EV electricity demand
The deployment of electric vehicles to decarbonate the transport sector also raises the issue of changes in electricity demand. The growing number of EV in the vehicle fleet and the increasing battery sizes require well-developed charging infrastructure. However, while EV adoption is expected to moderate the overall increase of power demand until 2050, it will significantly affect the electricity load curve, increasing peak demands (Town et al. 2022).
EV charging needs are expected to increase peak loads, especially on a local grid distribution level. This effect will be exacerbated by the growing uptake of fast and ultra-fast chargers. Indeed, while charging time from slow charging infrastructure (i.e., more than 1 hour) can hinder the EV adoption rate, fast and ultra-fast chargers seem to provide a better alternative for consumers. The charging time is then reduced to less than 1 hour (i.e., can reach 20 min for ultra-fast charging) compared to, for instance, between 6 and 12 hours for level 2 chargers. However, the necessity of fast and ultra-fast chargers to ramp up with EV charging demand also increases the issue of high peak demands. It means that charging management is crucial to ensure EV use not to be hindered by grid capacity.
Smart charging and V2X, V2G
Managing the charging processes for EV is a solution to mitigate the challenges induced by EV uptake. It consists of controlling and coordinating the charging schedule. It is made possible by the fact that most cars are parked at any time. Such charging strategies could limit the peak demand increases up to 41% compared to up to 51% with uncontrolled EV charging (Mangipinto et all 2022). Two main options are developed (Saldana et al 2019):
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Smart charging, or unidirectional charging
In this case, the vehicle cannot provide back electricity to the grid. It consists of coordinating the vehicle charging time and rate with the current electricity demand/offer to support the distribution network. For example, scheduling charging time can allow excess of power from renewables to be used accordingly to charge the vehicle. Besides, charging rate can vary to balance and support the electricity load.
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Bidirectional charging, with V2G (Vehicle to Grid) or local V2H (Vehicle to Home), V2B (Vehicle to Building) or V2X (vehicle to everything)
Both systems allow the vehicle to send back electricity. It can provide extra support to the network distribution services, either locally or to the grid. For V2X, the vehicle is used both as a storage possibility or as a local and temporary power supply during high power demand or emergencies. For V2G, the vehicle can directly provide electricity to the grid. It can support power grid regulations. For example, it is useful to limit the period of peak loads. This application is called peak shaving.
References and useful links:
Town G, Taghizadeh S, Deilami S. (2022) Review of Fast Charging for Electrified Transport: Demand, Technology, Systems, and Planning. Energies, 15(4),1276. https://doi.org/10.3390/en15041276
Mangipinto, A., Lombardi, F., Sanvito, F. D., Pavičević, M., Quoilin, S., & Colombo, E. (2022). Impact of mass-scale deployment of electric vehicles and benefits of smart charging across all European countries. Applied Energy, 312, 118676. https://doi.org/10.1016/J.APENERGY.2022.118676
Saldaña, G.; San Martin, J.I.; Zamora, I.; Asensio, F.J.; Oñederra, O. (2019) Electric Vehicle into the Grid: Charging Methodologies Aimed at Providing Ancillary Services Considering Battery Degradation. Energies, 12, 2443. https://doi.org/10.3390/en12122443