When neighbourhoods become batteries: Lessons from a Danish V2G village

It is hard not to think about how we normally talk about energy storage. New projects are announced as “battery parks” or “grid‑scale storage”, as if the only way to store electricity is to build big boxes full of cells. 

But we already have massive batteries everywhere. They are parked in driveways, car parks and streets. When people ask, “Why do we need V2G if we’re going to have grid‑scale storage?”, the answer is that cars already “have really big batteries in them”. Building only stationary batteries, while ignoring the ones we have already bought and deployed on wheels, will always be more expensive than it needs to be. 

From an energy‑system perspective, a row of EVs parked at Danish Fælledby is not just a mobility solution. It’s a highly distributed, fast‑responding storage asset that can support the local grid, lower costs and help integrate more renewable power. 

The really interesting part in Copenhagen is that the business case for the project has been built without counting V2G revenue. The numbers already work on solar, grid batteries and grid services. The business case has been built without taking the V2G into account, so any V2G value is on top. That is exactly the kind of robust foundation V2G needs. 

There is a catch.  

Most of today’s V2G offerings are narrow and fragile: a specific vehicle, a specific charge point, a specific country, a specific tariff. If any one of those conditions changes, the service breaks. 

That is not how you build an energy resource at scale. 

If only a few thousand people participate, the system‑level value of V2G is almost close to zero. There is little value in a few thousand people having Vehicle‑to‑Grid. There is incredible value when you have millions of people doing it. 

To get from thousands to millions, the customer experience has to be boringly reliable and incredibly flexible at the same time. 

• It has to “just work” when you plug in, without the driver worrying about protocols and tariffs. 
• The driver must be free to change their vehicle, their charge point, their tariff, or even move country, without losing the basic V2G capability. 

That is only possible if we stop thinking in terms of branded one‑off solutions, and start thinking in terms of interoperable infrastructure. 

Technologically, we can already move power both ways between car and grid. The technology is there, absolutely. What isn’t fully there yet are the standards that make this work across brands, borders and markets. 

In AC V2G, for example, the standards stack has several moving parts: 

• ISO 15118‑20 defines how the vehicle talks to the outside world, but it is not yet mandatory for new vehicles, so most cars don’t support it today. 
• A key piece defining how AC V2G chargers talk to AC V2G‑capable vehicles is only now being finalised, to be published within the next few weeks. 
• On the charge point side, IEC 61851‑1 Edition 4 is expected to apply around the end of this year, unlocking standardised behaviour for these devices. 
• Higher up the chain, grid codes and communication standards (like future grid connection requirements and protocols such as OCPP 2.1 and OpenADR) are still being aligned. 

This is why you cannot yet buy a fully interoperable, plug‑and‑play AC V2G solution today. But are we hard at work on this? Absolutely! 

Zaptec is not just waiting for this to happen. We are actively contributing to the work of Task 53, an international collaboration dedicated to making AC V2G real at scale. 

Task 53 brings together carmakers, charge point manufacturers, energy companies, aggregators and system operators to do three things: 

• Align on how vehicles, chargers, buildings and markets should talk to each other 
• Test real implementations against the evolving standards 
• Identify and close the practical gaps that standards alone don’t solve 

Our role at Zaptec is exactly where Fælledby and the standards story meet: we build the infrastructure that sits between the vehicle and the energy system. 

That means: 

• Chargers with the right hardware foundation for future V2G and flexibility services 
• An integration layer that connects those chargers securely to energy companies, aggregators and building systems 
• Active participation in standardisation and interoperability work, so that what we build in the field matches what is agreed on paper 

We see V2G not as a side feature, but as a natural extension of what our ecosystem already does: turning “boxes on the wall” into a flexible interface between cars, buildings and the grid. 

Zaptec has never been about selling gadgets. Our job is to help build the infrastructure that will let neighbourhoods like Fælledby run on cleaner, smarter power, and to make sure that when the standards land, we are ready. 

That’s why we travel to projects like Fælledby, why we sit in late‑night Task 53 calls, and why we put so much effort into making our chargers and software part of a wider ecosystem. 

V2G will not arrive in a single big launch. It will arrive neighbourhood by neighbourhood, standard by standard, firmware update by firmware update. 

When it does, we intend for Zaptec’s infrastructure to already be there. Tested, connected and ready to help millions of EVs become part of the energy system, not just passengers in it.