Vehicle-grid integration (VGI) refers to a range of methods for controlling the impact of electric vehicles (EVs) on the electrical grid. These methods can involve encouraging charging at specific times of day or at specific locations to relieve grid congestion, or reducing charging power levels during times of high demand. As an example, time-of-use (TOU) rates allow EV drivers to receive reduced electricity rates when charging their vehicle during off-peak hours, such as overnight, when less people are utilizing electricity.
The goal of vehicle-grid integration is to reduce EVs’ impact on the grid, and possibly to reduce electricity rates for all ratepayers (including those who do not yet have EVs). EVs can enable utilities to make better use of their infrastructure, can help integrate renewable energy, and can help the grid ensure the optimal flow of electricity.
There are two types of vehicle-grid integration:
Smart Charging or V1G is single-direction charging, when the charging of a vehicle varies in response to grid conditions or pricing. It does not include supplying power from the vehicle to the grid, but includes most of the VGI options employed today.
V2G (vehicle-to-grid) is bidirectional charging and discharging, allowing vehicles to supply stored energy from the vehicle back onto the grid or into a building or local power system.
The State of California organized a VGI Working Group to develop recommendations on the topic. Plug In America participated in this Working Group as the voice of the EV driver. We advocated that drivers’ needs must come first; while VGI may have some economic value to EV drivers, its use must not impact drivers’ ability to use their vehicles as needed. The Working Group estimated that VGI options can provide benefits, but did not examine the costs of implementing them. Accordingly, Plug In America encourages California to exercise restraint in requiring specific VGI solutions, until it is clear that benefits outweigh costs, that the VGI solution will not impair the vehicle’s availability, and that EV drivers will benefit from the VGI solutions.
TOU rates, mentioned above, are an example of a positive VGI solution. The EV driver receives lower electricity rates at off-peak hours, has the option of enrolling in that plan, the rates are typically designed so that excess economic benefit accrues to all ratepayers, and no special charging equipment is required to make use of TOU rates, as all currently available EVs can schedule charging. Plug In America strongly supports EV drivers having the option of TOU pricing as one of the best VGI options. We hope that other VGI options will prove to be as advantageous for EV drivers and for all ratepayers.
The VGI Working Group Final Report developed numerous recommendations including:
- Designating VGI as eligible for California’s energy storage incentive program, with some incentive for one-way smart charging and a larger incentive for full V2G;
- Developing incentives for new construction projects to include EV infrastructure, ensuring that the grid connection of new construction accounts for the EV load;
- Enabling EV owners to receive payment for not charging during peak periods;
- Conducting further research on the net value of VGI;
- Developing pilot projects with EVs providing emergency backup power;
- Expanding public awareness and education related to V2G, with a focus on State and municipal fleets;
- Revising building codes to require more EV-ready parking spaces;
- Streamlining permitting for charging infrastructure; and,
- Ensuring that state transportation electrification goals take priority, with VGI as a possible supplemental value stream.
Plug In America supports the Final Report and looks forward to the next steps in California’s VGI work.