What the roaming deal actually changes
GreenFlux has been in this business since 2011, when it was founded in the Netherlands. DKV Mobility bought the company in 2021. Its platform handles the unglamorous part of public charging: the technical connection between networks, the commercial agreements behind it, and the payment processing. The platform currently represents around 20 million charging tokens.
For a driver, the practical result is one card or one app covering more sites. GreenFlux has been adding UK operators since 2024, among them Clenergy EV, Kerb and Osprey. Source is the newest name on that list. The deal follows an earlier arrangement from August 2025, when OVO Charge customers gained access to Source hubs through the OVO app. The GreenFlux agreement pushes the same access out to a much wider set of providers, including continental ones.
Source's build-out: 300 hubs, 3,000 points
The SSE and TotalEnergies joint venture plans up to 3,000 ultra-rapid charging points across roughly 300 hubs in the UK and Ireland over five years. Every site is rated at 150 kW or more and is designed with a minimum of 10 charging bays. Source claims drivers can typically charge in around 15 minutes, depending on the car and conditions.
That 15-minute figure deserves arithmetic. A 77 kWh pack charged from 10 to 80 percent needs 54 kWh. At a constant 150 kW that takes 21.6 minutes. Real charging curves spend most of the session below peak, so a 10–80 percent stop on that pack lands closer to half an hour. Fifteen minutes fits a 20–40 kWh top-up at high average power, which is what most motorway stops actually are.
Fast-charging claims keep getting louder. Li Auto used its 20 October Power Day to present its own 5C battery and an updated i6. A 5C cell is only as good as the charger feeding it, and a 150 kW hub floor is where most of Europe still sits.
Who sets the price at the plug
Roaming works like this: your e-mobility service provider buys access to the network, adds its margin, and bills you. Source sells wholesale access to GreenFlux, and GreenFlux passes it to the providers. Two drivers at the same Source post can therefore pay different rates per kWh, and neither rate is necessarily Source's own ad-hoc tariff. Sometimes the card is cheaper, sometimes contactless is. The app screen is the only reliable answer.
Cost per 100 km, with the assumptions stated
Neither company publishes the roaming rate, so here is the arithmetic with a placeholder. Take a family EV using 20 kWh/100 km. At 25p/kWh on a home tariff that is £5.00 per 100 km. At 79p/kWh, a figure typical of UK ultra-rapid sites, it is £15.80, roughly €18 at 1.15 EUR/GBP. A petrol car at 7 l/100 km and £1.35 per litre needs £9.45 for the same distance.
In that example, public rapid charging costs more per 100 km than petrol. The gap narrows or disappears when most charging happens at home or at work, which is why the savings arithmetic in our charging cost calculator depends so heavily on the home-to-public kWh split. Roaming access does not change any of that. It removes an account, not a cost.
How 300 planned hubs compare with the sites we track
Our supercharger database currently holds 483 fast-charging locations across Europe with their prices attached, mapped on the supercharger map. Source's planned 300 hubs is about 62 percent of every site we have catalogued, in a single country pair. GreenFlux's 1.2 million charge points number is a different shape of data: it includes AC and destination charging, so it cannot be set against a rapid-hub count. The cheapest locations page shows how wide the price spread already is between networks, and the UK ultra-rapid band sits at the expensive end of it.
What to do before a UK trip
Check your provider's app for Source sites and for the rate it charges there before you rely on the card. Keep a contactless payment backup, because roaming agreements fail at the worst moments and a hub with 10 bays is still a hub with one card reader. If your car charges at 50 kW, the 150 kW floor brings nothing; the minimum bay count does, because queues at motorway sites are the real time cost. And if you drive a fleet car with a DKV card, GreenFlux's parent company is the reason that card reaches further than it did a few years ago.
GreenFlux's release puts Source inside a roaming platform of 1.2 million charge points. Neither company states how many of the planned 300 Source hubs are open today, or what a roaming kWh will cost at them.