment, energy efficiency, and renewable energy utilization. Unlike previous studies that focus primarily on battery electric vehicle (BEV) charging, this research expands the discussion to include Fuel Cell Electric Vehicles (FCEVs) and their hydrogen refueling infrastructure, offering a comparative perspective on both technologies. Additionally, the study evaluates renewable energy integration, considering solar-powered charging, wind-based grid support, and green hydrogen production for FCEVs. By examining the technical, economic, and environmental implications of various charging solutions, this work provides practical recommendations for optimizing charging station placement, cost efficiency, sustainability, and long-term scalability.

To further highlight the novel contribution of this study, a comparative analysis of recent research in EV charging infrastructure and sustainable energy integration is presented in

Table 1. Comparative analysis of recent EV research.

Study	Focus Area	BEV Charging Infrastructure	FCEV Hydrogen Refueling Infrastructure	Renewable Energy Integration	Comparative Analysis of BEV vs. FCEV Infrastructure	Policy and Deployment Strategies
[25]	Smart Grid Integration	✅	❌	✅	❌	✅
[26]	BEV Fast Charging	✅	❌	✅	❌	❌
[27]	EV Infrastructure Cost Analysis	✅	❌	✅	❌	✅
[28]	Hydrogen Refueling Stations	❌	✅	❌	❌	✅
This Study	Global EV Charging and Sustainable Energy Solutions	✅	✅	✅	✅	✅

.

So, this study aims to bridge these gaps by providing a holistic analysis of both BEV charging stations and the hydrogen refueling infrastructure, comparing their technological challenges, deployment costs, energy efficiency, and sustainability aspects. Furthermore, this work evaluates policy frameworks and investment strategies, offering insights to support governments, industry stakeholders, and researchers in planning and deploying the next-generation EV charging infrastructure.

The rest of the paper is organized as follows. Section 2 elaborates technological EV infrastructure. Section 3 presents various charging modes. The parameters of leading EVs are presented in Section 4. In Section 5, the need for forecasting models to predict EV charging demand is presented. Section 6 presents the charging infrastructure.

Section 7 discusses ES solutions. Section 8 elaborates the essential needs for RE. Section 9 presents the advantages and drawbacks of different sources of renewable energies. The cost analysis of the charging infrastructure is elaborated in Section 10. Section 11 presents future developments in EV charging and sustainable energy integration. Finally, Section 12 is reserved for the conclusion.

2. Technological EV Infrastructure

EVs rely on ES in rechargeable batteries and use electric motors for propulsion. Their origins date back to the 19th century, shortly after the development of electric motors and RBs, but their popularity declined with the mass production of affordable internal combustion engine (ICE) vehicles. Several factors contributed to the dominance of fuel-powered vehicles, including the accessibility of inexpensive fuel, the rising demand for intercity transportation, the economic viability of gasoline-powered cars due to lower costs, the maturity of gasoline vehicle technology, and the efficiency of large-scale production. Additionally, early EVs faced significant challenges such as a limited driving range, a lack of charging infrastructure, and high initial costs, which hindered their widespread adoption. However, advancements in battery technologies, power electronics, and the charging infrastructure have led to a substantial increase in EV adoption despite ongoing challenges related to public charging accessibility and charging times.

Today, EVs are classified into different categories based on their propulsion and ES methods, including battery electric vehicles (BEVs), Fuel Cell Electric Vehicles (FCEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Hybrid Electric Vehicles (HEVs) (see Figure 1).

BEVs rely entirely on large traction batteries that must be charged from an external electrical source [29], whereas FCEVs generate electricity on board using hydrogen fuel cells, producing only water vapor as a byproduct. Unlike BEVs, which depend on lithium-ion battery storage, FCEVs offer advantages such as a longer range and faster refueling times, making them a viable alternative for applications that require extended driving distances and reduced downtime. Given the growing interest in hydrogen-based mobility, this review expands its focus to analyze both the BEV charging infrastructure and hydrogen refueling infrastructure for FCEVs, addressing their respective advantages and challenges, and global adoption trends. FCEVs rely on the hydrogen refueling infrastructure to store and supply hydrogen, which is converted into electricity through a fuel cell stack to power the vehicle. Unlike battery electric vehicles (BEVs), which depend on charging stations, FCEVs require hydrogen refueling stations equipped with high-pressure hydrogen storage tanks, compressors, and dispensers to efficiently deliver hydrogen to vehicles at 700 bar (for light-duty vehicles) or 350 bar (for heavy-duty vehicles). Compared to BEV charging, hydrogen refueling is significantly faster, with refueling times typically ranging from 3 to 5 min, making FCEVs an attractive solution for long-haul transportation, commercial fleets, and high-usage applications [30].

The deployment of hydrogen refueling stations presents several infrastructure challenges, including high initial investment costs, complex storage and transportation logistics, and limited global availability. Establishing an HRS requires specialized safety protocols, as hydrogen is a highly flammable gas that must be stored and handled under strict International Organization for Standardization (ISO) and Society of Automative Engineers (SAE) standards, such as SAE J2601 for refueling procedures and ISO 17268 for hydrogen fueling connectors. Additionally, the efficiency and sustainability of hydrogen refueling stations depend on the source of hydrogen production. While most hydrogen today is derived from steam methane reforming, which produces CO₂ emissions, the transition toward green hydrogen production through electrolysis using renewable energy is essential for ensuring carbon-neutral FCEV adoption. Globally, leading countries such as Japan, South Korea, Germany, and the United States (California) have invested heavily in hydrogen infrastructure development, with initiatives aimed at expanding hydrogen corridors along major transportation routes. However, the relatively low number of refueling stations compared to BEV charging networks remains a critical barrier to widespread FCEV adoption. Future advancements in hydrogen storage, distribution, and electrolysis efficiency, alongside government incentives and public–private partnerships, will be crucial for the scalability and viability of hydrogen-based transportation [31]. While BEVs continue to dominate passenger vehicle markets due to their established charging network and improving battery technologies, FCEVs remain an essential part of the clean mobility ecosystem, particularly for heavy-duty transport, commercial fleets, and long-haul applications where battery-based solutions may be less practical due to weight and charging constraints.

In contrast, PHEVs combine a reduced-size battery pack with an ICE [32], allowing them to operate in electric mode for shorter trips while switching to fuel-based propulsion for longer distances. HEVs, on the other hand, cannot be charged via external power sources and instead rely on regenerative braking and the ICE to recharge their batteries [33]. As BEVs and FCEVs gain traction, the establishment of a robust and scalable energy infrastructure is critical to their widespread adoption. Since BEVs depend solely on battery storage, their charging systems must be efficient, reliable, compact, cost-effective, and lightweight, while FCEVs require a dedicated hydrogen refueling network with high-pressure storage and dispensing systems. To improve the efficiency and feasibility of BEV charging, advancements in battery chemistry, state-of-charge (SOC) and state-of-health monitoring, thermal management, and fast-changing technologies are essential to reduce charging durations and enhance energy density. Similarly, hydrogen infrastructure development requires significant investment in hydrogen production, storage, and distribution, particularly through green hydrogen derived from renewable sources. The continued expansion of both the BEV and FCEV infrastructure will play a crucial role in the decarbonization of transportation, enabling a sustainable transition to electrified mobility while balancing energy efficiency, cost, and environmental impact.

Figure 1. Different electric vehicle categories [34,35,36,37].

Figure 1. Different electric vehicle categories [34,35,36,37].

2.1. EV Charging Standards

EV charging standards are designed to ensure compatibility and efficiency across different regions and technologies. In Europe, the International Electrotechnical Commission (IEC) standards [38] are predominantly adopted, including the IEC 62196-2 for the Type 2 connectors used for AC charging [39] and the IEC 62196-3 for the Type 1 CCS Combo 2 connectors used for DC fast charging [40]. This standardization helps streamline charging infrastructure across the continent and other regions that follow similar practices.

In the United States, EV charging standards are primarily governed by the SAE and the Institute of Electrical and Electronics Engineers [41]. The SAE J1772 standard covers the Type 1 connectors used for AC charging, while the SAE J1772 [42] combined with CCS (Combo 1) supports both AC and DC fast charging [43]. This dual-standard approach allows for broad compatibility with various vehicles and charging stations. Japan has adopted the CHAdeMO standard, which is specifically designed for DC fast charging and is widely used across the country. The CHAdeMO protocol supports rapid charging and is also available in other regions, though it is most prevalent in Japan [44]. China follows the Guobiao (GB) standard for EV charging, with the GB/T 20234 connector accommodating both AC and DC fast charging. This standard, tailored to meet local requirements and infrastructure, helps integrate China’s growing EV market with its unique charging needs.

These regional standards reflect the diverse approaches to EV charging infrastructure, each tailored to local requirements and technological developments, while also striving for interoperability where possible [45].

The evolution of EV charging standards is crucial for ensuring interoperability, efficiency, and scalability across global charging networks. While established standards such as SAE J1772, IEC 62196, CCS (Combined Charging System), CHAdeMO, and GB/T have provided a foundation for standardization, ongoing technological advancements and regulatory updates continue to shape the landscape. One of the most significant developments is the emergence of the Tesla North American Charging Standard, which has been recently adopted by major automakers like Ford, GM, and Rivian, prompting discussions about its potential to become the new dominant standard in North America. This shift has sparked controversy, as some industry players express concerns over the transition costs and the compatibility of legacy charging infrastructure with NACS.

Another key area of development is ultra-fast-charging technologies, with high-power chargers exceeding 350 kW, enabling faster charging times comparable to traditional refueling. However, these advancements introduce challenges related to battery thermal management, grid stability, and increased electricity demand. Efforts to integrate vehicle-to-grid and bidirectional charging into existing standards are also progressing, allowing EVs to act as ES assets, supporting grid flexibility. Despite these advancements, global standardization remains fragmented, with regional differences in connector types, power levels, and communication protocols hindering universal compatibility.

Additionally, concerns regarding cybersecurity risks in smart charging networks and the interoperability of different charging providers pose ongoing challenges. The push for wireless charging technology, although promising, still faces hurdles related to efficiency losses and high implementation costs. Looking ahead, policymakers, automakers, and infrastructure developers must work collaboratively to address these challenges, ensuring that EV charging standards remain future-proof, widely adopted, and accessible to all users.

2.2. Standards of Charging Connectors

EV charging connectors vary by region and the type of charging they support, reflecting the global diversity in EV infrastructure. In North America, the Type 1 (SAE J1772) [36,37] connector is widely used for Level 1 and Level 2 AC charging, while the CCS Combo 1 integrates both AC and DC fast charging capabilities. In Europe, the Type 2 (Mennekes) connector [46], compliant with the IEC 62196-2 standard, is the norm for Level 1 and Level 2 AC charging, and the Type 2 CCS Combo 2 [47] supports DC fast charging. Japan employs the CHAdeMO [48] standard for DC fast charging, which is also available in other regions. In China, the GB/T standard accommodates both AC and DC fast charging. Tesla uses a proprietary connector in North America and Europe for both AC and its high-speed Supercharger network. Each connector type is tailored to regional standards and charging needs, ensuring compatibility and efficiency in the expanding global EV market.

Charging connectors vary by region and standard, each supporting different types of charging. In North America, the Type 1 (SAE J1772) connector is used for AC charging, while it also supports DC fast charging. Type 2 (Mennekes) is the standard connector for AC charging in Europe, Asia, and Australia, adhering to IEC 62196-2. For DC fast charging in these regions, the Type 1 CCS Combo 2 is utilized, following the IEC 62196-3 standard. In North America, the CCS Combo 1 combines SAE J1772 and CCS standards to support both AC and DC fast charging. The CHAdeMO connector, primarily used in Japan but available globally, supports DC fast charging and adheres to the CHAdeMO standard. In China, the GB/T connector [49], which complies with the GB/T 20234 standard, is used for both AC and DC fast charging. Lastly, Tesla employs a proprietary connector in North America and Europe, accommodating both AC and DC Supercharger charging [50,51,52], as shown in

Table 2. Standards of charging connectors [53].

SAE J1772 Type 1	IEC 62196-2 Type 2	SAE J1772 CCS/Combo 1	IEC 62196-3 CCS/Combo 2
USA/Japan	Europe/China	USA	Europe
AC charging	AC charging	DC fast charging/AC charging	DC fast charging/AC charging
GB/T BB.20234.3	CHA DE MO	GB/T Type 2 20234.2	Tesla
China	China	China	North USA/Europe
DC charging	DC charging	AC charging	AC and DC charging

.

2.3. EV Charging Technologies

Battery charging technologies are classified into conductive charging, wireless charging, and battery swapping, as showed in Figure 2.

The most frequent charging type is conductive [55,56]. It employs a conductor to transfer power, supported by both on-board and off-board chargers [57]. On-board chargers are housed within EVs and are used for slow charging, whereas off-board chargers, situated at fixed points external to EVs, offer fast charging capabilities [58]. Currently, conductive charging predominates and encompasses various modes. The IEC 62196 standard defines four charging modes based on charging types, voltage, and current levels. Mode 1, directly connecting an EV to a wall plug, faces safety challenges in some regions. Mode 2, typically found in private homes or offices, provides slow charging, while Mode 3, a semi-fast AC charging method in EV charging stations, meets moderate speed demands. Mode 4, a DC fast-charging option primarily used commercially, significantly reduces charging times but requires specialized infrastructure [59].

Conductive chargers, which provide electrical power to recharge EV batteries, are categorized as either on-board or off-board. On-board chargers, which perform the AC to DC conversion within the vehicle, are limited by their size and relatively low power output. This setup may enable the use of the traction energy conversion system for battery charging.

In Figure 3, an on-board charging system for an electric vehicle involves various essential components that work together to convert power from an external source into a suitable form for charging the vehicle’s battery pack. The process begins with the power supply, which can be either a single-phase or three-phase AC supply at Level 2, being regulated by a protection unit that ensures the safety of the system by mitigating electrical issues such as overvoltage or overcurrent. The AC power then passes through an EMI filter, which reduces electromagnetic interference to ensure that the charging system does not affect the operation of other nearby electronic equipment. Following this, the power factor correction (PFC) unit optimizes the power factor, thereby enhancing the efficiency of the power transfer and minimizing the reactive power absorbed from the network. The DC/DC inverter then takes the AC power, rectifies it, and converts it into a DC output that is suitable for charging the battery. Within the EV, the BMS plays a critical role in managing the charging process, continuously monitoring parameters such as the voltage, current, and temperature to secure the security and efficiency of the battery pack during charging. The vehicle also includes a dedicated protection unit to safeguard the battery system against possible electrical faults and excessive currents that could occur during the charging cycle. This integrated on-board system ensures that power is safely and efficiently converted and managed, providing the EV with the energy needed while maintaining high safety standards throughout the charging process.

In contrast, off-board chargers are DC chargers that offer higher output power and greater flexibility in the power supply. Conductive charging stations are classified into three levels based on their power output: Level 1, Level 2, and DC fast chargers [61,62].

As shown in Figure 4, an off-board charging station for an EV consists of several key components that facilitate the safe and efficient transfer of power from an external source to the vehicle’s battery pack. The charging process begins with a protection unit, which ensures safety by preventing issues such as overcurrent and overvoltage. Power from the external supply then passes through an EMI filter, which suppresses electromagnetic interference delivered during the charging process to maintain compliance with electromagnetic standards and avoid interference with nearby devices. A PFC circuit is then adopted to optimize the power factor, enhancing energy efficiency by minimizing reactive power and ensuring a stable power draw from the grid. After this, the DC/DC converts the AC power to the required DC voltage and current, which is then sent to the vehicle for charging. Within the EV, the battery BMS monitors and manages the charging process by controlling variables like voltage, current, and temperature, thereby ensuring the battery charges safely and effectively. Additionally, a protection unit inside the vehicle provides further safety by safeguarding the battery system against electrical faults and overcurrent. This coordinated operation of the off-board charging station and the in-vehicle systems enables reliable and efficient battery charging.

The charging time equations for on-board and off-board charging systems differ mainly due to the charging power capacity and system efficiency. Here are the equations for both types of charging:

$$t_{\mathit{\text{on-board}}}={\displaystyle \frac{E_{req}}{{\eta }_{\mathit{\text{on-board}}}\ast P_{\mathit{\text{on-board}}}}}$$

(1)

$$t_{\mathit{\text{off-board}}}={\displaystyle \frac{E_{req}}{{\eta }_{\mathit{\text{off-board}}}\ast P_{\mathit{\text{off-board}}}}}$$

(2)

where the following meaning applies:

• t_on-board: Charging time for on-board charging (hours);
• t_off-board: Charging time for on-board charging (hours);
• E_req: Energy required to charge the battery (kWh);
• P_on-board: Charging power provided by the on-board charger (kW);
• P_off-board: Charging power provided by the off-board charger (kW);
• η_{on-board/off-board}: Efficiency of the on-board/off-board charging system.

The charging time of an FCEV depends on the available power sources, which include the on-board charger and the fuel cell, which can be expressed as:

$$t={\displaystyle \frac{E_{req}}{(P_{OnBoard}+P_{FuelCell}\times {\eta }_{FuelCell})\times {\eta }_{OnBoard}}}$$

(3)

where P_FuelCell and η_FuelCell represent, respectively, the FC power and efficiency.

Inductive (wireless) charging, utilizing electromagnetic fields to transfer power to EV batteries, eliminates the need for physical connections. This charging strategy comes in two types: stationary charging, which happens when the EV is parked, and dynamic charging, which takes place while the EV is moving, with a charging material embedded in the road. Inductive charging presents a promising solution to the problem of varying charging ports, which differ in type, shape, and size across countries and EV manufacturers. By adopting this approach, all EVs can be charged by applying a standardized infrastructure, eliminating the demand for conventional cables. Additionally, this technique offers further advantages, like integrating the charging device into the ground, reducing the risk of theft or accidental problems caused by careless drivers. The lack of physical contact between the charging station and the EV also guarantees security from electric shock risks [63,64]. Despite its convenience, this method suffers from drawbacks such as high power loss, low efficiency, and limited energy transfer capacity.

Battery swapping (BS) may serve as a viable alternative for fleets of electric taxis, allowing drivers to swiftly exchange depleted batteries for completely loaded ones at dedicated BSSs [65,66,67]. Key information includes the vehicle’s location in the station, requests for a new battery, and proper procedures for removing and attaching batteries, along with details about the model of battery and the daily exchange count at each station [68]. Possible points for BSSs have been examined in [69]. This method offers a quick alternative to ensure vehicles are fully charged, potentially taking less time than traditional cable charging.

Service providers handle all maintenance concerns, alleviating driver worries about battery life and upkeep. However, a major drawback is the lack of standardization between battery types, making this service largely specific to certain EV models or brands. Swappable batteries typically belong to energy companies, contributing to potential reductions in EV sticker prices.

Furthermore, the infrastructure for EV charging is categorized into three types: distributed infrastructure, i.e., small charging points located at home or workplaces, connected to the grid with added functionality for vehicle-to-grid; fast-charging infrastructure, i.e., charging stations utilizing high power rates without vehicle-to-grid functionality; and BS infrastructure, i.e., stations with numerous loaded batteries and the capability to recharge them centrally. Consumer perceptions of BS technology, particularly regarding its risks and benefits, will influence its future implementation [70].

3. Various Charging Modes

There are various charging modes that use either AC or DC fast chargers [71,72]. This section delves into the intricacies of these charging modes, shedding light on factors such as charging times, matching with different EV models, and user experience. The aim of this section is to generate a comprehensive overview of the expanding EV charging landscape and highlight the recent advancements shaping the future of electric mobility. As detailed in

Table 3. Charging type, power, voltage, maximum current, charging time, and efficiency [73,74].

Charging Type	Level	Power	Voltage	Maximum Current	Charging Time	Efficiency
Conductive (AC)	Level 1	Up to 1.9 kW	120 V AC	16 A	8–12 h	85–90%
	Level 2	Up to 22 kW	240 V AC	32–80 A	3–8 h	90–95%
	Level 3	Up to 43 kW	400 V AC	63–125 A	30 min to 1 h	95% and above
Conductive (DC)	Level 4	Up to 350 kW	200–1000 V DC	200–500 A	20–40 min	95% and above
Inductive	-	Up to 22 kW	240 V AC	32 A	Similar to AC	90–95%
Swapping	-	System-dependent	-	-	Few minutes	Variable

, this section includes data on different EV charging levels, voltage, maximum current, power, efficiency, and some international guidelines to consider when setting up EV charging stations.

Charging systems for electric vehicles vary widely in capabilities and efficiency. Conductive charging [75], whether AC or DC, offers different levels of power and voltage to accommodate various needs. Level 1 AC charging operates at 120V AC with up to 1.9 kW power, suitable for overnight charging with an efficiency of 85–90%. Level 2 increases both power (up to 22 kW) and voltage (240V AC), capable of charging in 3–8 h with higher efficiency ranging from 90–95%. Level 3 DC charging utilizes 400V AC and delivers up to 43 kW, significantly reducing charging time to 30 min to 1 h with efficiency above 95%. DC Level 4 charging achieves even higher power levels (up to 350 kW) using 200–1000V DC, ideal for rapid charging in 20–40 min with superb efficiency. Inductive charging [76,77,78], operating similarly to AC Level 2, provides convenience without direct contact but with slightly lower efficiency at 90–95%. Swapping systems, though system-dependent and quick (a few minutes), offer variable details and are less common. Each method caters to different charging needs, balancing speeds, convenience levels, and energy efficiency in the electric vehicle infrastructure [79].

4. Parameters of Leading EVs

Table 4. Parameters of leading electric vehicles (level, voltage (V), current (A), power (KW)) [80,81,82,83,84,85,86,87,88].

Model	Level	Voltage (V)	Current (A)	Power (kW)
Hyundai	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 32	Up to 7.2
	Level 3	400	Up to 250	Up to 100
Tesla Model 3	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 48	Up to 11.5
	Level 3	400 to 800	Up to 500	Up to 250
Mini Electric (Mini Cooper SE)	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 32	Up to 7.4
	Level 3	400	Up to 125	Up to 50
Hyundai Ioniq	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 32	Up to 7.2
	Level 3	400 to 800	Up to 500	Up 150
Ford Mustang: Mach-E	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 48	Up to 11
	Level 3	400	Up to 375	Up to 150
BMW i4	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 48	Up to 11
	Level 3	400 to 800	Up to 500	Up to 200
Kia EV6	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 48	Up to 11
	Level 3	400 to 800	Up to 500	Up 350
Porsche Taycan	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 80	Up to 19.2
	Level 3	800	Up to 650	Up to 270
Nissan Leaf	Level 1 (DC)	120	12	Up to 2.4
	Level 2 (AC)	240	Up to 30	Up to 6.6
	Level 3	400	Up to 125	Up to 50

provides an overview of the key electrical parameters for some of the leading EVs currently available. It includes the model, power level, voltage, current, and power output for each vehicle, offering insights into their electrical performance and efficiency. These parameters help highlight the differences in energy consumption and power capabilities, which are essential for understanding the driving range, acceleration, and overall energy utilization of these EVs. The data reflect various vehicle types, from high-performance sports cars to more energy-efficient everyday models, showcasing the diversity of electric mobility options on the market today.

Hyundai supports Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it can handle up to 7.2 kW with a current of 32 amps. With Level 3 DC fast charging, it supports up to 100 kW. The Tesla Model 3 provides Level 1 DC charging at up to 2.4 kW with a current of 12 amps. Its Level 2 AC charging goes up to 11.5 kW with a current of 48 amps. For Level 3 DC fast charging, it can manage up to 250 kW. The Mini Electric (Mini Cooper SE) offers Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it supports up to 7.4 kW with a current of 32 amps. At Level 3, it can handle up to 50 kW. The Hyundai Ioniq supports Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it provides up to 7.2 kW with a current of 32 amps. With Level 3 DC fast charging, it can manage up to 150 kW. The Ford Mustang Mach-E offers Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it supports up to 11 kW with a current of 48 amps. Its Level 3 DC fast charging can handle up to 150 kW. The BMW i4 supports Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it offers up to 11 kW with a current of 48 amps. At Level 3, it can manage up to 200 kW. Kia EV6 provides Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it supports up to 11 kW with a current of 48 amps. Its Level 3 DC fast charging can handle up to 350 kW. The Porsche Taycan offers Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it supports up to 19.2 kW with a current of 80 amps. At Level 3, it can manage up to 270 kW. The Nissan Leaf supports Level 1 DC charging at up to 2.4 kW with a current of 12 amps. For Level 2 AC charging, it provides up to 6.6 kW with a current of 30 amps. With Level 3 DC fast charging, it can handle up to 50 kW.

5. Need for Forecasting Models to Predict EV Charging Demand

As the penetration rate of EVs rises, it is essential to address potential challenges associated with their operations, such as voltage fluctuations and increased pressure on grid systems from transformers and line saturations (L Wang, Z Qin (2021), SA Assadi, H Matsumoto (2019)) [89,90]. Additionally, a reduced number of charging points can cause driving range anxiety among users concerned about having enough range to reach their destination as well as worries about charging times compared to traditional refueling. The mismatch between demand and the accessibility of charging points, along with poorly planned deployments, can result in wasted resources, such as underutilized charging points, and can limit the integration of EVs. Thus, the reliable predicting of EV charging need and strategies of optimization for charging station implementation are vital for encouraging broader EV use.

To ensure the optimal placement and sizing of charging stations, accurate power demand modeling is essential. The total power demand, P_demand, can be estimated as:

$$P_{demand}=n\ast E_{av}$$

(4)

where n is the number of EVs, and E_av is the average energy required per vehicle. This formula estimates the total energy demand required to charge EVs, but it is overly simplistic because it does not consider time dependency.

Such models are crucial for mitigating grid stress and ensuring user satisfaction.

The performance of EV charging need models largely depends on accurately identifying their inputs. Unlike conventional (ICE) vehicles, EVs introduce more complex driving behaviors, including recharging duration, initial SOC, and the timing of charging events. There is insufficient practical understanding of these factors (MS Mastoi, S Zhuang, HM Munir, M Haris, M Hassan, 2023) [91]. The charging need and its distribution are random, influenced by various factors such as land use, infrastructure, and weather conditions. Consequently, selecting the relevant parameters to reinforce EV charging needs and distribution models is challenging due to the uncertainty involved.

Historically, data analysis has been recognized as a valuable tool for enhancing the capability and accuracy of EV charging need tracking by revealing trends and patterns in EV usage. However, in the US, there is a lack of sufficient data, largely because EVs are still emerging in the market, and even basic data collection can be costly due to privacy concerns. To address the gap in real-world data, researchers have utilized supplementary data sources, which have proven effective for specific issues. A review of the literature identifies three main categories of these supplementary data sources (see

Table 5. Data sources for EV charging demand forecasting and their applications.

Data Sources/References	Description
Survey data (e.g., household travel surveys, GPS-based surveys) [92,93]	The assessment of the relative precision of spatiotemporal data obtained from passive sources, using suitable synthetic ground truth (SGT), is still in its early phases. Additional research into positional and temporal accuracy with reliable ground truth is essential for making informed decisions based on passive data. The study applies an accuracy assessment framework to evaluate human mobility patterns derived from GPS, call detail records, and GSM data. It uses outputs from an agent-based simulation platform, SGT, and generates synthetic data while accounting for positional disturbances. The framework compares mobility information such as activity location, departure time, and trajectory distance from the synthetic data to SGT to assess accuracy at both disaggregated and aggregated levels.
Traffic flow volume [94,95]	The widespread presence of traffic lights in urban areas often leads to fluctuations in traffic patterns and energy consumption among vehicles. These variations in speed can significantly impact the energy efficiency of EVs. This research addresses the impact of traffic lights on the energy efficiency of EVs by introducing a Multi-Intersections-Based Eco-Approach and Departure strategy (M-EAD). The M-EAD strategy enhances urban mobility through two key stages: optimizing green signal windows to minimize travel delays, and refining speed trajectories using an iterative dynamic programming algorithm. The aim is to reduce energy consumption and battery wear by identifying the optimal speed for EVs in urban environments
Simulation data [96,97]	The review analyzed 26 unique city logistics solutions using several simulation techniques, such as system dynamics, discrete event simulation, hybrid modeling, and traffic simulation. However, it either omits “traffic simulation” as a separate category or fails to categorize city logistics studies according to the specific traffic simulation approaches employed (micro, meso, or macro). The paper reviewed 16 research studies, of which 6 employed micro, meso, or macro traffic simulation. Nevertheless, this research lacked a systematic approach and did not outline the article selection criteria. Consequently, this research is the first to systematically review research at the intersection of traffic simulation and city logistics, categorizing city logistics papers according to the microscopic, mesoscopic, and macroscopic traffic models utilized. Given the close relationship between urban freight transport and last-mile delivery (LMD), the authors specifically focused on LMD in their examination.

).

These articles provide a range of perspectives and methodologies for studying the various aspects of electric vehicles using different types of data.

The existing data sources are inadequate for independently modeling EV charging demand due to their limited representativity from short survey periods. As previously noted, the driving behaviors of conventional ICE vehicles differ significantly from those of EVs. Thus, simulated outcomes may not accurately capture real-world scenarios, particularly concerning the uncertainties surrounding SOC fluctuations during trips.

Models for EV charging need have been adopted using traffic strategy (Jiang, H Bian, Q Ren (2024), S Tang, Y Mu (2024)) [98,99] and through heuristic algorithms or simulation approaches (E Rodríguez-Esparza. (2024), A Kumar, R Kumar, (2024)) [100,101]. These studies serve as valuable prototypes for identifying regions suitable for deploying charging stations using existing techniques. However, there is an urgent need for effective methods to pinpoint specific candidate sites within these identified zones. The fast advancement of EV technology and the growing adoption of EVs heighten the urgency of this need.

6. Charging Infrastructure

Despite the ongoing global adoption of electric cars, prioritizing their use remains challenging due to a lack of charging infrastructure [102,103]. To address this issue, more charging stations should be installed in public areas, and the public needs to be informed about eco-friendly transportation options. A comprehensive plan, including a geographical assessment and site planning, is necessary to create accessible charging facilities. The rising popularity of EVs has led to various beneficial applications across different sectors. The increasing demand for charging due to the extensive usage of EVs poses significant issues to the network, a phenomenon known as electric marketing [104]. Unlike traditional loads, EVs feature battery storage, which allows them to contribute to the energy trading market by offering additional services, like V2G capabilities. The surge in EV numbers has highlighted the connection between power delivery and has sparked interest in research and development within both the electrical engineering and transportation sectors [105,106]. However, inadequate preparation for charging stations could lead to transmission issues, including increased energy losses and poor voltage quality. A major complication is organizing the wiring for charging to ensure the distribution system operates safely and reliably. Moreover, the electricity demand may soon surpass the current capacity of the electrical grid. Integrating RE sources like PV and wind energy could generate a viable and environmentally friendly solution [107].

7. Essential Need for RE

This part highlights the urgent demand to adopt RE sources to power the growing number of EVs and address the limitations of conventional electricity infrastructures. Major sources of CO2 emissions include power plants and mobility-dependent industries [108]. The dangers posed to people and the environment together have become unacceptable. Using clean energy sources can mitigate climate change impacts while also protecting the natural world [109,110]. However, the effectiveness of RE is heavily dependent on the surrounding environment, and a key drawback is the variability and unpredictability of renewable energy output [111]. This significant environmental impact is central to the current paradigm shift. Solar and wind energy and biofuels are emerging as powerful allies in reducing CO2 emissions and steering us toward a cleaner, greener future [112].

The contribution of RE to the total energy consumption in EV charging networks can be quantified using the following equation:

$$C_{RE}={\displaystyle \frac{E_{RE}}{E_t}}\ast 100$$

(5)

where E_RE is the energy provided by renewable sources, and E_t is the total energy consumed. Maximizing C_RE is pivotal for achieving sustainability goals and reducing carbon emissions.

Installing EV charging stations generated by RE is crucial for slowing global warming, reducing air pollution, and enhancing ecological resilience [113]. Integrating EVs into the network is considered an alternative to these challenges.

The integration of renewable energy into EV charging infrastructure requires careful grid load analysis. The total grid load G_L(t) can be expressed as follows:

$$G_L(t)={\displaystyle \sum _{i=1}^n\frac{P_i}{U_i}}$$

(6)

where P_i is the power drawn by each EV, and U_i represents the respective voltage level. This formulation helps in designing systems that balance load demands and renewable energy contributions effectively

By using RE to power EVs, we can address the issue of uneven green power usage [114,115]. Additionally, this setup helps store excess electricity generated from renewables, preventing a reduction in these energy sources. The electrical grid can be adapted to incorporate sustainable energy sources, EV batteries, and interconnected grids [116,117,118,119,120,121,122,123]. EVs are expected to positively impact the economic growth of the RE sector. Ensuring adequate electricity storage among clean energy sources and EVs is crucial for making both more efficient and sustainable. However, the intermittence of RE sources complicates the reliability needed for EV charging [124]. Advanced technology, such as enhanced battery storage, can help in reducing the variability of RE, providing a consistent and stable energy delivery [125,126]. The use of intelligent technology further enhances this interaction by allowing the charging infrastructure to adapt dynamically to fluctuating energy inputs via online monitoring, resilient control management, and adjustable energy distribution networks [127]. As a result, the charging process becomes more efficient, maximizing energy use while minimizing waste [128]. In addition to the environmental gains, the fiscal advantages of adopting RE for EV charging stations are becoming increasingly apparent [129]. This part explores the potential cost savings associated with RE sources, highlighting the long-term feasibility of this approach. Transitioning to RE not only aligns with worldwide environmental goals but also ensures the economic sustainability of the EV ecosystem. Essentially, this section advocates for a shift in paradigm, moving away from conventional energy models towards a more compatible integration of EV and the limitless power of nature. As we navigate the complex terrain of the energy transition, incorporating RE into EV charging infrastructure is not merely a preference but a crucial move towards a more eco-friendly future.

8. Advantages and Drawbacks of Different Sources of Renewable Energies

Renewable energy sources each come with their own merits and demerits. Hydropower, which holds a global share of 43.39%, is abundant in nature and helps address emission issues, promoting increased longevity and significant energy output. However, it can lead to the migration of inhabitants, disrupt aquatic species, cause erosion, and increase flood risks, potentially harming wildlife ecosystems [130]. Wind energy, accounting for 25% of the market, benefits from advanced technology and convenient construction on both land and sea, offering extensive capacity. On the downside, it can result in bird fatalities, require large land areas, and be vulnerable to natural disasters [131,132,133]. PV energy, also making up 25% of the global share, boasts advanced technology, simple installation, low maintenance, and increased longevity. However, it creates noise, can harm soil, requires significant land area, and has varying efficiency, along with high displacement costs. Finally, solar thermal energy, with a minimal global share of 0.25%, is more efficient than some alternatives, operates without interruption, and has a robust ES capability. Its drawbacks include potential impacts from molten salt processes, effects on bird populations, high installation and capital costs, and a less favorable environment. Overall, while these renewable sources offer significant benefits, they also pose various challenges that need to be addressed [134,135].

9. Energy Storage Solutions

One drawback of RE sources is that supply electricity must be integrated right away or delivered to the network to avoid waste. To address this issue, experts have suggested the use of stationary battery backups and fast-charging devices [136,137]. ES enhances the performance of EV charging by ensuring satisfactory energy is available during emergencies.

The SOC is a critical parameter in battery management systems, reflecting the current energy level of the battery relative to its capacity. It evolves according to the equation:

$$SOC(t)=SOC(t_0)+{\displaystyle \frac{{\displaystyle \underset{t_0}{\overset{T}{\int }}I(t)dt}}{Q_{\max }}}$$

(7)

where SOC(t₀) represents the initial charge state, I(t) is the current over time, and Q_max denotes the battery’s maximum capacity. Accurate SOC estimation ensures efficient energy utilization and extends battery life.

ES systems are categorized based on their mode of storing energy, each with distinct characteristics. Physical ES includes inflated hydro storage, which offers a compact energy density and is suitable for long-duration applications, featuring a rapid charging rate [138]. In contrast, chemical ES involves batteries, which provide a higher energy density but are typically used for shorter-duration applications. Electromagnetic storage options, such as supercapacitors, also deliver a high-power density and are designed for long-term use, with fast charging and discharging rates. Magnetic ES shares similar long-run capabilities, emphasizing efficient energy management. Electrochemical ES is primarily governed by lithium-ion batteries, which account for 76% of the total installed capacity, followed by Na2S (13%), lead (7%), and redox flow batteries (3%) [139]. Nickel–metal hydride (Ni-MH) batteries offer advantages like higher efficiency and easier recyclability compared to lithium-ion batteries.

While lithium-ion batteries remain the dominant ES solution for EVs, emerging technologies like Zinc-ion and Sodium-ion (Na-ion) batteries are gaining attention as cost-effective, sustainable alternatives. Zn-ion batteries, with their abundant raw materials, non-flammable electrolytes, and lower environmental impact, offer enhanced safety and long cycle life, making them ideal for stationary ES rather than EV applications due to their lower energy density. Meanwhile, Na-ion batteries, benefiting from widely available sodium resources, present a promising alternative for EVs and grid storage, reducing dependence on lithium supply chains. Though Na-ion technology still lags behind Li-ion in energy density, advancements in electrode materials and electrolyte design are steadily improving its performance. Future research should focus on enhancing energy density, efficiency, and durability to make these technologies viable for EV applications, contributing to a more sustainable and diversified ES ecosystem.

In recent years, there has been an increase in rechargeable batteries using nickel–cadmium (Ni-Cd), sodium nickel chloride (NaNiCl2), and sodium sulfide (Na2S) [140].

The concept of capacitors includes ES using energy-type batteries like supercapacitors (SCs) and ultracapacitors (UCs), which maintain energy through parallel plates isolated by a block. These devices offer a longer life than conventional alternatives since they do not encounter chemical variation. Moreover, UCs feature an energy density nearly 10% higher and a power density that can be 10 to 100 times greater than conventional battery units, allowing for greater storage capacity for both power and energy [141,142]. Nevertheless, ultracapacitors necessitate advanced digital regulation systems to manage fast current oscillations through charging and discharging phases [143]. They are most effective in power devices, functioning as pulse loaders or power buffers. Recent advancements in electrolytes and nanostructured electrodes may aid lower production costs while improving the electrical performance of UCs [144,145].

Flywheels serve as mechanical ES devices by capturing kinetic energy through the rapid spinning of a mass, distinguishing them from other storage methods like batteries and UCs. A flywheel energy system includes key parts such as a quick spinning rotor, a motor/generator, and devices for power conversion [146]. In wind power applications, the flywheel ES is crucial for RE storage [147]. The integration of batteries and ultracapacitors into hybrid energy systems can achieve optimal efficiency [148]. Other hybrid methods, such as simultaneously relating the ultracapacitor and battery or utilizing a DC–DC inverter, have also been explored in Ref. [149]. In these configurations, a reversible DC–DC inverter regulates electrical power flow between the source and the loads [150]. Additionally, connecting an FC with a battery can enhance power, energy, and overall system efficiency. Hybrid ES devices, which combine different types of battery storage, are frequently implemented to address power outages associated with renewable energy generation. Electricity storage can mitigate low-frequency power variations from renewable sources, while power storage can compensate for high-frequency outages.

10. Cost Analysis of Charging Infrastructure

As the adoption of electric vehicles (EVs) continues to accelerate, the development of efficient and scalable charging infrastructure has become a critical focus. Charging systems, whether integrated into vehicles or deployed externally as standalone facilities, play a pivotal role in supporting the growing EV ecosystem. On-board charging systems, integrated directly into EVs, offer a compact and user-friendly solution for personal and moderate power charging needs. Conversely, off-board charging systems, which operate as external charging stations, are designed to handle higher power demands and accommodate multiple vehicles simultaneously. Both systems present distinct advantages and challenges, shaped by differences in investment costs, operational expenses, and revenue potential. This analysis explores the evolving financial and operational characteristics of on-board and off-board charging systems, providing insights into their respective roles in the expanding EV market. Figure 5 presents the cost analysis of on-board and off-board charging systems (2019–2024).

The initial investment costs for on-board and off-board charging systems exhibit distinct trends over the years, driven by advancements in technology and market dynamics. On-board charging systems, which integrate chargers directly into vehicles, started at a relatively low cost of USD 5.2 million in 2019, declining to USD 4.0 million by 2024. This consistent decrease is attributed to improvements in manufacturing processes, the miniaturization of components, and economies of scale resulting from the growing adoption of EVs. In contrast, off-board charging systems, characterized by their larger infrastructure requirements such as charging stations and grid connections, began with significantly higher investment costs of USD 10.5 million in 2019, reducing to USD 8.0 million by 2024. This decline reflects increasing efficiency in deploying large-scale infrastructure as the EV market matures and demand stabilizes. Operating costs for both systems show an upward trend, largely driven by increased usage, maintenance requirements, and fluctuations in energy prices. On-board charging systems, designed for simpler operational scenarios, incur relatively lower operating costs, rising from USD 0.9 million in 2019 to USD 1.4 million in 2024. In comparison, off-board charging systems, which cater to public and commercial charging needs, experience higher operating costs, growing from USD 1.8 million in 2019 to USD 2.4 million in 2024. The larger infrastructure footprint and higher energy demands of off-board systems contribute to these elevated operational expenses. Revenue generation for both systems reflect the accelerated adoption of EVs, with a steady increase observed over the years. On-board charging systems generate revenue starting at 0.4 million USD in 2019, rising to 2.5 million USD by 2024, underscoring their growing integration in personal vehicles. Off-board systems, benefiting from their broader customer base and capacity for high-power charging, generate higher revenues, beginning at 0.8 million USD in 2019 and increasing to 3.0 million USD by 2024. This highlights the commercial viability of off-board systems in serving multiple users and meeting high-demand scenarios.

When combining investment and operating costs while considering revenue generation, on-board systems consistently demonstrate lower total costs compared to off-board systems. This aligns with their design, which is tailored to individual usage scenarios with lower power requirements. Although off-board systems incur higher overall costs, their ability to handle higher power demands and serve multiple vehicles makes them well-suited to public and commercial environments, where their increased costs are offset by significant revenue potential. The comparative analysis underscores the distinct applications of the two systems. On-board charging systems are cost-efficient and simpler to operate, making them ideal for personal EVs or situations where moderate charging power is sufficient. Meanwhile, off-board systems, designed for high-demand environments such as public charging stations and commercial fleets, justify their higher costs through broader operational scope and revenue generation capabilities, highlighting their suitability for supporting the growth of EV infrastructure. Figure 6 illustrates the cost comparison between the charging infrastructure and energy losses for on-board and off-board chargers, which provides a nuanced understanding of their advantages and disadvantages.

The infrastructure costs for on-board chargers, as calculated, show a steady decrease from USD 5.2 million in 2019 to USD 4.0 million in 2024. This decline reflects technological advancements, cost reductions in manufacturing, and increased adoption of EVs. Off-board chargers, while starting at a much higher cost of USD 10.5 million in 2019, also demonstrate a downward trend, reducing to USD 8.0 million by 2024, driven by economies of scale in deploying large-scale charging stations and improvements in grid connection efficiency. Despite these reductions, off-board chargers remain significantly more expensive to deploy due to their extensive infrastructure requirements. Energy losses also play a critical role in understanding the trade-offs. The results reveal that on-board chargers experience higher energy losses, starting at 8% of the energy supplied in 2019 and gradually improving to 6.5% by 2024. These losses are a consequence of the compact and less efficient AC–DC converters used in vehicles, which prioritize size and integration over optimal performance. For example, in 2019, an on-board system supplying 50 GWh of energy lost approximately 4 GWh, while in 2024, supplying 100 GWh, it lost about 6.5 GWh. Off-board chargers, in contrast, have lower initial energy losses, beginning at 5% in 2019 and improving to 4% by 2024. These lower losses are attributed to the use of larger, more advanced conversion systems in the external infrastructure. For instance, in 2024, an off-board system supplying 100 GWh of energy lost only 4 GWh, highlighting its superior efficiency in high-demand scenarios. The comparative analysis underscores the trade-offs between cost efficiency and energy performance. On-board chargers, with their lower infrastructure costs, are highly suitable for individual or low-power applications where affordability and independence are prioritized. However, their higher energy losses make them less effective in scenarios requiring sustained high-energy throughput. On the other hand, off-board chargers, despite their higher deployment costs, provide significant advantages in energy efficiency and scalability. Their ability to serve multiple vehicles with lower energy losses and faster charging speeds makes them ideal for public charging networks and commercial fleets, where infrastructure costs can be spread over a larger user base. Integrating the results further highlights the economic implications of these systems. Over the analysis period, the cumulative energy losses for on-board systems consistently exceed those of off-board systems, resulting in a higher overall energy cost when usage scales up. For stakeholders, this suggests that while on-board chargers remain cost-efficient for residential or low-power usage, off-board chargers are better suited for high-traffic, high-demand applications where their operational efficiency can offset their higher initial investment. This detailed integration of cost and energy loss data provides a comprehensive framework for evaluating and optimizing charging solutions in the evolving landscape of electric mobility. Figure 7 shows the energy loss comparison (2019–2024).

As illustrated in Figure 8, FCEVs, along with HEVs, PHEVs, and BEVs, exhibit distinct energy consumption and efficiency levels under identical driving conditions. HEVs consume the most energy (~470,000 Wh) with the lowest efficiency (~35%) due to combustion engine losses and limited regenerative braking, making them suitable for areas with minimal charging infrastructure, but they are inefficient for energy conservation. PHEVs have a better efficiency of ~45%, consuming ~380,000 Wh, as they rely more on battery power for urban driving while using fuel for extended ranges. BEVs are the most efficient (~85%) with the lowest energy consumption (~190,000 Wh) by eliminating combustion losses and maximizing regenerative braking, making them ideal for urban environments. FCEVs, consuming ~320,000 Wh with ~50% efficiency, outperform HEVs and PHEVs but remain less efficient than BEVs due to hydrogen-to-electric conversion losses. However, they offer faster refueling and a longer range, making them viable where hydrogen infrastructure exists. The results confirm BEVs as the most energy-efficient EVs, followed by FCEVs, PHEVs, and HEVs, emphasizing the advantages of electric propulsion in reducing energy usage and optimizing efficiency.

Figure 9 compares the charging performance of on-board, off-board, and FCEV systems, showcasing their distinct characteristics. On-board chargers, operating at lower power levels (1.9–22 kW), follow a gradual CC–CV charging profile, requiring extended charging times (~4.5 h) due to lower efficiency and higher energy losses, making them more suitable for overnight home charging. Off-board chargers, with significantly higher power capacities (50–350 kW), enable rapid charging (~30 min for 80% SOC), making them ideal for public fast-charging stations and reducing downtime. FCEVs, benefiting from hydrogen refueling, achieve even faster replenishment (~1 h), surpassing on-board chargers while maintaining flexibility for long-range travel. The comparison highlights the advantages of fast-charging solutions in reducing wait times, supporting EV adoption, and addressing range anxiety, with off-board systems and FCEVs emerging as the most efficient charging options for high-demand applications.

11. Future Developments in EV Charging and Sustainable Energy Integration

The future of the EV charging infrastructure will be shaped by advancements in UFC technologies, ES solutions, smart grid integration, and renewable energy deployment. Ultra-fast-charging stations exceeding 350 kW will significantly reduce charging times, while the introduction of megawatt charging systems will enable efficient charging for heavy-duty electric vehicles, including trucks and commercial fleets. In parallel, innovations in battery technology, such as solid-state batteries and lithium–sulfur batteries, will improve energy density, lifespan, and charging speed, reducing reliance on critical raw materials. For FCEVs, advancements in hydrogen storage, including high-pressure tanks, liquid hydrogen, and metal hydrides, will enhance the viability of hydrogen refueling stations. The integration of V2G and G2V technologies will transform EVs into ES assets, enabling bidirectional energy exchange to stabilize the power grid and optimize energy use. Additionally, decentralized solar and wind-powered charging networks will play a crucial role in reducing reliance on fossil fuels while enhancing the resilience of the EV infrastructure. In Tunisia, where renewable energy potential is high, future developments should focus on leveraging solar and wind power for EV charging, expanding public charging infrastructure, and exploring hydrogen refueling solutions to facilitate the adoption of FCEVs. The establishment of smart charging networks, government incentives, and public–private partnerships will be essential in overcoming infrastructure challenges and accelerating the transition to sustainable electric mobility. By addressing these developments, Tunisia can position itself as a regional leader in clean transportation, ensuring a scalable and environmentally friendly EV ecosystem, contributing to both national and global sustainability goals.

Future research will focus on enhancing smart grid interactions, developing hybrid BEV–FCEV charging hubs, and advancing next-generation battery and hydrogen storage solutions. Tunisia, in particular, should explore solar-powered charging, smart charging networks, and hydrogen refueling infrastructure to build a resilient and efficient mobility ecosystem. By addressing these challenges, a sustainable and scalable EV infrastructure can be achieved both globally and in Tunisia, ensuring the country’s role in the transition toward clean and energy efficient transportation.

As part of our future research, we aim to analyze and optimize the integration of bidirectional power flow in Tunisia’s EV charging infrastructure, focusing on V2G and G2V interactions. Additionally, we will investigate the feasibility of implementing ultra-fast-charging stations powered by renewable energy sources to enhance charging efficiency and grid stability. Another key aspect of our study will be the development of an intelligent energy management system for multi-source hybrid charging stations, incorporating battery storage and hydrogen FC to improve energy reliability and sustainability. Our research will provide valuable insights into the technical, economic, and regulatory challenges of EV infrastructure deployment in Tunisia, paving the way for a cleaner and more efficient transportation ecosystem.

12. Conclusions

This paper examined the EV charging infrastructure, covering both BEVs and FCEVs. Conductive charging plays a key role in BEV adoption, with standardized technologies ensuring efficient and safe charging. The evolution of charging standards in the USA and Europe highlights progress toward universal compatibility and accessibility. Beyond BEVs, this study emphasizes the importance of hydrogen refueling infrastructure for FCEVs, particularly for long-haul and commercial transportation. Despite challenges such as high infrastructure costs and hydrogen production efficiency, advancements in green hydrogen and hydrogen corridors are supporting FCEV adoption in Japan, Germany, South Korea, and California.

Renewable energy integration is crucial for reducing emissions and enhancing energy security. In Tunisia, the strong potential for solar and wind energy offers an opportunity to develop a sustainable EV charging network, but challenges remain, including limited public charging stations, regulatory gaps, and grid limitations. Additionally, Tunisia’s interest in green hydrogen production could enable future FCEV adoption in the commercial and industrial sectors.

Future research will focus on optimizing bidirectional power flow integration in Tunisia’s EV charging infrastructure through V2G and G2V interactions, enhancing grid stability and energy efficiency. The implementation of ultra-fast-charging stations powered by renewable energy sources will be explored to improve charging speed, grid resilience, and sustainability. Additionally, an intelligent energy management system will be developed for multi-source hybrid charging stations, incorporating battery storage, hydrogen FC, and supercapacitors to enhance energy reliability. Further investigation will address the role of multilevel inverters in bidirectional power flow management, ensuring efficient energy conversion and control within hybrid EV charging hubs. Moreover, advanced power control techniques using multivibrators will be examined to optimize system response time and minimize energy losses. By tackling these challenges, future research will contribute to a scalable, resilient, and sustainable EV ecosystem in Tunisia, fostering clean mobility and energy-efficient transportation solutions aligned with global decarbonization goals.