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Vehicle-to-Grid Charging Could Provide Grid Savings, Report Finds

Vehicle-to-grid (V2G) charging could provide substantial system savings for New England as it transitions to a clean energy future, according to a new report.

The report, Can vehicle-to-grid facilitate the transition to low carbon energy systems?, published in the journal Energy Advances, examined V2G potential in the context of the greenfield buildout and operation of renewable energy resources in the New England power system in 2050 in which there is high electric vehicle penetration and tight emissions constraints.

In that scenario, V2G in aggregate could shift load via demand response and shift excess renewables generation to periods of low availability and high net loads across a range of carbon constraints and participation rates, the report found.

If V2G electric vehicles were to participate in both power and ancillary markets, they could provide substantial value, primarily by displacing stationary storage.

With relatively little participation of just 13.9 percent of the New England light duty vehicle fleet, “14.7 gigawatts (GW) of 6-hour stationary storage is completely displaced and amounts to over $700 million in savings,” the report’s authors said.

Additional savings could come in the form of reductions in firm generation capacity and more efficient utilization of renewable resources, that is, reduced curtailments, they said.

“Not only does this analysis demonstrate V2G’s utility, but also the importance of how one chooses to measure its value (i.e., counting investment deferral), particularly in the context of future systems,” the report said.

The magnitude and nature of V2G savings also changes as the electric system changes. Under more aggressive emissions caps, for instance, V2G decreases the need to compensate for the intermittency of renewable resources by increasing the size of the deployed resources or by using fossil fuel generation with expensive carbon capture technologies, thus increasing the marginal value of V2G, the report found.

In addition, the nature of optimal V2G dispatch changes with participation rates. At low electric vehicle participation rates, V2G power injection is called on at a higher rate in order to shave uncontrolled evening charging loads, while higher participation rates rely on less injection through charge load shifting, the report said.

Similarly, the value of V2G could change depending on geography and the energy storage marketplace. Shorter duration storage, such as the 6-hour lithium ion batteries studied in the report, are not sufficient to remedy extended periods of low renewable generation availability, so firm generation is required to satisfy electric vehicle loads.

However, long duration storage and V2G could add flexibility to each other’s ancillary service offerings, with EV batteries providing rapid frequency regulation and long duration storage increasing operating reserve contributions. Pumped hydroelectric storage in the Northwest, for example, could provide “significant utility” throughout the region, the report found. The implications and interactions of more prevalent long duration storage with V2G are areas that “stand to be investigated further in future works,” the report’s authors said.