Grid Integration of EVs: ENTSOE stresses on smart charging and V2G

The adoption of electric vehicles (EVs) in Europe has been increasing rapidly over the last few years and crossed 1.5 million cars in 2020 [including both battery electric vehicles (BEVs) and plug-in hybrids (PHEVs)]. In addition, the European EV fleet includes over 1,00,000 duty vehicles and 4,500 buses. EVs accounted for over 8 per cent of new registrations in the region in 2020. The top five countries–Germany, France, Sweden, Netherlands and Italy–accounted for the highest number of electric cars sold. In terms of EV sales percentage, Norway stood first at over 30 per cent. While EV penetration in central European countries is still low, northern countries have recorded the highest penetration.

European policymakers have clearly set the path towards the massive adoption of EVs. Future prospects are promising with a possibility of Europe’s combined EV market share touching 50 per cent by 2030 as per the International Energy Agency’s (IEA) Global EV Outlook 2020.

To support the rise of EV sales, the number of charging points is also increasing in Europe. Public charging points more than doubled in the last four years to reach over 2,00,000 units in 2020. Around 90 per cent of these are normal chargers (≤ 22 kW) and the remaining 10 per cent are fast chargers, equipped with a charging power of 50 kW or more. The Netherlands, France and Germany lead the region in charging infrastructure diffusion.

The EV charging process represents the concrete interface between the transport and electricity sectors and is the crucial component for ensuring the successful development of both. The adoption of a smart charging (which refers to charging that is supervised by an external control system) process currently represents the major gap to be covered in the complex ecosystem. This has been highlighted by the European Network of Transmission System Operators for Electricity (ENTSO-E) in its position paper on Electric Vehicle Integration into Power Grids released in March 2021. After an extensive analysis and the pooling of transmission system operators’ (TSOs) experiences, ENTSO-E considers electromobility to be a powerful means to decarbonise the transport sector as well as to provide flexibility services to the energy system. It calls for cooperation among all involved to promote the implementation and deployment of smart charging and vehicle-to-grid (V2G) technology to ensure an optimal vehicle-grid interaction. (V2G technology refers to smart charging with bidirectional energy flow capability.)

Given that the e-mobility environment is extremely dynamic and EV deployment could receive a sudden boost through the Green Deal and Recovery Plan, the paper calls for actions on its key findings without delay to transform a challenge into a valuable resource for optimal system management. ENTSO-E intends to contribute to the debate on technical and connectivity solutions, as well as on EV charging solutions and regulations to be adopted through the constructive cooperation with transport, urban planning, vehicle industry stakeholders and decision makers. It stresses that action needs to be taken immediately before mass EV deployment to avoid the need for future retrofitting of non-smart chargers.

TSOs need to operate beyond the boundaries of their traditional activities to ensure system operations are ready for future challenges. This is also highlighted in ENTSO-E Research, Development and Innovation Roadmap 2020–2030. The electrification of transportation requires TSOs to adapt and support the wider energy system integration, defined as ‘one-system of integrated systems’ centred around improved cross-sectoral integration. Smart charging and V2G solutions will create new markets and require new ways of modelling future generation and load profiles. Coordination between TSOs, DSOs, market participants and customers must go beyond the pure integration of markets and operations and expand into proactive planning. Enhanced TSO-DSO interactions for improved power flows and system security, in addition to suitable market platforms, will enable EVs connected at the distribution level to participate in energy and ancillary services markets.

Charging Infrastructure and use cases

Different technologies are available for EV charging. They can be broadly categorised as wired and non-wired solutions and battery swap. Wired solutions using conductive systems are the most prevalent as they guarantee the required power level, safety and interoperability with most vehicles. Conductive solutions using other contact types such as plates are currently in the prototyping phase. Non-wired solutions, which exploit inductivity principles, are being studied for highway applications. Battery swap is suitable for fleets, sharing and heavy-duty application besides special applications where speed is paramount. In the initial years of e-mobility development, the trend was to improve AC charging power (which relies on vehicles’ on-board chargers) up to 43 kW in some models. The present approach is to limit AC charging to less than 22 kW, while fast charging will be performed by a DC charger (which uses off-board power electronics installed at the charging station). The latter is becoming standard equipment for all EVs.

EVs are typically charged at different locations and with different power levels. From the user’s perspective, the optimal charging strategy would take full advantage of the car parking periods. Slow charging at homes and offices is a suitable solution for private passenger cars. When users cannot charge at home or at the office, public charging stations, slow and fast, fulfil their charging needs. For company fleets and buses with predictable usage patterns, there is often the possibility to charge at the company premises or in a deposit. Future mobility trends, such as inter-modality, mobility-as-a-service and autonomous drive, could change the volume of EVs and the location of charging points with a potential impact on the power grid.

Framework analysis takeaways

The shift to e-mobility road transport is likely to accelerate in the EU, both due to European and national legislation. For heavy duty vehicles (HDVs), green fuels and fuel cells may be more competitive. New mobility behaviours should be less impactful as a power grid stressing component. TSOs are currently focused on facilitating the electrification of road transport. EVs have to be considered as part of a wide and intertwined ecosystem that involves both transport and electric systems, as well as urban planners, tariff and market regulatory authorities and new charging operators. While electricity actors are not at the centre, even within the electricity segment of the ecosystem, TSOs are not at the core, unless they create a joint standpoint with DSOs as grid operators.

The deployment of other emerging technologies as well as future trends in mobility, such as hydrogen-fuelled EVs and shared mobility, should be closely monitored as they could also play a relevant role in addressing transportation needs and offering flexibility to the power system. It is crucial to understand and satisfy the charging process expectations of EV owners, which are the key actors of electric mobility deployment. EV powertrains and vehicles are intrinsically efficient and are progressively becoming mature. However, important improvements are still expected in the charging infrastructure and charging process, including digital services, data management, business models and value proposition. Grid operators should support the custom grid-friendly combinations of the several charging use-cases that will be deployed.

According to the analysed charging use cases, an uncontrolled charging process can lead to substantial challenges for the power system such as peak power demand. In contrast, managing the charging process by time scheduling and power profile management, or through market-based mechanisms (like flexibility markets), opens up new opportunities while limiting potential challenges.

Key opportunities provided by EV charging management

Several opportunities exist to profitably exploit EV charging. Smart EV charging can support large-scale integration of renewable energy generation by flattening the power demand curve, supporting generation fleet adequacy, and reducing system costs and CO2 emissions. EVs will also enable improved system management, both in terms of ancillary services and grid congestion. EV users will also benefit from lower charging energy costs, more reliable services and by contributing to more sustainable transport.

Reshaping the power load curve and avoiding overloads on distribution grids: The EV charging process can be shifted from peak to off-peak hours to avoid the need for additional power capacity during the peaks. The positive effect can be significantly increased if EVs charge during the day and provide energy back to the grid during the peak through V2G technology. To shift charging from the evening to the night, both time-of-use (ToU) tariffs and charging management by aggregators could be adopted.

Ancillary services for transmission grid operation: EVs can provide grid balancing services to help keep the frequency close to the reference of 50 Hz. EVs could modulate their charging profile and participate in reserve markets. EVs can also provide fast-frequency reserve, which is becoming progressively more relevant for transmission grid operation. With V2G chargers, voltage control for the transmission grid could also be performed. New rules should be applied to flexibility markets to include promising technology such as EVs to participate in the ancillary services markets. 

Management of grid congestions: EVs can be used as a distributed resource to reduce the risk of transmission grid congestion so as to minimise sub-optimal re-despatching (use of sub-optimal generation or loads). EVs could modulate their charging / discharging power according to the requests of the TSO, channelled through a market service provider. This could occur either in advance (day-ahead market) or during operation (intra-day and balancing market).

Voltage control in distribution grids: Bi-directional DC chargers can be used to perform voltage control on distribution grids, which is especially required when high shares of volatile RES are connected. It can occur through a direct control of bi-directional chargers performed by charging point operators or balancing service providers (BSPs).

Reduction of ‘over-generation’ by RES: EVs can schedule their charging process to fully match renewable generation availability, thus addressing the issues of over-generation and curtailment of green energy expected with higher levels of RES penetration. EV charging can be matched with PV production through new tariff schemes (hourly / quarterly or potentially real time-based tariffs) and by facilitating the possibility of charging at office premises or in park-and-ride facilities.

Behind the meter services: EVs can be used as other domestic storage systems. They can increase self-consumption in the presence of RES generation. Otherwise, EV batteries can be used to perform tariff optimisation, charging during low-price periods and then providing their energy for domestic loads during high-price ones. Tariff schemes and especially ToU and dynamic tariffs are the key enablers for these services.

Taking advantage of hyper chargers for HDVs: The daytime use of hyper chargers (150 – 350 kW and more) connected to high voltage (HV) grids and properly located will both avoid the risk of overloads at lower voltage levels of the grid during peak hours and enable the significant use of renewable energy. Hyper chargers designed for HDVs should be connected to HV grids and located close to existing lines.

Some of these opportunities provided by EV charging can be stacked and several benefits can be obtained with the same smart charging solution.

Key recommendations and TSO positioning

To optimally reap the benefits of multiple opportunities identified in the paper through the implementation of smart-charging and V2G solutions, ENTSO-E recommends the following:

• Promote coordinated planning for charging infrastructure and electric grid through scenario definition, improved modelling and considering the diffusion of hyper charger hubs on highways.
• Manage the charging process by promoting and facilitating a smart and V2G charging approach, thus smoothing peaks in the load curve.
• Deploy electromobility enablers including private and public charging infrastructure equipped with metering and communication capabilities and the adoption of common standards to guarantee the interoperability of charging networks and data, as well as effective data management.
• Enable a new consumer-oriented ecosystem by further enhancing TSO–DSO (distribution system operator) cooperation and defining roles and responsibilities to allow electricity grid operators to play an enabling role in fostering competition and unlocking the potential of flexibility from EVs.
• Update market rules and regulatory frameworks to implement grid tariff / power prices schemes, stimulating the further adoption of smart charging, and enable a higher number of services offered by EVs and their participation in flexible markets.

The key aspects supporting these required actions are: minimum technical requirements and standardisation, and dynamic pricing definition and updated market rules, as well as enhanced cooperation among the many different stakeholders from traditionally separated sectors: vehicle, battery and electronic industries, ICT and mobility service providers, transport and urban planning authorities, electricity market aggregators and operators, consumers and prosumers, and power grid operators.

In this multiple and complex system integration effort, TSOs can play an important role as grid operators, system operators and market facilitators (under the overarching concept of smart sector integration or ‘one system view’) to support optimal vehicle-grid integration. TSOs should devise a multisided action plan including undertaking dedicated pilots, studying potential opportunities of EV services in grid operations, enhanced cooperation with DSOs, promoting market-based demand for flexibility services, motivating EV users to adopt smart charging schemes and monitoring the evolution of the EV sector. TSOs must undertake demonstration projects to identify technical issues, as well as studies to assess the cumulative effects of EV smart charging solutions. Several TSOs are also pursuing related pilots (refer to table).

The way forward

The rapidly growing number of EVs that will interact with the power grid over the next few years will certainly require greater attention from grid operators. From the TSO perspective, EVs will both represent an additional load and a distributed flexible resource for grid services. It will be possible to address the potential system challenges and take advantage of all the potential opportunities only through an optimal management of the charging process.

By the end of this decade, a combination of private charging, slow public charging and fast public charging will be prevalent, with private charging covering the highest percentage of charging needs in the long run as well. In Europe, EV contribution with respect to total final electricity consumption is expected to increase from 0.2 per cent in 2019 to 4– 6 per cent in 2030. Despite being a significant growth, percentage values in total electricity consumption still remain low and will not imply substantial challenges in the future for the power system in terms of energy consumption. That said, in case smart charging is not properly deployed, massive EV diffusion could lead to power issues.

It is evident that coordinated planning and revised regulations are necessary to foster smart charging and V2G technologies. In this regard, TSOs have an important role to play, both directly as grid operators and as facilitators, and should take appropriate steps to study and balance the grid impact of such rapid EV uptake. The ENTSO-E position paper charts out the action plan for managing this growth beneficially for all the stakeholders from the grid perspective.

Project name	Involved TSOs	Main activities
EQUIGY	Terna, TenneT, SwissGrid, APG	Creation of a crowd-balancing platform as a link between existing ancillary services markets and the aggregators of distributed flexibility.
INCIT-EV Project	ELES (Slovenia)	Simulate cross-impacts between the electricity and transport sectors in terms of grids and electric markets.
E8 concept	ELES (Slovenia)	Address human behaviour, logistics and technical issues related to private vehicle and private location (smart) charging.
Professional vehicles charging pilot project	ELES (Slovenia)	Realisation of a charging area for professional vehicles close to the Ljubljana highway.
CECOVEL	REE (Spain)	A tool for monitoring and forecasting the electrical demand associated with the charging system of EV in real time.
Frequency responsive smart charging	REE (Spain)	Analysis of different kinds of regulation (power-frequency-subfrequency) both for EV charging and discharging (V2G).
FCR pilot project	TenneT (NL and Germany)	Providing primary reserve capacity using new technologies, cooperating with four parties.
aFFR pilot project	TenneT (NL and Germany)	Control of a fleet of vehicles with start / stop charging signals, in response to TenneT requests.
Bi-directional load management (BDL)	TenneT (NL and Germany)	Test of intelligent V2X charging management to reduce load peaks and for network stabilisation.
Study impact of EVs on Poland’s power system	PSE (Poland)	Forecasts for the development of the EV market and the expected impact of EVs on Poland’s power system balancing.
Sustainable mobility hub	Terna (Italy)	Vehicle-to-grid (V2G) pilot project.
Towards electric mobility in France	RTE (France)	Study on integrating up to 16 million EVs: adequacy under stress events, different chargers and batteries, economics of smart charging and V2G, carbon footprint.
mFFR pilot project	Statnett (Norway)	Enabling EVs and other new technologies in the mFRR market by lowering the minimum bid size to 1 MW and using electronic bid ordering.
Fast frequency reserves	Statnett (Norway)	Testing and development of a market for fast frequency reserves. Providers in 2018 included a portfolio of EVs.
Grid support from multiple assets	Statnett (Norway)	Improve estimation methods and estimates of flexibility in assets, particularly commercial buildings and EVs at long-term parking. Project owner NMBU, Norwegian University of Life Sciences.
Using EVs to balance the network	Elia (Belgium)	Within this use case, the partners assessed the possibility of combining uni-directional and bi-directional charging points for the delivery of FCR services in the Belgian power system.
Flexity – Enabling end-consumer to contribute in the energy transition	Elia (Belgium)	Within the IO.Energy use case ‘Flexity’, several companies wanted to investigate the drivers for consumers to participate in flexibility services and their possible interest in letting third parties operate their flexible assets. Over the course of a 10-month development and testing phase, the focus was on investigating the technical capability and economic potential for consumers and service providers to operate flexible household assets such as EVs.
Facilitating all-inclusive leasing contracts for EVs	Elia (Belgium)	Fully enabling energy-as-a-service for EV drivers would mean that any commercial third party could become the electricity provider for an EV, regardless of the charging location and the consumers’ current electricity contract. With this project, the partners are aiming to demonstrate how new market rules would facilitate the development of all-inclusive mobility contracts, such as leasing contracts that include the provision of electricity to charge the EV.
Charging EVs directly with green power generated by an energy community	Elia (Belgium)	In this project the partners want to develop an energy community featuring buildings equipped with charging points. The charging behaviour of the energy community participants will be optimised to allow them to maximise their use of local electricity generation, and to benefit from lower electricity market prices
Blockchain-based digital identities to integrate EVs into the power system	50Hertz (Germany)	A digital identity (DiD) is a unique representation of a device – like a passport. It forms the basis for a secure, trusted and efficient interaction between two parties. In the future, an EV driver might have access to multiple services from multiple providers. This creates the need to rethink and reinvent the interaction to develop a scalable, automated, end-to-end solution to enable flexibility from EVs. Partners therefore want to demonstrate that representing devices in the form of DiD facilitates the integration of EVs in the power market.
Digital measuring systems to capture the flexibility of EVs	50Hertz (Germany)	To use EVs and other flexible consumers with the goal of stabilising the electrical system, digital measuring systems in connection with so-called Smart Meter Gateways (SMGW) and control equipment will be indispensable technology in the future. This project is investigating and testing what kind of data exchange is necessary for this and how balancing power can be provided by a network of electric cars.
aFRR provisioning from BEV	TransnetBW (Germany)	Piloting of an existing smart charging solution for aFRR in the TransnetBW control area.
Smart charging project /DSM platform 2.0	TransnetBW (Germany)	Demonstration of smart charging and development of a platform to identify and visualise flexibility potential for the grid.
ELLA-futurae	TransnetBW (Germany)	Development and operation of a decentralised data and information router in a Europe-wide virtual balancing area to enhance the imbalance settlement process, market-based services and support grid operations.

The article has been sourced from Global Transmission Report