V2G Procurement Guide for Fleets and Utilities 2026: Bidirectional Chargers, ISO 15118-20, CHAdeMO, ROI

1. What V2G procurement actually buys you

Vehicle-to-grid (V2G) procurement delivers four things in one tender: a bidirectional DC charger (typically 15–60 kW per port for depot use, 100–240 kW for utility-scale installations), a communication stack that supports ISO 15118-20 or CHAdeMO bidirectional profiles, a utility interconnection certificate (G99 in the UK, Rule 21 interconnection agreement in California, VDE-AR-N 4105 in Germany), and an aggregation contract that monetises frequency regulation, peak shaving or demand response. Residential V2G (Wallbox Quasar, Zaptec Pro V2G) is a different product class; fleet and utility buyers should treat it as adjacent benchmark data, not a direct substitute.

2. V2G vs V2H vs V2L: scope the project correctly

The three bidirectional modes solve different problems and use different hardware. Mis-scoping is the single most common procurement error we see in fleet RFQs.

V2G is the only mode that generates grid revenue. V2H reduces the home electricity bill. V2L is a convenience feature. Fleet depots almost always want V2G; residential buyers almost always want V2H.

3. The bidirectional protocol stack: ISO 15118-20, CHAdeMO, OCPP 2.1 V2X

Three protocols matter for 2026 procurement. ISO 15118-20:2022 is the forward-looking standard: it adds bidirectional power transfer over both CCS2 and (optionally) CHAdeMO, mutual TLS 1.3 authentication, WLAN high-level communication, and multi-contract Plug & Charge. CHAdeMO has been natively bidirectional since 2012 (its origin was Japan’s post-Fukushima grid resilience programme) and remains the dominant bidirectional protocol on Nissan Leaf, Mitsubishi Outlander PHEV and Japanese market vehicles. OCPP 2.1 introduces V2X extensions in the charger-to-backend layer, letting the aggregator schedule bidirectional sessions, cap discharge depth and settle energy transactions.

Practical procurement rule: specify ISO 15118-20 and OCPP 2.1 as mandatory, and require CHAdeMO bidirectional as a configurable option if your fleet includes Nissan or Mitsubishi models or you need Japan-market compatibility. The Numbat charger is currently the only commercial unit that natively supports CHAdeMO and CCS2 in the same cabinet; Watt&Well has published tested bidirectional operation on the Kia EV9 and Nissan Leaf.

4. Fleet-type recommendation matrix

The right V2G configuration depends on fleet duty cycle, dwell time at the depot, and the local revenue stack. The matrix below is calibrated to European and North American markets as of October 2026.

5. Economic model: ROI by use case

Public pilots and aggregator disclosures from 2023–2026 give a defensible range. Fleet grid revenue is a function of three variables: available plug-in hours per year, local ancillary-service price, and discharge throughput allowed by the OEM warranty. The ranges below are the per-vehicle gross revenue reported in verified pilots, before the depot’s share of aggregator fees.

Capital cost benchmarks: a 50 kW CCS bidirectional DC charger lists at USD 5,000–15,000, roughly 1.5–2× the price of a unidirectional 50 kW DC unit. UK installed cost for a residential-grade V2G charger is GBP 4,000–7,000 versus GBP 800–1,200 for a standard smart AC wallbox. Utility service upgrades for a five-EV depot typically run USD 8,000–10,000 on top of the charger itself. For most depot fleets the payback window is 3–5 years; for school buses with summer idle it compresses to 12–24 months.

6. Grid interconnection: G99, Rule 21, VDE-AR-N 4105

You cannot export energy to the grid without the local DNO or utility signing off on the interconnection. The three regimes buyers encounter most often:

7. Hardware shortlist: commercial bidirectional chargers in 2026

The commercial V2G hardware market is still narrow. These are the products with verifiable bidirectional operation and fleet-grade references as of October 2026.

8. HG Power V2G Bidirectional Series: 15–240 kW

The HG Power V2G Bidirectional Series spans 15 kW (depot overnight) to 240 kW (utility-scale and transit-bus applications). It is designed for fleet integrators and utility DER programmes and sits inside the same 9-series HG Power product family as the Galaxy AC, Stellar AC/DC, Genesis DC Integrated, Aurora Split and Deepsea / Glacier liquid-cooled platforms.

Buyers running pilot-scale deployments typically start with 2–4 units of 30 or 60 kW, pair them with an aggregator contract, and expand to full depot coverage after the first revenue cycle.

9. Six RFQ clauses to put in your V2G tender

1. Bidirectional protocol: "Charger shall support ISO 15118-20:2022 bidirectional power transfer over CCS2. CHAdeMO bidirectional (BiDi) shall be a configurable option. Supplier shall declare current firmware version and ISO 15118-20 certification body."
2. OCPP V2X: "Charger shall implement OCPP 2.0.1J (IEC 63584) at minimum, with a documented upgrade path to OCPP 2.1 V2X extensions for aggregator dispatch, discharge-depth capping and bidirectional energy settlement."
3. Grid interconnection: "Charger shall hold a valid Type Tested approval for the destination grid code (G99 for UK, UL 1741 SB + IEEE 1547-2018 for US, VDE-AR-N 4105 or 4110 for Germany). Approval reference numbers to be supplied with the bid."
4. Round-trip efficiency: "Supplier shall declare round-trip efficiency (grid → battery → grid) at 25% and 100% nameplate power, measured per IEC 61851-23:2023 or equivalent, with test report attached."
5. Cybersecurity: "Charger shall support mutual TLS 1.3 authentication per ISO 15118-20, X.509 certificate rotation under Hubject V2G Root CA or equivalent PKI, and secure OTA firmware update signed by the OEM."
6. Warranty and cycle life: "Supplier shall warrant the bidirectional power module for a minimum of 5 years or 10,000 full bidirectional cycles, whichever occurs first, and shall declare mean time between failures (MTBF) for the power stack."

10. Pilot evidence: LA AFB, NYC schools, UK depots

Three pilots anchor the business case in 2026 procurement conversations. Los Angeles Air Force Base ran a 40-vehicle non-tactical fleet trial with roughly half the vehicles configured for V2G, demonstrating frequency regulation revenue in the CAISO market. New York City deployed school-bus V2G at multiple districts, with Efficiency Maine and NYSERDA publishing per-bus revenue figures above USD 10,000 per summer. UK fleet guides (Octopus Electroverse, Cenex) document residential and small-fleet V2G revenue in the Octopus Flux and Intelligent Octopus tariffs, pointing to GBP 400–900 per vehicle per year in bill savings for V2H and higher figures where the aggregator captures FFR revenue.

11. Deployment risks and mitigations

12. FAQ

Q1. What is V2G?

V2G (vehicle-to-grid) is a bidirectional charging mode where an EV discharges energy back into the utility grid through a bidirectional DC charger, under utility interconnection approval and typically through an aggregator contract that monetises frequency regulation, peak shaving or demand response.

Q2. What is the difference between V2G, V2H and V2L?

V2L powers appliances directly from the car at 1.5–3.6 kW; V2H powers a home panel through a bidirectional wallbox at 7.4–11 kW; V2G exports energy to the utility grid at 11–240 kW and generates grid revenue. Fleet depots almost always want V2G.

Q3. How much does a V2G charger cost?

A 50 kW CCS bidirectional DC charger costs USD 5,000–15,000, roughly 1.5–2× a comparable unidirectional unit. UK installed cost for a residential-grade V2G charger is GBP 4,000–7,000. Utility service upgrades for a five-EV depot typically add USD 8,000–10,000.

Q4. Which cars support V2G?

Nissan Leaf and Mitsubishi Outlander PHEV support CHAdeMO bidirectional natively. Kia EV9, Hyundai Ioniq 5 and Ioniq 6 (model-year dependent), Volvo EX90 and Ford F-150 Lightning (V2H) support ISO 15118-20 or vendor bidirectional profiles. Confirm per vehicle VIN before specifying the RFQ.

Q5. Is V2G worth it financially for fleets?

Verified pilots report USD 1,000–5,000 gross revenue per vehicle per year for light-duty fleets, rising above USD 10,000 for school buses with long summer idle. Payback is typically 3–5 years for depot fleets and 12–24 months for school-bus V2G.

Q6. What is a G99 certificate?

G99 is the UK Engineering Recommendation that governs grid connection of generation sources above 16 A per phase. V2G chargers above 3.68 kW typically require G99 Type Tested approval from the local DNO; smaller units fall under G98.

Q7. Does ISO 15118-20 require Plug & Charge for V2G?

ISO 15118-20 supports Plug & Charge contract-based authorisation and bidirectional energy transactions in the same session, but the two features can be deployed independently. V2G can run with EIM (External Identification Means) authorisation; PnC becomes relevant when the aggregator settles bidirectional energy against a mobility contract.

Q8. CHAdeMO or ISO 15118-20 for a mixed fleet?

Specify both as configurable options in the RFQ. Order CHAdeMO BiDi for depots with Nissan Leaf or Japanese-market vehicles; order ISO 15118-20 for depots standardising on CCS2. The Numbat charger supports both in a single cabinet; the HG Power V2G Bidirectional Series offers CCS2 and CHAdeMO as configurable connector options.

Q9. How long does V2G interconnection approval take?

Typical timelines in 2026: UK G99 Type Tested 4–8 weeks, California Rule 21 6–12 weeks, Germany VDE-AR-N 4105 2–6 weeks for notifiable installations and 8–16 weeks for 4110 medium-voltage. Submit the application before placing the hardware order.

13. References

Block A — standards and regulation

• ISO 15118-20:2022, Road vehicles — Vehicle to grid communication interface — Part 20: 2nd-generation network layer and application layer requirements.
• IEC 63584:2024 (OCPP 2.0.1 as international standard).
• CHAdeMO Association, Bidirectional charging protocol specification.
• Engineering Recommendation G99, Issue 1 Amendment 10, 2024 (UK Energy Networks Association).
• CPUC Rule 21, UL 1741 SB, IEEE 1547-2018.
• VDE-AR-N 4105:2018-11 and VDE-AR-N 4110.
• Regulation (EU) 2023/1804 (AFIR).

Block B — pilots and economics

• Los Angeles Air Force Base V2G demonstration (DoD / CAISO).
• NYSERDA and Efficiency Maine school-bus V2G reports.
• Octopus Energy, Cenex, Nuvve, Fermata Energy, The Mobility House public case studies.
• Wallbox Quasar, Zaptec Pro V2G, Numbat and Watt&Well product documentation.

Reviewed by HG Power product engineering (V2G Bidirectional Series). Author: Marvin Zhou, Head of International Marketing, HG Power (Shenzhen Hongjiali New Energy Co., Ltd.). Last updated: 2026-10-30.