Vehicle-to-Grid (V2G): What It Is and What UK Installers Need to Know

Summary

Vehicle-to-Grid sits at the more advanced end of the EV charging spectrum that installers are increasingly asked about, alongside the more established Vehicle-to-Home (V2H) and Vehicle-to-Load (V2L) variants. All three use the same underlying idea — an EV's battery is, functionally, a large mobile battery storage unit that can discharge as well as charge — but they differ in where the discharged power goes: V2L powers a device plugged directly into the car (a camping stove, a power tool), V2H powers the customer's own home during an outage or at peak tariff times, and V2G exports power further, either into the grid itself or as part of a demand-response/grid-balancing service that the vehicle owner is paid to participate in.

For UK tradespeople, the practical entry point today is domestic V2H/V2G bidirectional chargers rather than genuine grid-scale V2G aggregation, which remains largely at trial and early-commercial stage. Nissan's G99 grid-code certification following the University of Nottingham AC bidirectional trial, and the Octopus Energy/BYD consumer V2G bundle launched around the BYD Dolphin, are among the first commercially available UK offerings rather than universal options — most EVs and most chargepoints on the market today are import-only and cannot be retrofitted for bidirectional operation.

The commercial case for V2G rests on time-of-use electricity tariffs: charge the vehicle overnight on a cheap off-peak rate, then either use that stored energy to run the home during the expensive peak period (V2H) or sell it back to the grid at a premium rate during high-demand periods (true V2G). Both models depend on smart tariffs designed for this purpose (Octopus Intelligent, and similar time-of-use products from other suppliers), and the financial benefit is highly dependent on driving pattern, tariff structure, and how much battery capacity the customer is willing to cycle for grid services rather than driving range.

Key Facts

• V2L (Vehicle-to-Load) — power drawn from the vehicle's battery via a domestic-style socket or adapter to run an external device directly; no grid connection or DNO notification implication
• V2H (Vehicle-to-Home) — vehicle battery powers the customer's own household circuits, typically via a hybrid inverter/chargepoint, either to reduce peak-rate grid import or to provide backup power during an outage
• V2G (Vehicle-to-Grid) — vehicle battery exports power back into the public electricity grid, either directly or via participation in a grid-balancing/demand-response scheme, generating revenue or bill credit for the vehicle owner
• Bidirectional chargepoint required — a standard unidirectional EVSE (the vast majority of installed UK chargepoints) cannot provide V2G; a specific bidirectional charger with power electronics capable of DC-AC conversion in both directions is required
• CHAdeMO vs CCS — CHAdeMO was the first connector standard to support bidirectional DC charging in production vehicles (notably Nissan Leaf); CCS (Combined Charging System), now the dominant connector on new European and UK EVs, is gaining bidirectional support via ISO 15118-20 but remains behind CHAdeMO in real-world V2G deployment as of 2026 ****
• ISO 15118 — the vehicle-to-charger communication standard; ISO 15118-20 extends the earlier ISO 15118-2 to support bidirectional power transfer and is the key enabler for CCS-based V2G becoming more widely available
• G98/G99 notification — any generating/exporting equipment connected to the DNO network, including a bidirectional EV charger capable of exporting to the grid, requires notification to the Distributed Network Operator; G98 applies to smaller inverter-connected equipment, G99 to larger or more complex connections — confirm the correct category with the DNO before commissioning ****
• BS 7671 Section 722 — governs EV charging installation requirements generally; a bidirectional installation additionally needs the protection, disconnection, and anti-islanding considerations that apply to any grid-export-capable equipment, similar in principle to a solar PV inverter connection
• Anti-islanding protection — required so the bidirectional charger disconnects from the grid automatically during a mains outage, preventing it from energising a "dead" section of network that DNO engineers may be working on — a safety-critical requirement, not optional
• Smart Export Guarantee (SEG) — the payment mechanism originally designed for small-scale renewable generation exporting to the grid; V2G export payment models are generally separate commercial arrangements with the charger/tariff provider rather than SEG itself, though the underlying export-metering principle is similar
• Battery degradation consideration — cycling an EV battery for V2G/V2H adds additional charge/discharge cycles beyond normal driving use; most current V2G-capable vehicles and warranties account for this, but the customer should understand it's a genuine trade-off, not a free service
• Time-of-use tariffs — V2G/V2H's financial case depends on a tariff with a meaningful price differential between cheap off-peak import and expensive peak periods or premium export payments; without such a tariff, there is little financial incentive to cycle the battery this way
• Current UK domestic hardware availability — a small number of dedicated bidirectional chargers (broadly £4,500–£7,000 fitted as of 2026) are available for home installation, considerably more expensive than a standard unidirectional 7kW chargepoint (£950–£1,400 fitted) ****

Quick Reference Table

Detailed Guidance

What an Installer Actually Needs to Check Before Quoting V2G

The single biggest source of a failed or unsellable V2G quote is assuming compatibility rather than confirming it. Three separate things all need to be true simultaneously:

1. The specific vehicle model and trim supports bidirectional discharge — not all versions of a nominally "V2G-capable" model necessarily support it; battery management system firmware and even market region can affect this
2. A bidirectional charger exists that is compatible with that vehicle's connector and communication protocol (CHAdeMO or CCS/ISO 15118-20) — charger and vehicle protocols must match
3. The customer's intended use case has a commercial or tariff arrangement that makes it worthwhile — hardware alone doesn't generate income; it needs a supporting tariff or aggregator agreement

Because all three of these are changing rapidly, do not quote from memory or from a general "V2G is available now" assumption — check the current compatibility list from the charger manufacturer and the vehicle manufacturer's own technical specification for that exact model year before proceeding.

DNO Notification and Grid Connection

A V2G-capable charger is, from the DNO's perspective, generating/export equipment connected to the network — conceptually similar to a solar PV inverter, even though the "generator" is a car battery rather than a panel. This means:

• Total export capacity of the site (existing solar/battery plus the new bidirectional charger) needs to be assessed against G98 (typically up to 16A per phase, or a similar small-scale threshold) or G99 (larger or more complex connections) requirements
• The DNO must be notified before or immediately after connection, per the applicable notification category — check the current ENA (Energy Networks Association) guidance for the exact process, as this has been simplified in recent years for smaller installations
• Anti-islanding protection must be verified and tested as part of commissioning, exactly as it would be for a grid-tied solar inverter
• This is materially different from a standard unidirectional EV charger installation, which typically only requires the simpler import-only notification process covered in domestic ev charger installation process

Electrical Installation Considerations

BS 7671 Section 722 covers EV charging generally, but a bidirectional installation adds considerations closer to those in part s ev charging and general grid-connected generation guidance:

• The circuit must be designed and protected for power flow in both directions, not just import
• PME earthing considerations that apply to standard EV charging (see pme earthing ev charging) apply equally, and the open-PEN fault protection requirement does not disappear because the installation is bidirectional
• RCD/RCBO protection selection follows the same principles as bs 7671 ev wiring requirements, with the added requirement to confirm the specific bidirectional charger's own internal protection meets the installation's needs
• An Electrical Installation Certificate is required, as for any new EV charging circuit, and the DNO notification paperwork should be retained alongside it

The Realistic Customer Conversation

Given the current state of the UK market, the honest advice to most domestic customers asking about V2G in 2026 is that genuine grid-export V2G remains a small, fast-moving niche rather than a mainstream upgrade path. V2H — using the car battery to reduce the customer's own peak-rate import or provide backup power — is a more achievable and better-supported use case today for most vehicle/charger combinations, and is worth distinguishing clearly from full V2G when discussing options, since the hardware, tariff arrangements, and DNO implications differ.

Where a customer already has a genuinely compatible vehicle and specifically wants V2G rather than V2H, set expectations on cost (materially higher than a standard chargepoint), on the narrower choice of hardware, and on the fact that any income or bill-saving projection depends entirely on a specific tariff or aggregator arrangement that should be confirmed, in writing, before the customer commits to the additional hardware cost.

Solar Integration and V2G/V2H

Many customers asking about V2G are also asking about solar PV integration, and the two are complementary rather than competing — a home with solar generation, a bidirectional charger, and a compatible EV can, in principle, store daytime solar generation in the vehicle battery and use it in the evening (a V2H function), rather than simply diverting excess solar to charge the car as covered in ev charger solar integration. This adds a further layer of system design complexity — the CT clamp, inverter, charger, and (if fitted) a separate home battery all need to coordinate correctly — and is best treated as a bespoke system design job rather than a standard EV charger quote.

Frequently Asked Questions

Does every EV support V2G?

No. Only a limited subset of models currently support bidirectional discharge, and even within a supported model range, not every trim or battery/firmware configuration necessarily does. Always confirm against the manufacturer's current technical specification for the exact model and model year in question — do not assume compatibility from a vehicle simply being electric.

Is a standard 7kW EV charger upgradeable to V2G later?

No. A standard unidirectional chargepoint's power electronics are built for one-directional conversion only; there is no field upgrade path to bidirectional operation. A genuinely bidirectional charger is a different product, purchased and installed as such from the outset.

Does V2G damage the car's battery faster?

It adds additional charge/discharge cycling beyond what normal driving would produce, which is a genuine consideration, though manufacturers offering V2G/V2H products generally design the system (and, where applicable, the warranty terms) to account for this. It is not a reason to avoid V2G outright, but it is a genuine trade-off the customer should understand rather than being told it's cost-free.

What's the difference between V2G and just having a home battery storage system charged by solar?

A home battery (see ev charger solar integration for the solar-diversion context) is a dedicated static storage device with no other function. A V2G/V2H-capable EV uses the vehicle's own battery for the same storage role when it's plugged in, at the cost of a much higher-spec (and currently more expensive) bidirectional charger, and with the constraint that the stored energy isn't available to the car for driving while it's being used to power the home or export to the grid.

Regulations & Standards

• BS 7671:2018+A4:2026, Section 722 — EV charging installation requirements; bidirectional installations must additionally meet export/generation protection requirements

• ISO 15118 (parts 2 and 20) — vehicle-to-charger communication standard; part 20 adds bidirectional power transfer support

• G98/G99 (Energy Networks Association) — DNO notification and connection requirements for generating/export equipment, applicable to grid-exporting bidirectional chargers

• Electricity Safety, Quality and Continuity Regulations 2002 (ESQCR) — general safety framework for equipment connected to the public electricity network

• Smart Export Guarantee (SEG) scheme rules — export payment framework originally for renewable micro-generation; relevant context though most current V2G commercial offers are separate arrangements

• Building Regulations Approved Document S — EV charge point provision for new dwellings; does not currently mandate bidirectional capability

• Energy Networks Association — G98/G99 connection guidance — DNO notification requirements for generating equipment

• Ofgem — Smart Export Guarantee — export payment scheme context

• gov.uk — Electric vehicle smart charging — V1G/smart charging regulatory background relevant to V2G's wider policy context

• BSI — BS 7671 IET Wiring Regulations — Section 722 EV charging requirements

• smart charging requirements — Electric Vehicles (Smart Charge Points) Regulations 2021, the mandatory baseline smart-charging functionality all grant-eligible chargepoints (including bidirectional ones) must meet

• ev charger solar integration — solar PV diversion to EV charging, a complementary but distinct technology from V2G/V2H

• three phase ev supply — higher-power charging infrastructure considerations relevant to sites considering advanced EV charging setups

• pme earthing ev charging — PME/open-PEN protection requirements applicable to any EV charger, including bidirectional units

• bs 7671 ev wiring requirements — Chapter 722 wiring and protection baseline that bidirectional installations build on

• ozev approved installer — installer qualification requirements relevant to any grant-eligible or DNO-notified EV charging work