A paper published last month by the European Distribution System Operators' Association for Smart Grids (EDSO) discusses how distribution system operators (DSOs) can sidestep the challenges of integrating electric vehicles into their network.
The world population is transitioning to electric vehicles (EVs) at an increasingly fast pace. For instance, a prediction by Bloomberg New Energy Finance estimates that EVs will make up a third of the global fleet by 2040. And, with electric vehicles (EVs) capable of soon becoming cost competitive in comparison to traditional fuel vehicles, DSOs have a problem to consider: how to effectively integrate them into distribution grids.
In the paper, EDSO calculates that the additional demand can be twice as high as current peak power demands. This means that one of the main challenges faced by utilities is how to manage the peak capacity demand that can happen once a large number of EVs is plugged in at the same time.
Local grid congestions and voltage constraints can happen as a result, potentially limiting power availability and not answering to demand. As such, smart charging - and all forms of flexibility - emerge not only as a solution, but as a necessity for DSOs to manage the grid appropriately. In fact, according to EDSO, flexibility on the EV demand is a requirement for e-mobility to fully take off.
How to enable smart charging
The paper, which is based on a survey carried out with 17 DSOs from 14 European countries, lists several necessary elements for DSOs to make smart charging available and functional. These include infrastructural adjustments, interoperability of ICT and data, smart capacity network tariffs, variable contracts, among others.
Changes at the infrastructure level involve technical and communication devices to manage the charging process, particularly at the low voltage level. Smart charging essentially consists of controlling time and rate at which the car is charged according to signals from the grid operator, enabling the car to stop charging at peak times. As such, for EDSO, it is crucial that DSOs have a communication and control system in place to manage the charging process. This enables the DSO to handle charging according to the grid constraints and customers’ needs.
Another viable option is enabling vehicle-to-grid (V2G) charging. This technology can be an essential tool for smart EV charging, turning the car into a temporary storage system to supply power to the grid at peak demand and charging the vehicle when overall demand is reduced. Projects utilising V2G technology are getting substantial financial incentives to take off, making V2G a point of interest for utilities.
This element ties into the need for interoperable ICT and data standards. According to the association, interoperability is critical for smart charging to be reliable and practical. Interoperable interfaces should coordinate data between the grid, the charging point and the EV. In fact, interoperability between systems and networks is an essential feature for utilities, allowing them to better adapt to the changing patterns of energy generation and consumption.
Offering financial incentives for customers is another possible move for the utilities: DSOs can offer smart variable contracts and set lower tariffs for charging EVs outside of peak hours. By doing so, the companies would relieve the electricity demand at those times, and customers would trade time flexibility for cost savings. EDSO suggests that engaging with customers and empowering them to participate in the smart charging process is beneficial for both parties.
Integrating distributed energy resources
Another significant element that can contribute towards more efficient smart charging is the integration of distributed energy resources (DER). Smart charging can be a medium-term solution to optimise local DER integration - it can adjust the charging profiles to the supply from renewable energy generation.
Incentivising local DER optimisation can help DSOs with grid congestion issues, and brings the option to reverse the energy flow and enable V2G and vehicle-to-home charging.
Several pilot projects involving DERs and smart charging are already in place to test the feasibility of the combination of such technologies, such as the Smart Energy Network project in Germany and Switzerland. The system consists of a battery storage system in homes to stock power produced from solar photovoltaic systems. The stored power can be used to power the home and the customer's EV, and a smart feature predicts the energy needs of the home and EVs and sends power automatically where it is required.
However, even as DERs can be a means to mitigate the pressure put on the grid on peak demand times, it can also signify a potential loss of revenue for utilities when customers defect from the grid. That highlights the importance of DSOs to supply reliable and widely available smart charging infrastructure: providing flexibility can become a differential for companies to attract new customers and diversify their revenue streams.