What Is Vehicle-to-Grid?

Vehicle-to-grid (V2G) is a system that lets electric vehicles (EVs) communicate with the public power grid — and even provide electricity back to the grid to meet energy demand.

V2G for vehicle owners

EVs spend much of their time plugged in, either at the owner’s home or in a parking lot. Today’s EVs are able to communicate with the charger, telling it what the current charge of the battery is and how fast the vehicle can accept power. In the future, V2G could safely communicate payment information at public charging stations and unlock additional functionality by creating a cyber-secure gateway between the vehicle and the manufacturer.

Aligning V2G hardware with the HomePlug standard facilitates faster data speeds and improves security by enabling the vehicle to connect to the internet over a house’s internal power lines.

V2G would also allow consumers to provide electricity to their homes from their EVs’ batteries during a power outage. Vehicle owners could even leverage their vehicles’ considerable battery capacity to sell electricity back to the grid during peak load. Users could set a cap on how much power could be drawn to prevent overutilization of the battery, and they could further customize settings to choose to buy back electricity when it’s cheaper and sell to the grid only at peak prices.

V2G for OEMs

V2G technology facilitates a faster and more secure communication pathway between the vehicle and the manufacturer. A direct connection can provide consumers with access to an ecosystem of third-party and OEM-branded applications — opening the door to additional functionality and future revenue opportunities. Additionally, giving OEMs greater control over the charging process will help them optimize charging cycles based on the EV’s specific battery chemistry, which can extend the overall life of the battery and improve consumer appeal. Currently, the “brains” of the charging process reside in the chargers themselves; as OEMs develop V2G, the processing capabilities will move into the car.

V2G for utility providers

While EVs offer enormous potential to reduce CO2 emissions, they are only as clean as the electricity that they use. To achieve a fully green economy, it’s essential to decarbonize electricity production at the source. But replacing fossil fuels with renewable alternatives comes with unique challenges.

The electric grid has to maintain balance between power generation and consumer demand. Fossil fuels can produce electricity when needed, but solar and wind energy are beholden to environmental factors that make them more volatile power sources — that is, solar panels produce more energy during periods of direct sun, and wind turbines produce more energy when it is windy. As the energy industry incorporates more of these alternative sources, grid-scale power storage becomes critical for storing power when it is generated so it can be expended later. V2G technologies provide a solution that offers benefits to vehicle owners, utility companies and OEMs.

Most EV batteries have the capacity to power a typical U.S. home for several days. As more consumers go electric, utility providers could forgo the manufacturing costs associated with high-capacity batteries and instead leverage plugged-in EVs for power storage as they convert a greater portion of their electricity production to renewable sources. This approach would save costs for utility companies and shorten the path to a carbon-neutral world.

The road ahead

One of the biggest challenges with V2G implementation is getting utility companies and vehicle OEMs on the same page. The ISO 15118 V2G protocol addresses this problem by providing a common standard for engineers in both industries.

Aptiv developed a V2G gateway for Volkswagen, called Smart Architecture Charging Interface Device (SACID), that aligns with the V2G standard and ensures a cyber-secure connection using Transport Layer Security — the same protocol that underpins HTTPS web traffic encryption and authentication. SACID is compatible with all regional charging standards and improves functional safety by locking the connection between the plug and the inlet and using three temperature sensors to automatically stop charging if the temperature exceeds a safe limit. SACID contracts have since been awarded by other OEMs.

Aptiv’s portfolio of software and hardware is well equipped to address every aspect of the charging process, from modular inlets with active cooling to busbars that enable high-voltage connections within the battery pack. Our extensive experience with both the brains and the nervous system of the vehicle enables us to ensure that SACID will be compatible with the next generation of high-voltage charging solutions.