MID metering is the use of EU MID-compliant electricity meters to measure energy (kWh) for billing or other legally relevant purposes. In EV charging, MID metering is typically required or strongly preferred when customers are charged based on €/kWh, because it ensures the measured energy used for invoicing meets defined accuracy, conformity, and marking rules.
What Is MID Metering?
MID metering means the energy measurement comes from a meter that complies with the Measuring Instruments Directive (MID) and has passed a conformity assessment. In practice, MID metering involves:
– An approved electricity meter (often with accuracy class such as Class B or Class C)
– Proper MID markings and documentation
– Installation and sealing/tamper features where required
– Traceability between the meter, the charger, and the charging transaction
Why MID Metering Matters in EV Charging
MID metering supports fair and transparent charging by:
– Improving billing accuracy and reducing disputes
– Strengthening consumer trust in public and semi-public charging
– Meeting tender requirements and regulatory expectations
– Supporting auditable billing records for fleets, workplaces, and public charging
– Helping operators reconcile billing with energy procurement and revenue share models
For CPOs, MID metering is often a mandatory requirement in public procurements and commercial contracts.
Where MID Metering Is Implemented
Charger-integrated MID metering
– Meter is inside the EV charger and measures energy per connector/session
– Best suited for pay-per-use billing and detailed charging session reporting
External MID meters in meter cabinets
– Meter measures a feeder or group of chargers (site-level or zone-level)
– Useful for cost allocation, validation, or energy management
– Less granular for per-session billing unless combined with additional allocation logic
Many deployments use both: charger-level MID metering for transactions and a cabinet meter for site totals and cross-checking.
How MID Metering Supports Billing Workflows
– The charger or meter records kWh delivered during the session
– The CPMS retrieves the metering values and applies the tariff (€/kWh + any fees)
– Session receipts and invoices reference the billed energy
– Meter IDs and logs provide auditability for disputes or inspections
To be “billing-ready,” metering values must be consistent, time-stamped, and traceable to the specific charging point and session.
Key Requirements and Good Practices
– Ensure the meter has valid MID markings and documentation
– Keep seals intact where required and plan replacement procedures accordingly
– Confirm the CPMS uses the correct meter registers for billing
– Maintain asset mapping: charger serial → meter ID → connector ID → location
– Provide clear tariff display to users (€/kWh, session fee, idle fee, VAT)
– Ensure good maintenance access to the meter for inspection or replacement
– Use reliable data logging to protect against missing or duplicated session reads
Common Issues
– Billing disputes caused by non-certified or incorrectly configured metering
– Incorrect installation (CT polarity, wiring, wrong register mapping) creating large errors
– Using a feeder-level meter for per-session billing without a transparent allocation method
– Broken seals or missing documentation undermining legal-for-trade credibility
– Data gaps due to connectivity issues between charger, meter, and CPMS
Related Glossary Terms
MID
MID Class B / C
Energy meter
Meter cabinets
Charging session reporting
Tariff structure
CPO (Charge Point Operator)
CPMS
Fiscal metering
Merchant accounts