This McKinsey study on expected impact of EVs on the grid states that EV's won't contribute significantly to the electricity demand in the coming decades, but highlights that electric vehicles have the potential to increase peak demand, putting strain on the grid and requiring more costly investment in upgrading grid infrastructure (in the worst case, equating to several hundred euros per EV). It then introduces a number of potential mitigations for this risk.
The summary of their analysis is shown here, followed by my interpretation.
To realize these benefits, energy players must make some up-front investments in smart-charging infrastructure and work to achieve effective collaboration with other stakeholders. But once these aims are established, EVs will no longer pose a cause for concern from an energy-system perspective. Instead, they will become a source of benefit by making the system more cost-effective, resilient, and green.
Time of use tariffs and other cost incentives to shift charging away from peak energy consumption times will have a significant impact on the affect EV adoption will have on the grid.
For some people, the savings of charging their car when the power is cheaper might not be enough to change habits or spend brain power thinking about. For these people, it might be more effective to simply plug their car in any time it is home and to have a coordinated grid-scale system manage when and how fast to charge.
Going one step further, aligning incentives by compensating individuals for participating in energy supply will not only reduce demand at peak times (since the batteries that may have been charging at that time are not), but result in energy supply being colocated with demand, actively supporting the transformers and distribution networks which may otherwise reach or exceed capacity.
We need much more work here in Australia, as there are many aspects of this which are currently impractical or not supported by suitable legislation or specifications.
Similarly to V2G, as the price of batteries drop, it may make sense to have storage located close to expected demand that can be utilised during the peak times. This helps to match the demand when supply from renewable sources is low and would be fulfilled by less desirable and more expensive means such as gas peaker plants. It also has the added benefit of increasing the daytime demand for energy, where it is predominantly coming from variable renewable sources. This avoids curtailment of renewable power, increases the certainty of demand for future variable renewable power infrastructure, leading to more investment and allowing the grid to reach higher renewables penetration.