Wide availability of public electric vehicle charging stations (EVCSs) would alleviate the range anxiety of potential consumers, thus accelerating electric vehicle (EV) growth. According to estimates, government investments in the installation of public EVCSs facilitates four times higher adoption of EVs than subsidising their demand. Hence, India plans to exponentially scale the number of EVCSs in the country from approximately 1,650 to 22,000-25,000 over the next three to five years.
EVCS technologies have several subcomponents, including grid type, charging level, battery swapping ability and type of charging method. The extent and efficiency of these technological developments will shape the trajectory of EV adoption in India.
Types of chargers
EV chargers can broadly be classified into wired/conductive chargers and non-conductive/wireless chargers. Wired chargers mostly use cables, while wireless chargers utilise inductive charging. Needless to say, wireless charging is at a nascent stage and is expected to take off in the coming decade, depending on viability.
Meanwhile, conductive charging has three variants – cable-based charging, battery swapping and pantograph-based charging. Battery swapping involves replacing exhausted batteries at an EVCS with charged ones. Pantograph chargers are useful for heavy duty, long distance vehicles such as e-trucks and e-buses, as they can supply a large amount of current for fast charging. Cable-based charging accounts for the majority of charging systems and is likely to continue growing rapidly, as EVCSs based on this technology have been proven to be commercially viable and technologically feasible.
Broadly speaking, EVCSs are classified on the basis of the charging current. AC chargers are a simple and affordable way of charging EVs. However, these chargers take six to eight hours to fully charge a vehicle, making them more suitable for deployment in households than in commercial settings. On the other hand, DC chargers are high capacity chargers that charge EVs more rapidly, given that they bypass the AC-DC conversion process.
Cable-based charging stations are further classified on the basis of their charging speed, with different standards in different countries. These include:
- Type-2 chargers, which are based on both AC and DC. These chargers operate on single-phase or three-phase input power systems, depending on the charger rating. They can provide a current of 3.3 kW to 43 kW, with around 400 V of electricity. They are ideally deployed in households, as they are affordable and very modular in design.
- GB/T chargers, which are DC chargers with a current output of 10-15 kW for low-power EVs and 27-250 kW of output for heavy duty vehicles. The government recommends installing these chargers. However, these chargers do not utilise control protocols based on power line communications, rendering it harder for an EVCS to incorporate internet of things in payment mechanisms, or automation.
- Charge de Move (CHAdeMO) chargers, which are DC chargers that can provide currents of up to 62.5 kW. However, newer EVs are switching to combined charging systems (CCSs) because of their modularity.
- CCSs utilise DC charging, allowing them to provide power of up to 350 kW and voltage of 200-1,000 V. These are used in charging stations and commercial areas, as well as to charge buses and heavy duty vehicles due to their rapid charging speed.
Battery swapping
An alternative battery recharging method that is receiving global attention is battery swapping, whereby a depleted EV battery is removed from the vehicle and replaced with a fully charged one. In the Indian market, the strong growth prospects of electric three-wheelers and two-wheelers are driving a rush to start battery swapping services. For instance, Terra Motors, a Japanese EV manufacturer focused on South Asian markets, has teamed up with Bengaluru-based Sun Mobility, a local battery developer, to build battery swapping stations. The two firms will also work together to build a network of battery swapping stations in India. Meanwhile, Sun Mobility is partnering with Amazon India in Maharashtra to install battery swapping stations at its warehouses.
Battery swapping allows drivers to replace depleted packs quickly with fully charged ones, rather than plugging the vehicle into a charger. Terra and Sun are hoping that this approach will appeal to taxi operators using EVs. The companies are considering charging users up to Rs 50 per swap. Further, a local unit of Honda Motors is set to roll out a battery sharing service in the country. Honda plans to install battery swapping facilities at Hindustan Petroleum Corporation Limited retail outlets.
In order to expand the country’s EV and battery market, the Government of India announced its plan to launch a Battery Swapping Policy during Budget 2022-23, followed by the release of a draft policy by NITI Aayog. To promote the battery-as-a-service (BaaS) business model, the government has allowed the sale and registration of EVs without batteries.
Role of smart chargers
Given that EVCSs and private EV chargers are expected to account for 3-8 per cent of India’s electricity consumption by 2030, depending on the growth of EVs, they are classified on the basis of the grid system used by the EVCS. EVCSs based on traditional grid systems that are unidirectional by nature procure electricity from the grid to charge EVs. Meanwhile, EVCSs based on bidirectional grids have specific captive capacities (such as rooftop solar) for charging EVs during peak hours, while exporting surplus electricity back to the grid. In off-peak hours, these EVCSs procure electricity from the grid.
Currently, most EVCSs operate on traditional grids. However, such uncoordinated charging with sudden peaks and troughs in demand can potentially cause fluctuations, leading to outages and deterioration of the grid. Hence, in the coming years, the growth of EVCSs in India will be accompanied by the growth of smart grids and captive sources of power. It makes more business sense for an EVCS to have captive capacity, as this reduces the operational overheads related to power procurement.
In a coordinated charging system with a reliable communication network, the whole operation is controlled directly by a third-party controller or aggregator. The aggregators and controllers are responsible for achieving objectives such as cost minimisation, power loss minimisation and others. In this case, EV users, and private and public charging station operators, are involved in charging management by selling or buying electric power.
Smart charging entails the use of smart energy management software, which determines the best time to charge and the best energy source to use for charging vehicles. Such software uses advanced algorithms and demand-side response to provide near-real-time load balancing that dynamically distributes energy to and from the grid, helping prevent the demand from exceeding the grid capacity during peak usage times. In essence, smart energy management adds another dimension to EV smart charging. It optimises energy consumption based on grid constraints, energy pricing, renewable energy availability, locally stored energy, preconfigured EV owner preferences and driver needs. Smart energy management optimises charging infrastructure by efficiently delivering the available power to EVs, and shifting charging loads across energy sources to safely deliver electricity without interfering with the power needs of buildings, homes or other power consumers.
Another radical smart charging technology is vehicle-to-grid technology, which proposes pushing electricity from an EV battery to the grid during off-peak hours. This can also create an extra power source when weather-dependent renewable energy sources are not available. For example, a home that uses solar power cannot generate electricity at night, but an EV could provide a secondary source of power if needed. This technology could potentially elevate the business proposition and commercial viability of EVs and EVCSs.
Issues and challenges
High EV integration into the distribution grid will create challenges and concerns such as increased peak demand, harmonic distortions and frequency; and unpredictable, dynamic behaviour. Moreover, EVs require a considerable amount of electric energy from the power grid, which is mostly delivered by the grid from fossil fuel-based power plants. Thus, EVs may contribute to carbon emissions, depending on the source of energy used to charge the battery. There may be substantial problems springing from differing charging standards. Hence, it is increasingly essential that charging stations, chargers and other equipment, batteries, AC-DC power converters, etc., adopt uniform standards. Delays in land acquisition and reception of regulatory permits may in turn delay the deployment and installation of EVCSs, thus lowering the adoption of EVs.
EVs utilise IoT to relay sensitive data such as charging levels and travel routes to aggregators and EVCS companies, so that they may reserve parking slots in advance. However, such communications require confidentiality. It remains to be seen whether the privacy of individuals will be respected.
The way forward
The growth of EVs is directly tied to increasing the number of EVCSs, as demonstrated by several studies. It is thus important to account for the type of charger used, the nature of an EVCS’s connection with the grid (bidirectional or unidirectional). These factors will determine the success of EVCS and, by extension, the future trajectory of EVs.