V2G - Vehicle-to-Grid

V2G enables two-way energy flow, allowing EVs to charge from the grid and feed excess energy back during peak demand. Discover how it can benefit both the grid and EV owners.

What if charging an EV was more than a one-way process? What if vehicles and chargers could make micro-adjustments during each session, in such a way as to actually give back to the energy grid in times of need?

Would that result in a bunch of empty EVs? Or would it mean more robust grid security and smarter, more intelligent charging?

Welcome to the world of V2G charging, where interconnected software makes ‘vehicle-to-grid’ energy transfer possible – and does so in a way that’s mutually beneficial for drivers, energy suppliers, and Charge Point Operators (CPOs).

What is V2G technology?

Vehicle-to-Grid charging is the term given to a new kind of bidirectional charging technology – one designed to help alleviate grid strain as more and more drivers switch over to electric vehicles.

Let’s unpack that quickly. If you imagine what’s going on behind the scenes with any normal charging session, it’s pretty easy to understand the key transaction taking place. The EV is asking a simple question of the grid: Can I have some electricity?

But as more and more vehicles connect, local energy suppliers face a challenge: mitigating overuse and ensuring there’s enough electricity to go around. V2G, then, turns that simple ask into a two-way conversation. It facilitates a situation where, so long as the vehicle is charged to a given percentage by the time the driver needs to use it, the EV can give some of its battery back to the energy grid at key moments of peak strain.

In short? V2G technology enables a unilateral charging ecosystem – one in which EVs can give back to the energy grid instead of solely taking from it.

How does V2G work?

A V2G charger turns connected EVs into a source of backup energy for the grid by discharging electricity from the battery at key moments. Using intelligent algorithms, energy suppliers effectively take a look at all the vehicles connected to compatible chargers on the network and make small adjustments in the direction of power flow. In peak times, for example, when energy supply is being challenged, the grid can opt to draw small amounts of power from the batteries of a host of connected cars which, when combined, amount to a significant resource that can be supplied elsewhere.

Scale is an important part of this. V2G operates on a principle of micro adjustments happening across a swathe of vehicles – so it’s never a situation where one person’s car becomes responsible for supplying everyone else’s power. And, in the main, the energy flow heading into the vehicle’s battery will massively outweigh that going in the other direction.

V2G charging requires charging hardware and software capable of offering the service. That means vehicles, chargers, and the platforms that power them.

Right now, there’s work taking place to standardise these protocols in a bid to make offering V2G more straightforward for CPOs, eMobility Service Providers, and energy suppliers. ISO 15118, for example, is a new industry standard designed to ensure all technology providers are singing from the same hymn sheet with their V2G integrations.

What is ISO 15118?

ISO 15118’s official title is “Road Vehicles – Vehicle to Grid Communication Interface.” Its purpose is to standardise the way vehicles, charging stations and the energy grid communicate – in a way that makes charging more convenient, safe and smart for everyone involved. It’s a joint project between the International Organization for Standardization and the International Electrotechnical Commission (IEC), and is designed to allow EV charging that communicates with the energy grid – helping vehicles form a more symbiotic, two-way relationship with energy supplies.

Will V2G drain my EV’s battery?

No! One of the most important things to remember about V2G is that it’s not designed to drain people’s batteries. Instead, it just siphons some excess power off the top, from anything over and above what the driver needs.

To that end, V2G systems are designed to put the driver in control – they’ll set a specific percentage of charge they want to achieve, and the time they’ll need the car by. Vehicle-to-Grid algorithms will ensure this criteria is met, but they’ll send some energy back to the grid around those requirements.

Because of this, V2G systems are great for home charging setups – or any kind of EV charging situation where the vehicle is plugged in for longer than it needs to reach a typical 80% charge.

What is V2H?

V2H stands for Vehicle-to-Home, which is an offshoot of the same technology V2G uses. Here though, EV drivers could use their connected EV to help power their home – saving them money in the process.

The way this works is that your home’s energy supply would charge your vehicle while energy prices are low, and then the inverse would happen during peak (more expensive) hours. V2H requires a home battery solution, alongside a compatible vehicle and chargers.

The benefits of V2G Technology

V2G charging is a big step forward for the eMobility industry because it enables a more robust ecosystem, where intelligent tools can create a less parasocial relationship between vehicles and the electricity grid.

Here are some of the key benefits:

Grid stabilisation

Vehicle-to-Grid’s main purpose is in helping to manage grid demand. As more and more drivers switch to electric vehicles, the demand we put on energy supplies is going to increase massively. V2G is one strategy among many for managing that demand growth, as it effectively turns parked EVs into overflow power plants for the grid as a whole.

Cost saving

Giving back to the energy grid can also help reduce costs to those paying for energy. Depending on the agreements in place, homeowners and CPOs – like (service station, parking lot, and residential development owners) might benefit financially from V2G technology via deals that reimburse users for the energy they send back to the grid.

Increased use of renewable energy

When vehicles are capable of giving energy back to the grid, they count as a renewable source of energy. That’s because those extra kilowatts don’t need to be generated through non-sustainable sources (like fossil fuels). The less we rely on spinning up generators in times of peak energy demand, the greener our overall electricity ecosystem becomes.

Environmental sustainability

That V2G technology exists is a testament to the industry’s interest in promoting and securing a greener future. It will go some way to alleviating grid strain, which will make energy availability more reliable, and that will make moving to electric vehicles a more viable proposition for many.

In other words? This is an upward spiral – a positive reinforcement loop – where more V2G-enabled infrastructure will make it easier for more EVs to join the grid, which will, in turn, mean more V2G-enabled infrastructure.

Spirii’s take on V2G and the future

Here at Spirii, we’re really excited about V2G because of what it represents: a leap towards a more robust and reliable grid infrastructure – and a more seamless EV driving experience as a result.

But Vehicle-to-Grid charging is still in its infancy. As with any new technology, it requires adoption, compatible hardware and software, and a degree of reliability that can make uptake seem like a no-brainer. Right now, V2G’s rollout is reliant on a couple of key developments:

V2G compatible cars

You can’t offer or use V2G charging with any EV – they need to be compatible. Remember ISO 15118 that we talked about earlier? This is where it and similar industry standards come in, forging the way for all new vehicles and chargers to handle V2G technology in a unified way. Most major EV manufacturers now are either making V2G-compatible cars – or already have some on the market.

Pilot projects

At the time of writing, there are a bunch of Vehicle-to-Grid chargers and software being rolled out and tested as part of pilot projects. What’s tricky is that things like regional differences, local legislation, energy grid deals, and general ecosystem readiness mean that there’s not really a one-size-fits-all approach to this. Instead, V2G is being put through its paces in ways

At Spirii, we see ourselves as a core part of eMobility’s future. We know how important it is for software and platform-based architecture to form the backbone of tomorrow’s charging infrastructure. Hardware is always an important part of the puzzle, but software is what allows CPOs and drivers to benefit from retroactive feature additions through software updates.

That’s why we’re working on our own V2G rollout as part of wider, ongoing improvements to every feature that CPOs, drivers and everyone in between will benefit from. Watch this space.

V2G charging FAQs

What is V2G?

V2G stands for "Vehicle-to-Grid." It's a technology that allows EVs to not only draw power from the electrical grid to charge their batteries, but also to feed power back into the grid when needed. This bidirectional flow of electricity enables EVs to act as mobile energy storage units, helping to balance the power grid and provide additional energy during peak demand periods.

What is a V2G charger?

A V2G charger is a charging station that supports two-way power flow between an electric vehicle and the power grid. Unlike standard EV chargers that only send power from the grid to the vehicle, V2G chargers can also draw power from the vehicle's battery and feed it back into the grid when required. These chargers need specific hardware and software to manage the bidirectional flow of electricity safely and efficiently.

Which cars support V2G?

As of early 2024, only a limited number of electric vehicles support V2G technology. Some notable examples include:

  • Nissan Leaf (certain models)
  • Mitsubishi Outlander PHEV
  • Hyundai Ioniq 5
  • Kia EV6
  • Ford F-150 Lightning (with an appropriate home integration system

It's important to note that V2G compatibility often depends not just on the vehicle model, but also on the specific version, software, and sometimes additional hardware. The list of V2G-compatible vehicles is only set to expand.