Enhancing energy efficiency with bidirectional EV Charging
Transforming EVs into Energy Assets
Bidirectional charging technology, as detailed in the RAP report, enables EV batteries to not only receive energy but also supply it back to the grid or buildings (vehicle-to-grid, or V2G). This multifaceted functionality of EVs can substantially contribute to resource efficiency and reduce the need for additional energy system investments. By integrating EVs into the energy system, significant potential is unlocked for renewable energy usage, especially in managing supply and demand imbalances.
The report identifies different use cases of bidirectional EV charging, ranging from powering individual appliances in off-grid scenarios to providing electricity system services and supporting grid stability. This versatility can lead to cost reductions for energy system users and vehicle operators alike, mainly through smart charging savings.
Overcoming Barriers and Setting Principles
The RAP report acknowledges several barriers to the widespread adoption of bidirectional charging, including technical, market, and regulatory challenges. To address these, the report proposes three key principles:
- Building Trust and Establishing Common Standards: Trust is critical for EV users to allow their vehicle batteries to be used for energy services. This involves ensuring that vehicles are ready for use when needed and that participation in energy services doesn’t lead to accelerated battery degradation. The report emphasises the need for widespread implementation of communication standards like EN ISO 15118-20 for compatibility between different manufacturers’ vehicles and charging points.
- Getting Prices Right to Guide Charging and Discharging: Effective price signals reflecting the real-time value or cost of energy can guide the optimal use of EV batteries for charging and discharging. The report suggests that prices from wholesale energy markets should be complemented by time- and location-varying prices for grid use. This approach could help align the charging and discharging of EVs with grid needs, thus enhancing grid stability and efficiency.
- Ensuring Equal Access and Treatment: The principle of equal access and treatment is vital for maximising the value of bidirectional charging. The report calls for policies ensuring that distributed energy resources like EVs have similar access to power markets as traditional generation resources. This includes rethinking measurement requirements and ensuring that smaller-scale, distributed resources are accommodated in market mechanisms.
Maximising Societal Benefits
The RAP report concludes that the integration of bidirectional charging and V2G services into the energy system can lead to broad societal benefits. These include lower electricity grid costs, better integration of renewable energy, and financial benefits for consumers. The proposed principles aim to remove barriers and enable EV batteries to play a significant role in the European power system, thereby maximising the systemic benefits of smart charging.
Source: Enabling two-way communication: Principles for bidirectional charging of electric vehicles | RAP