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Your electric vehicles spend a large part of the day parked. At the charger, at the depot, on the car park. The batteries are full, or at least not empty. With regular charging, that is idle capacity: power goes in and stays there. Bidirectional charging reverses the flow. Power can move not only into the battery but also back out. That turns every parked vehicle into a potential energy source for your building, your business park or even the public grid.

TL;DR

Bidirectional charging lets electric vehicles feed power back instead of only drawing it. That opens possibilities well beyond transport.

  • With V2B (Vehicle-to-Building), the vehicle feeds your premises, shaving demand peaks and lowering network charges.
  • With V2G (Vehicle-to-Grid), you export to the grid and can earn revenue through flexibility markets.
  • The technology requires a bidirectional charger, a compatible vehicle and a communication standard (ISO 15118-20) that speaks both ways.
  • Without centralised control, each vehicle acts on its own. Only with an EMS does bidirectional charging become a coordinated strategy.
  • The business case strengthens as grid congestion increases, dynamic tariffs become the norm and battery capacity in vehicles grows.

Bidirectional charging is not a future concept. The technology works, the standards exist and the first businesses are already applying it.

What is bidirectional charging?

Bidirectional charging means an electric vehicle can not only draw power from the grid but also feed power back. The energy flow runs in two directions: from grid to battery and from battery back to a building, a local energy system or the public electricity grid.

With regular (unidirectional) charging, the vehicle is purely a consumer. The charger supplies power, the battery absorbs it, and that is it. Bidirectional charging adds a second function: the vehicle also becomes an energy source. The battery that normally only delivers kilometres can now deliver kilowatt hours to other consumers on the same site.

The principle is comparable to a stationary battery storage system, but mobile. An electric HGV with a battery of 300 to 600 kWh has more storage capacity than many stationary battery systems. A fleet of twenty vehicles already represents several megawatt hours of available capacity, provided that capacity is accessible at the right moment.

Batterijopslagsysteem naast een industriële productiehal met elektrische bestelbussen aan de laadpaal

The variants: V2B, V2G, V2L and V2X

Bidirectional charging is an umbrella term. The applications differ in where the returned power ends up.

  • V2B (Vehicle-to-Building) keeps the power behind your own meter. The vehicle feeds back to the building or the charging area where it is parked. This is the most direct application: you shave demand peaks with your vehicle battery rather than with grid power. No export, no coordination with the grid operator. For many businesses, V2B is the logical first step.
  • V2G (Vehicle-to-Grid) goes further. Here the vehicle feeds power back to the public electricity grid. That enables trading: you can offer flexibility at moments of grid scarcity and receive a payment for it. V2G does require a contract with an energy supplier or aggregator and coordination with the grid operator.
  • V2L (Vehicle-to-Load) is the smallest-scale variant. The vehicle powers a device or a temporary installation via a socket on the vehicle itself. Useful on a construction site or at an event, but limited for structural business use.
  • V2X (Vehicle-to-Everything) is the overarching concept that covers all these variants. In practice, manufacturers and policymakers use V2X when referring to the broad potential of bidirectional charging, regardless of the specific application.

For most business applications, V2B and V2G are the most relevant. V2B delivers direct savings on the energy bill. V2G adds a revenue stream but also brings more complexity in contracts and coordination.

What do you need for bidirectional charging?

Bidirectional charging requires three components that work together: the vehicle, the charger and the communication layer between them.

  • A compatible vehicle. Not every electric vehicle can feed power back. The battery, the inverter and the vehicle software must all support reverse power flow. The range of compatible models is growing, but it varies considerably by manufacturer and model. When purchasing or leasing, it is worth checking the specifications on this point explicitly.
  • A bidirectional charger. A standard smart charger sends power in one direction only. For bidirectional charging you need a charger with a built-in inverter that can handle power flow in both directions. These chargers are more expensive than unidirectional alternatives, but the premium is falling as supply increases.
  • Communication via ISO 15118-20. The charger and the vehicle need to communicate about the direction and capacity of the power flow. The standard for this is ISO 15118-20, which specifically supports bidirectional communication. The European AFIR regulation requires newly installed DC charge points in the EU to be technically prepared for this standard.

What does bidirectional charging deliver for businesses?

The business case for bidirectional charging varies by situation, but it turns on three things: peak reduction, flexibility value and deferred investment.

  • Shaving demand peaks. At moments when your building or depot draws heavy power, a vehicle battery can step in. That lowers your peak demand on the grid, and with it your network charges. The mechanism is identical to peak shaving with a stationary battery, but you are using capacity that is already there.
  • Monetising flexibility. With V2G you can feed power back at moments when the grid is tight. There is a payment in return. That payment grows as grid congestion increases and the demand for flexibility rises. Your fleet becomes an asset that not only drives but also earns while it stands still.
  • Deferring grid reinforcement. Businesses whose energy demand is growing (more charge points, more production, more cooling) run into the limits of their grid connection. Bidirectional charging gives you additional headroom: rather than applying for a heavier connection, you deploy the storage capacity in your vehicles to absorb peaks locally. That saves both waiting time and investment.

The value depends directly on how well you coordinate the reverse power flow. One vehicle feeding back occasionally is an interesting experiment. An entire fleet charging and discharging in coordination, based on energy prices, consumption patterns and grid capacity, is a serious financial lever.

Why bidirectional charging does not work without control

Adding bidirectional charging to a depot or business premises is not simply a matter of installing the right chargers. Without centralised control, the coordination is missing.

A vehicle feeding back while another vehicle charges simultaneously causes unnecessarily high currents on your internal network. A vehicle that discharged in the morning and then lacks sufficient charge for its scheduled route is an operational problem. And a fleet that feeds back to the grid in an uncoordinated fashion generates less flexibility value than one that responds collectively at the right moment.

This is where energy management comes in. An EMS that controls your vehicles, chargers, solar panels and any battery storage as a single system determines the optimal allocation at each moment: which vehicle charges, which vehicle feeds back, and how much power flows in each direction. She factors in departure schedules, energy prices, the status of your grid connection and the state of charge of each vehicle.

Tibo Energy works with logistics operators such as Lidl, GXO, Van den Broek Logistics and LVS on precisely this challenge: intelligently coordinating dynamic charging at depots where grid capacity is limited and every kilowatt hour counts.

Find out what bidirectional charging delivers for your site

Want to know what bidirectional charging combined with an EMS could deliver at your location? Book a demo and we will show you how it works in practice.

Frequently asked questions

Smart charging controls the timing and power level at which a vehicle charges, for example based on energy prices or available grid capacity. The power flows in one direction only: from grid to battery. Bidirectional charging adds the reverse direction: the vehicle can also export power. Smart charging is therefore a prerequisite for bidirectional charging, and in practice the two converge in a single system.

Additional charge and discharge cycles do cause wear, but the impact depends heavily on how the process is managed. Shallow, well-timed cycles have a limited effect on battery lifespan. An EMS that accounts for the state of charge and usage profile of each vehicle keeps degradation to a level that is acceptable for most business applications.

No. The vehicle must have both the hardware (an inverter that works in both directions) and the software on board to support reverse power flow. This varies considerably by manufacturer and model. The range is growing, partly because ISO 15118-20 is being adopted widely, but always check the specifications when purchasing or leasing.

Yes. A standard smart charger can only supply power, not receive it. For bidirectional charging you need a charger fitted with a bidirectional inverter. The AFIR regulation requires newly installed DC charge points in the EU to be prepared for bidirectional communication.

With V2B, the returned power stays behind your own meter: the vehicle feeds your building or charging area. With V2G, the power goes to the public grid, which enables trading on flexibility markets but also requires coordination with the grid operator and a suitable contract. Many businesses start with V2B because of its lower complexity and move to V2G once volumes and contracts justify it.

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