Last month I wrote about why UK charging operators keep losing money despite record EV sales. The short version: pence-per-kWh margin can't carry hardware that sits idle most of the day, and future-proofing a site comes down to four decisions made before the first cable is pulled. The fourth was a revenue layer of storage and software that pays the bills before drive-up demand does.
That piece named the fourth decision. It didn't explain how to build it. This is the how.
A Parked EV Is Not a Cost Centre
Fleet depots are unusually well suited to this, because the vehicles are parked for hours at a stretch on a predictable schedule. That's exactly the profile grid operators are trying to procure when they buy flexibility. A bus sat in a depot overnight, or a delivery van between routes, is doing nothing for the business it belongs to and, on a one-way charger, nothing for the business that installed the charger either.
If the underlying concepts need unpacking: what vehicle-to-grid actually is, what a virtual power plant aggregates, and how energy arbitrage works. This article assumes you know the definitions and want the mechanics: which markets exist, what each one requires, and why most sites can't act on them yet.
Four Markets, Four Registration Paths
None of what follows is theoretical or new policy. Each of these is a market that already exists in Great Britain, with its own registration process and its own hardware requirements.
Wholesale market arbitrage
Charge during low or negative price periods, discharge or reduce load when prices spike, executed automatically against Elexon's day-ahead and intraday price data. This requires on-site battery storage or dispatchable charging load, and an EMS that can act on price forecasts without a human in the loop. It's the simplest of the four to get into and the easiest to explain to a finance director.
Frequency response
NESO procures services like Dynamic Containment and Dynamic Regulation to keep grid frequency inside its operating band, and some of these require a response inside 150 milliseconds. That response speed rules out manual dispatch entirely. It has to be automated, and the EMS has to be fast enough and reliable enough to be trusted with it.
Capacity Market
The Capacity Market runs T-4 (four years ahead) and T-1 (one year ahead) auctions where an asset commits to delivering firm power during system stress events, in exchange for a capacity payment. This is a longer-horizon commitment than the other three: it rewards proven, predictable availability rather than active trading, which suits a site with a stable, well-documented duty cycle.
V2G, vehicle-to-grid
Exporting energy from parked EVs during high-price periods over bidirectional CCS2 and the ISO 15118-20 protocol. This is the one that depends on the vehicle as much as the charger: both ends need to support bidirectional power flow, and the EMS needs to schedule import and export in a way that protects the battery's warranty terms rather than cycling it harder than the manufacturer allows.
A parked EV in a designated V2G bay. The vehicle isn't idle between sessions, it's a registered asset the site can dispatch.
Why Most Sites Can't Do This Today
The gap isn't market access. It's what's actually installed. Most public and depot chargers only import power, so V2G and export-side arbitrage are off the table regardless of what the vehicle can do. Most sites don't run an EMS built to register and act across four markets with four different response requirements, so even where the hardware could support it, nothing is watching the price signals or the frequency events closely enough to act on them. And a lot of grid connections were sized only for charging load, with no headroom for export in the other direction.
This is the same argument as the grid connection and modular hardware decisions from the earlier piece, applied to the revenue side instead of the demand side. A connection or an architecture that only ever expected power to flow one way has no path to earning from the other three.
| Market | What it requires | Revenue mechanism |
|---|---|---|
| Wholesale arbitrage | BESS or dispatchable load, price-aware EMS | Buy low, sell or avoid high |
| Frequency response | Sub-150ms automated response | Availability and performance payments |
| Capacity Market | Proven, predictable firm capacity | Capacity payments, T-4 / T-1 |
| V2G export | Bidirectional charger and vehicle, ISO 15118-20 | Export during high-price periods |
A Different Business Model, Not Just a New Revenue Line
None of this revenue has to stay with the CPO. Sharing a portion of wholesale arbitrage, frequency response or V2G export income with the vehicle owner turns a single pay-per-kWh relationship into a shared-upside one, which is a structurally different business model from the one squeezing most operators today, not just a bolt-on revenue line.
This matters most where the fleet is large enough that even a modest per-vehicle share adds up, and where the vehicles are parked centrally and predictably. Organisations running fleets at the scale of Royal Mail's delivery vans, Network Rail's maintenance and works vehicles, or National Grid's own field and engineer fleet are exactly this profile. For a fleet that size, V2G and flexibility revenue sharing isn't a marginal perk, it's a real budget line, and the social case (less strain on the grid at peak, better use of renewable generation, emissions reduction from smarter charging behaviour) sits right alongside the economic one.
This Is What Neutron Grid EMS Is Built to Do
Neutron Grid EMS integrates directly with these four markets: automated arbitrage against Elexon's price forecasts, sub-150ms response to NESO frequency events, Capacity Market auction registration, and a Fleet V2G API that schedules import and export automatically while protecting battery health. It runs alongside Electron CMS, so the same platform that manages the charge points also manages what they earn when nobody's plugged in. Full detail on the trading side is on the Platform page.
Frequently Asked Questions
What is the "fourth decision" in future-proof EV charging infrastructure?
It's the revenue layer: a way for a charging site to earn money from idle capacity during the years before drive-up demand alone covers its costs. The first three decisions (modular hardware, a grid connection sized for headroom, and a siting strategy that isn't locked to one vehicle type) determine whether a site can serve its fleet. The fourth determines whether the business survives long enough for that to matter.
Which UK electricity markets can an EV charging site register for revenue?
Four are live today: wholesale market arbitrage against Elexon's day-ahead and intraday price data, NESO frequency response services such as Dynamic Containment and Dynamic Regulation, the Capacity Market's T-4 and T-1 auctions for firm power commitments, and vehicle-to-grid (V2G) export over ISO 15118-20 and bidirectional CCS2.
What hardware does V2G and grid-revenue participation actually require?
Bidirectional charging hardware that can both import and export power, a vehicle and charger pairing that supports ISO 15118-20, and an energy management system fast enough to act on multiple markets at once, including frequency events that require a response inside 150 milliseconds. Most existing one-way chargers and DNO connections sized only for import cannot do this without retrofitting or replacement.
Why can't most existing UK charging sites do this today?
Not because the markets are closed. It's a hardware and software gap: most installed chargers only import power, most sites don't run an EMS capable of registering and acting across four different markets with different response requirements, and many grid connections were sized only for charging load, not for export as well.
Grid EMS V2G: ISO 15118-20 NESO Frequency Response Capacity Market RegistrationIf You're Running 100+ Vans or HGVs, This Is Where the Numbers Stop Being Marginal
Choose the right technology and revenue architecture before you plan electrification, not after the depot's already built around the wrong one. Send us your site and vehicle mix and our engineering team will model what a revenue layer looks like for it.
Talk to the engineering team