Grid Integration ofElectric VehiclesA manual for policy makers

Executive summary The electrification of road transport is a major driver of decarbonisation in the IEA’s Net Zero Emissions by 2050 Scenario, and providing charging solutions will be crucial for supporting this transition. The power sector plays a key role in ensuring a secure supply of electricity for electric vehicle (EV) charging, and in taking advantage of EV flexibility through seamless integration with the power system. This manual is intended to support policy makers in assessing and mitigating the impacts of electric mobility on the power sector and designing strategies to leverage the flexibility of EVs. It provides key recommendations in four main areas: the readiness of institutions, impact assessment of EV charging, design of operational measures to integrate EVs as an energy resource, and power system planning.

Assess the power system impacts Electric vehicles (EVs) interact with the power system whenever they are connected to a charging point. Like many other electrical loads, EV charging can cause operational challenges and require upgrades based on the power drawn from the system and the specific location from which the power is drawn. The impacts can be classified as those affecting the capacity limits of the different components of the network, those that affect the power quality for the end users and those that affect the larger power system.

Deploy measures for grid integration Grid integration is the process of adapting power system operations to accommodate the entry of new energy technologies in a cost-effective manner. For distributed energy resources such as EVs, the following characteristics help distribution companies determine the extent to which the resource could affect or fully participate in the system.

  • Visibility: location information of the connected resource. For EV charging, this could entail information on the charging status of electric vehicle supply equipment (EVSE) and load profiles.
  • Control: the ability to influence the operation of the connected resource. For EV charging, this could include the ability to send signals to start and stop charging or to modulate the power of a connected EV.
  • Guidance: the ability of the network operator to provide locational guidance on where the connection should preferably take place, taking into account the minimisation of upgrade costs or the improvement of system performance.

EV hosting capacity map of New Jersey, United States

Varying local connection fees based on the available grid capacity can also serve as a locational signal. By passing a portion of the costs on to the CPO, they can then make a feasibility assessment of the charging station plans given possible higher charging rates. Making the connection fees more reflective of the needs of the grid can help avoid crowding in congested locations.

Vehicle-grid integration ecosystem and communication protocols

It is important to have a common communication protocol between the EVSE and the power system that is facilitated by managed charging actors. Currently, efforts are being made towards the global harmonisation of communication protocols, including those between EVs and EVSE, to aid in interoperability when crossing international borders. Standardised communication protocols bring about systemwide benefits but can also carry risks. Using insecure protocols that lack authentication and encryption can create entry points for cyberattacks. While it is not in the scope of this manual, policy makers should conduct a cybersecurity assessment and plan for mitigation measures for charging operations.

EV charging has strong potential synergies with renewables At the bulk energy level, load shifting of EV charging to more favourable times of the day can increase consumption and reduce the curtailment of transmission-connected renewables, leading to a better business case. In Korea, for example, flexible EV charging of 30% of the expected EV fleet in 2035 could reduce operating costs by USD 21/MWh and peak costs by USD 18/MWh, corresponding to 21% and 30% of the costs, respectively. It could also lead to a 63% emissions reduction compared to a full internal combustion engine fleet. Matching the EV load to the availability of renewables could also provide a better business case for renewable energy developers by reducing curtailment.

There are also potential synergies at the distribution level. Currently, areas with significant penetration of rooftop solar PV can experience problems with high local voltage (overvoltage) due to the injected energy not being matched with consumption. These conditions often arise during sunny weekends when consumption is low and PV generation is high. On the other hand, simultaneous EV charging in the evening when consumption is high can cause the opposite effect of low voltage levels (undervoltage). Co-ordinating the operation of EV charging and solar PV could increase the mutual hosting capacity within a distribution grid by keeping delivery within the contractual voltage limits. For example, a modelling study in Sweden shows that the distribution grid could host a higher penetration 12 of EVs and distributed PVs when co-ordinated with a management system compared to when they are uncoordinated.

Framework for grid integration of electric vehicles

Conduct proactive grid planning The typical process where grid operators respond to connection requests, in this case from EVSEs, can delay the rapid uptake of EVs. In some cases, connection requests can take from 6 months to over a year. Policy makers can streamline the interconnection process to help accelerate this process. As the number of EVs increases, the grid will eventually need to be reinforced and expanded. Reinforcing the grid to accommodate new load can take years for permitting and construction and can thereby slow down the electrification process. Additional new charging points can utilise the existing network. In many cases, however, fast-charging stations may require a new grid connection and grid reinforcement where the existing network capacity is constrained. The connection process from request to construction approval can be a lengthy procedure. Hence, proactively planning the grid can help anticipate the connection requests.


This entry was posted in Grid Connected, Grid Interactive Distributed Solar Energy Systems, Grid Storage, Off-grid, Renewables, Solar, Solar Policy, Solar PV and tagged , , , , , , , , , , , , . Bookmark the permalink.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s