Feasibility of an Ecotricity supplier-led e-MSP that unifies home and public EV charging Ecotricity no longer operates the Electric Highway, but as a licensed electricity supplier with established green energy provenance, it seems uniquely positioned to act as an e-MSP and provide a single contract that covers both domestic (home) charging and roaming public charging. I am interested in technical, regulatory, and commercial feasibility of such a model in the UK, and what it would take to implement it at scale. Key questions and design considerations: Architecture and protocols Would an e-MSP operated by a supplier rely on OCPI 2.2.1 token provisioning to interoperate with CPOs while maintaining a unified customer ledger? Any blockers to mass token sync across major UK CPOs? What are practical differences if OCPP 2.0.1 with ISO 15118 Plug&Charge is used versus app/RFID, specifically for certificate issuance, revocation, and liability allocation between supplier-e-MSP and CPO? How would back-office settlement handle near-real-time price signals if the e-MSP offers dynamic tariffs linked to wholesale half-hourly prices? Billing, VAT, and receipts Can one invoice legally itemize domestic kWh at 5% VAT and public kWh at 20% VAT while preserving HMRC-compliant receipts per session (time, location, MID meter kWh, unit price)? How would MID meter readings from CPOs be reconciled with customer-level postpaid billing without losing per-session auditability required for business expense claims? Carbon accounting and REGOs If Ecotricity allocates REGOs to public charging, how can double counting be avoided when CPOs also claim “100% renewable”? Is there a clear path to GHG Protocol-compliant market-based claims for end users? Would a granular certificate scheme (hourly/half-hourly) be necessary to credibly match dynamic pricing with carbon intensity at the charger? Practical sources and registries? Settlement and network charges Could BSC mechanisms (e.g., HH settlement, P415-style flexibility trading) or DNO flexibility products be leveraged to reduce DUoS/BSUoS at specific sites and pass through savings to end users? Any regulatory barriers in Ofgem licensing to a supplier operating as an e-MSP and offering postpaid credit for public charging at scale? Identity, privacy, and customer experience Is there a defensible way to use MPAN-linked identity for seamless authentication across home and public contexts without exposing personal data to CPOs (GDPR, data minimization)? For fleets and salary-sacrifice users, can cost splitting (home vs public) be automated with distinct VAT treatments and configurable cost-center tagging per session? Risk management and resiliency How should preauthorization and credit risk be handled during roaming to avoid high collateral holds while guaranteeing CPO revenue? What happens under CPO outage or roaming hub failures? Recommended SLAs and fallbacks (offline authorization lists, pricing at loss-of-comms, dispute resolution windows)? Hardware implications For home charging, what capabilities are required on the EVSE (OCPP client, smart meter integration via HAN, load management) to integrate tariff signals and keep a unified usage ledger? Is there any material advantage to implementing ISO 15118 PnC now for UK public roaming given current certificate authority maturity and OEM readiness? I would be interested in experiences from CPOs, suppliers, and e-MSPs who have attempted anything similar (even outside the UK), as well as insight on: The most brittle points in OCPI-based roaming when adding dynamic pricing and near-real-time carbon signals. Typical discrepancies between CPO-reported kWh and e-MSP billed kWh and how they are resolved at scale. The minimum viable product that could be piloted with a subset of CPOs and early adopters without running afoul of VAT and receipt rules. If this model is feasible, it could materially improve user experience and carbon transparency while reducing friction for fleets. Where are the hard blockers today, and which ones are realistically solvable within the current regulatory period?

Feasible, but only if you’re ruthless about scope. The fantasy is “unified everything”; the reality is a bunch of seams you can’t paper over with OCPI alone. Settlement/network charges: You can’t arbitrage DUoS/BSUoS on roaming sessions unless you also supply the site MPAN. BSC P415 and DNO flex are for behind-the-meter loads with your metering/consent; they don’t magically reduce costs on a third party’s supply. Treat any “flex savings pass-through” claims on roaming with suspicion. OCPI at scale: Token sync is fine but brittle around caching and mid-session tariff changes. Lock pricing at session start, publish validity windows, and agree dispute tolerances. The ugly bits: timezone drift, tariff component rounding, and CDR rewrites after firmware updates. VAT/receipts: A single invoice with mixed VAT rates is fine if you subtotal 5% vs 20% and keep per-session lines available for download. For audit, settle on the CPO’s CDR (MID meter) as source of truth and reconcile monthly; expect 0.5-2% kWh deltas from rounding/clock drift. Anything higher means a firmware or tariff mapping issue. Carbon/REGOs: You can’t credibly claim “100% renewable to the driver” on roaming unless you either supply the charger or contractually acquire the environmental attribute for those kWh (and the CPO stops claiming it). UK REGOs are annual; hourly matching isn’t production-grade yet-EnergyTag pilots exist, but don’t tie dynamic price to carbon in your marketing beyond “informational”. Identity/privacy: Do not leak MPANs. Use pseudonymous contract tokens; map to MPAN internally. For fleets/salary sacrifice, issue distinct tokens per cost centre with separate VAT treatment and caps. Payments/credit: If you’re the e-MSP merchant of record, you’ll need a payments model that fits PSD2 (most use the commercial agent exemption) and to avoid tripping Consumer Credit rules (keep to normal monthly billing terms). Reduce risk with small rolling preauths, spend limits, and roaming via a hub that gives you settlement guarantees/bank guarantees. Resilience: Demand offline auth lists for RFID, a price-at-loss-of-comms fallback, and 60-90 day dispute windows. Measure CPO uptime and OCPI endpoint SLAs separately; roaming hubs go down more than anyone admits. Home hardware: If you want reimbursable kWh, insist on MID-grade metrology and OCPP 1.6J; don’t depend on SMETS2 HAN/DCC access. Use supplier price APIs and PAS 1878/1879-style schedules. Load management is a must for multi-asset homes. Plug & Charge: Still not worth betting the farm on in the UK-certificate issuers/liability splits aren’t widely bedded in, and CPO support is patchy. Keep RFID/app first; add 15118 later. Minimum viable pilot: 2-3 CPOs via Hubject/Gireve, tariff-at-start pricing, monthly mixed-VAT invoice with downloadable session receipts, REGO retirement against public kWh where you have the attribute rights, one approved home charger SKU with MID meter. Don’t promise network charge savings; your biggest risks are data quality, REGOs double-claiming, and payments compliance-all solvable with tight contracts and a very narrow tech stack.

Ecotricity Ev Charging

ChargedLife

Feasibility of an Ecotricity supplier-led e-MSP that unifies home and public EV charging

Ecotricity no longer operates the Electric Highway, but as a licensed electricity supplier with established green energy provenance, it seems uniquely positioned to act as an e-MSP and provide a single contract that covers both domestic (home) charging and roaming public charging. I am interested in technical, regulatory, and commercial feasibility of such a model in the UK, and what it would take to implement it at scale.

Key questions and design considerations:

Architecture and protocols
- Would an e-MSP operated by a supplier rely on OCPI 2.2.1 token provisioning to interoperate with CPOs while maintaining a unified customer ledger? Any blockers to mass token sync across major UK CPOs?
- What are practical differences if OCPP 2.0.1 with ISO 15118 Plug&Charge is used versus app/RFID, specifically for certificate issuance, revocation, and liability allocation between supplier-e-MSP and CPO?
- How would back-office settlement handle near-real-time price signals if the e-MSP offers dynamic tariffs linked to wholesale half-hourly prices?
Billing, VAT, and receipts
- Can one invoice legally itemize domestic kWh at 5% VAT and public kWh at 20% VAT while preserving HMRC-compliant receipts per session (time, location, MID meter kWh, unit price)?
- How would MID meter readings from CPOs be reconciled with customer-level postpaid billing without losing per-session auditability required for business expense claims?
Carbon accounting and REGOs
- If Ecotricity allocates REGOs to public charging, how can double counting be avoided when CPOs also claim “100% renewable”? Is there a clear path to GHG Protocol-compliant market-based claims for end users?
- Would a granular certificate scheme (hourly/half-hourly) be necessary to credibly match dynamic pricing with carbon intensity at the charger? Practical sources and registries?
Settlement and network charges
- Could BSC mechanisms (e.g., HH settlement, P415-style flexibility trading) or DNO flexibility products be leveraged to reduce DUoS/BSUoS at specific sites and pass through savings to end users?
- Any regulatory barriers in Ofgem licensing to a supplier operating as an e-MSP and offering postpaid credit for public charging at scale?
Identity, privacy, and customer experience
- Is there a defensible way to use MPAN-linked identity for seamless authentication across home and public contexts without exposing personal data to CPOs (GDPR, data minimization)?
- For fleets and salary-sacrifice users, can cost splitting (home vs public) be automated with distinct VAT treatments and configurable cost-center tagging per session?
Risk management and resiliency
- How should preauthorization and credit risk be handled during roaming to avoid high collateral holds while guaranteeing CPO revenue?
- What happens under CPO outage or roaming hub failures? Recommended SLAs and fallbacks (offline authorization lists, pricing at loss-of-comms, dispute resolution windows)?
Hardware implications
- For home charging, what capabilities are required on the EVSE (OCPP client, smart meter integration via HAN, load management) to integrate tariff signals and keep a unified usage ledger?
- Is there any material advantage to implementing ISO 15118 PnC now for UK public roaming given current certificate authority maturity and OEM readiness?

I would be interested in experiences from CPOs, suppliers, and e-MSPs who have attempted anything similar (even outside the UK), as well as insight on:

The most brittle points in OCPI-based roaming when adding dynamic pricing and near-real-time carbon signals.
Typical discrepancies between CPO-reported kWh and e-MSP billed kWh and how they are resolved at scale.
The minimum viable product that could be piloted with a subset of CPOs and early adopters without running afoul of VAT and receipt rules.

If this model is feasible, it could materially improve user experience and carbon transparency while reducing friction for fleets. Where are the hard blockers today, and which ones are realistically solvable within the current regulatory period?

greentechie

Feasible, but only if you’re ruthless about scope. The fantasy is “unified everything”; the reality is a bunch of seams you can’t paper over with OCPI alone.

Settlement/network charges: You can’t arbitrage DUoS/BSUoS on roaming sessions unless you also supply the site MPAN. BSC P415 and DNO flex are for behind-the-meter loads with your metering/consent; they don’t magically reduce costs on a third party’s supply. Treat any “flex savings pass-through” claims on roaming with suspicion.
OCPI at scale: Token sync is fine but brittle around caching and mid-session tariff changes. Lock pricing at session start, publish validity windows, and agree dispute tolerances. The ugly bits: timezone drift, tariff component rounding, and CDR rewrites after firmware updates.
VAT/receipts: A single invoice with mixed VAT rates is fine if you subtotal 5% vs 20% and keep per-session lines available for download. For audit, settle on the CPO’s CDR (MID meter) as source of truth and reconcile monthly; expect 0.5-2% kWh deltas from rounding/clock drift. Anything higher means a firmware or tariff mapping issue.
Carbon/REGOs: You can’t credibly claim “100% renewable to the driver” on roaming unless you either supply the charger or contractually acquire the environmental attribute for those kWh (and the CPO stops claiming it). UK REGOs are annual; hourly matching isn’t production-grade yet-EnergyTag pilots exist, but don’t tie dynamic price to carbon in your marketing beyond “informational”.
Identity/privacy: Do not leak MPANs. Use pseudonymous contract tokens; map to MPAN internally. For fleets/salary sacrifice, issue distinct tokens per cost centre with separate VAT treatment and caps.
Payments/credit: If you’re the e-MSP merchant of record, you’ll need a payments model that fits PSD2 (most use the commercial agent exemption) and to avoid tripping Consumer Credit rules (keep to normal monthly billing terms). Reduce risk with small rolling preauths, spend limits, and roaming via a hub that gives you settlement guarantees/bank guarantees.
Resilience: Demand offline auth lists for RFID, a price-at-loss-of-comms fallback, and 60-90 day dispute windows. Measure CPO uptime and OCPI endpoint SLAs separately; roaming hubs go down more than anyone admits.
Home hardware: If you want reimbursable kWh, insist on MID-grade metrology and OCPP 1.6J; don’t depend on SMETS2 HAN/DCC access. Use supplier price APIs and PAS 1878/1879-style schedules. Load management is a must for multi-asset homes.
Plug & Charge: Still not worth betting the farm on in the UK-certificate issuers/liability splits aren’t widely bedded in, and CPO support is patchy. Keep RFID/app first; add 15118 later.

Minimum viable pilot: 2-3 CPOs via Hubject/Gireve, tariff-at-start pricing, monthly mixed-VAT invoice with downloadable session receipts, REGO retirement against public kWh where you have the attribute rights, one approved home charger SKU with MID meter. Don’t promise network charge savings; your biggest risks are data quality, REGOs double-claiming, and payments compliance-all solvable with tight contracts and a very narrow tech stack.