Per-kWh billing is an EV charging pricing method in which the driver is charged based on the energy delivered, measured in kilowatt-hours (kWh). It is the most direct “pay for what you use” model, similar to paying for electricity at home.
Why Per-kWh Billing Matters in EV Charging
Per-kWh billing is widely used because it is intuitive and generally perceived as fair. It helps operators and customers:
– Align cost with actual energy consumption (not parking duration)
– Improve price transparency and easier comparison across sites
– Reduce complaints from slow-charging vehicles compared to time-based tariffs
– Support fleet and corporate reporting (energy per vehicle, per route, per depot)
– Enable clearer revenue forecasting tied to delivered energy
How Per-kWh Billing Works
A typical per-kWh billing process includes:
– The charger (or an attached meter) measures energy delivered during the session
– The CPMS records meter values and applies the configured €/kWh tariff
– Optional additional fees may apply (session fee, parking fee, idle fees)
– The final invoice/receipt shows kWh delivered and the total cost
Metering and Compliance Considerations
Because per-kWh billing is based on measured energy, it often requires compliant metering depending on the market:
– MID metering (EU Measuring Instruments Directive) is commonly required or strongly preferred for accurate, legally defensible billing
– Some countries require specific national metrology approvals or sealing requirements
– Meter data integrity and auditability matter for dispute handling (timestamps, meter start/end values)
Benefits
– Fair and user-friendly: pay for energy delivered
– Better suited to variable charging speeds across EV models
– Strong basis for fleet energy accounting and CO₂ reporting
– Works well with smart charging (users can still pay for delivered kWh even if power is throttled)
Limitations and Practical Considerations
– Regulatory constraints: some regions restrict or tightly regulate kWh resale unless metering rules are met
– Needs reliable meter reading, calibration, and secure data transfer
– Per-kWh pricing alone may not prevent bay blocking; idle fee policies are often needed
– In very slow or congested sites, operators may prefer hybrid tariffs to manage turnover
Related Glossary Terms
kWh-Based Billing
MID Metering
Interval Metering
Charging Session Revenue
Idle Fee Policy
Idle Fees
Pay-as-you-go Charging
Payment Terminals
CPMS
Smart Charging