V2X, meaning vehicle-to-everything, is the overarching term for transferring the electricity stored in electric vehicle (EV) batteries to the grid, buildings, houses, and other energy-consuming destinations. V2X requires bi-directional energy flow from the charger to the vehicle and bi- or unidirectional flow from the charger to the destination, depending on the use case. Although there have been a number of successful V2X pilots, it is still considered an emerging technology.
How are V2G, V2B, V2H, V2V, V2L and V2H Different from V2X?
These terms designate the different destinations for the electricity drawn from the connected EV battery. The use cases are:
- V2G: Vehicle-to-grid, where the power grid uses stored EV electricity to balance loads during high-demand periods, avoids the need to increase generation capacity to meet increased demand to power EVs. It was the first use case for V2X and the terms are often used interchangeably.
- V2B: Vehicle-to-building transfers power from parked EVs to the building’s power management system during peak load times or power outages while ensuring that the EVs will have sufficient charge at the end of the workday.
- V2H: Vehicle-to-home works like V2B, but at a much smaller scale, to provide electricity to the home for up to several days during power outages.
- V2V: Vehicle-to-vehicle is a way to transfer power between EVs, including cars, trucks, buses, scooters, and electric bicycles.
- V2L: Vehicle-to-load means that using a DC-to-AC inverter and AC power outlets, the EV battery can power plug-in electric devices, equipment, and appliances.
- V2F: Vehicle-to-farm encompasses V2H and V2L types of applications in a farm environment.
How is V2X Different from Smart Charging?
EV smart charging ensures the safe delivery of power to EVs without compromising on delivering electricity to offices, campuses, commercial locations and homes. It is a software-based function that uses intelligence and communications between the charger, the EV, and the charging operator to balance demand placed on the energy grid by slowing or disabling EV charging during peak demand periods. This helps balance the grid overall and, where available, takes advantage of flexible energy markets.
What technology is required for V2X?
V2X requires:
- Vehicle enabled for V2G
- Bidirectional charger
- Communications link between the charger and the vehicle using a V2G-compliant communications protocols ISO 15118 and OCPP 2.0.1
- Smart charging control system that supports V2G
A vehicle that can support V2X can export energy from its battery to the charger without doing damage to either and is equipped to do so. The earliest V2G-enabled EVs on the market support the ChaDeMo protocol. As other protocols commonly in use in the Americas and Europe – including ISO 15118 and OCPP 2.0.1 – mature in their support of V2X, more carmakers will be comfortable adopting the technology.
Does V2X affect EV battery life?
Whether or not V2X is involved, discharging a battery below 20% of cell capacity and overcharging past 100% can damage the battery. The question is whether the frequent charging and discharging of batteries for V2X applications will cause damage, as long as the battery is not over-or under-charged. One study, the VIGIL project at the University of Aston in the UK, showed that keeping the charge between 20% and 80% can actually extend the life of the battery pack.
What is the value of V2X?
With the electrification of transportation, EVs – especially fleet EVs with centralized charging depots or office buildings and campuses with centralized charging infrastructure – could potentially become part of the decarbonization of the grid. EVs, through bidirectional charging, give stored power back to the grid when it’s needed rather than bringing new power generation sources online, and draw power off the grid for charging at off-peak times.
This envisions the interconnection of two ecosystems, transportation and power, working together to help the planet. Factor in the fact that millions of EVs – battery storage on wheels – will be on the road at the end of this decade, and the theoretical becomes the possible.
V2G can also enable individual EV owners to engage in providing power to the grid at peak times while using power to charge the EV during off-peak times. Scenarios include homeowners earning money for power sent to the grid or saving money by only charging at off-peak times when rates are lower. EVs with V2H can power an entire home during a utility outage. For how long is determined by battery capacity, level of charge, and the load from the home. V2L provides power away from the grid. Applications range from using a small refrigerator and lighting while camping to powering tools on a construction site.
