The electrification of transport represents a major systemic transformation of modern energy networks, as it introduces a new layer of distributed energy infrastructure in the form of batteries embedded in electric vehicles. Unlike conventional transport systems, where energy is consumed solely as fuel, electric vehicles are electrochemical devices capable of consuming, storing, and potentially returning electricity. This latter capability, enabled by bidirectional charging technologies such as Vehicle-to-Grid (V2G), turns vehicles into distributed storage units that can interact directly with the power grid. In the context of the energy transition, marked by the rapid growth of variable renewable energy (VRE), particularly solar photovoltaics and wind power, this evolution is especially significant because it introduces a new form of flexibility capable of compensating for the intermittency of electricity generation.
In power systems with high penetration of VRE, the central issue is no longer just electricity production, but its temporal alignment with demand. Variable renewables generate electricity in a non-dispatchable manner, creating frequent imbalances between supply and consumption. Storage thus becomes a critical infrastructure for absorbing excess generation and releasing energy during deficit periods. However, the economic value of storage does not depend solely on its initial cost or energy capacity, but primarily on how it is used within the system. Each charge and discharge cycle causes gradual battery degradation, meaning that their value is directly linked to usage intensity and their contribution to reducing overall system costs. The more batteries are used to smooth grid fluctuations, the more systemic value they generate—even if this increases their physical wear.
The electrification of transport profoundly alters this dynamic by multiplying the amount of storage resources available at the system level. Electric vehicles effectively act as mobile batteries with large capacities, typically between 40 and 100 kWh, which can be connected to the grid when parked. Through V2G, these batteries can not only be charged but also feed electricity back into the grid, actively contributing to system balancing. This transformation makes electric vehicles full-fledged energy actors, integrated into grid flexibility management. However, this intensive use of distributed storage increases the number of charge-discharge cycles, accelerating battery aging and raising significant economic questions regarding how degradation costs should be shared between users and the electricity system.
In France, the power system has historically been structured around highly dispatchable nuclear generation, progressively complemented by renewable sources. This configuration provides strong structural stability and limits production fluctuations. As a result, the need for large-scale storage is relatively low, since the balance between supply and demand can largely be ensured through the flexibility of dispatchable plants. Electric vehicles and their batteries therefore mainly play a marginal optimization role: they help smooth demand peaks, absorb occasional renewable surpluses, and improve overall grid efficiency. Battery cycling remains relatively limited, and the economic value of storage is primarily linked to specific flexibility services rather than a fundamental structural function.
By contrast, the Australian power system—particularly in regions such as South Australia—is characterized by very high penetration of variable renewable energy, especially residential solar photovoltaics and wind. This strong reliance on intermittent sources leads to significant variability in electricity generation, with periods of overproduction during the day and frequent deficits in the evening. In this context, storage becomes a central component of system operation, as it directly determines the ability to integrate large amounts of renewable energy. Batteries are therefore heavily used and undergo frequent cycling. Electric vehicles, through V2G, become a critical resource for stabilizing the grid by absorbing solar excess and redistributing it during peak demand. Unlike the French case, storage here is not a secondary optimization tool but a structural necessity for system operation.
This structural difference between the two systems leads to profoundly distinct economic and technical dynamics. In the Australian case, the marginal value of a battery cycle is very high, as each unit of stored energy helps avoid costly imbalances in a system heavily dependent on intermittent renewables. Distributed storage is therefore highly valued despite accelerated battery wear. In France, by contrast, the marginal value of storage is lower, as system imbalances are less frequent and can be managed through dispatchable resources. Battery cycling remains limited, and their role in the electricity system is less central. This implies that the profitability of V2G and electric vehicles as distributed storage depends strongly on the structure of the national energy mix.
Analyzing these two configurations highlights a fundamental relationship between transport electrification, renewable energy penetration, and storage value. The more a power system is dominated by variable renewable sources, the greater its need for flexibility—and the more essential batteries become to its operation. Transport electrification thus acts as a multiplier of distributed storage capacity, enhancing system resilience while increasing the complexity of grid management. However, this transformation relies on a delicate economic balance between the systemic benefits of flexibility and the individual costs associated with battery degradation. The key issue then becomes how these costs are allocated and what incentive mechanisms can align the interests of electric vehicle users with those of the electricity system as a whole.
In conclusion, integrating electric vehicles as distributed storage units fundamentally reshapes the value and role of storage in modern power systems, but the extent of this effect depends heavily on system structure. In a dispatchable system like France, storage remains a complementary optimization tool, whereas in a highly renewable system like Australia, it becomes a structural necessity for grid stability. Transport electrification thus acts as a differentiated catalyst for the energy transition, with economic and technical impacts that vary significantly depending on the level of variable renewable penetration and the inherent flexibility of the electricity system.