Charging Business
How to Price EV Charging: per kWh, per Minute or per Session
Choosing a price model for EV charging: per kWh, per minute or per session, idle fees, time-of-day prices, memberships and price-display rules.
- Prepared by
- VULTAE Engineering Team
- Published
- Reading time
- 4 min
- Sources
- 3 references
Key takeaways
- 1Pricing per kWh is the fairest model — drivers pay for the energy they get — and in many markets it is the expected or required basis for public charging. It needs a billing-grade meter.
- 2Per-minute pricing rewards fast-charging cars and penalises slow ones; it is useful as an idle fee after charging ends, less so as the main price.
- 3Combine a per-kWh price with an idle fee and time-of-day prices to cover demand charges, keep bays free and move demand to quiet hours.
- 4Show the price before the session starts. In the EU, AFIR requires ad-hoc prices to be clear and, for public chargers of 50 kW and above, based mainly on the energy delivered.
Contents
Short answer: price public charging per kWh as the main component — it is fair, easy to compare, and in more and more markets the expected or required basis. Add an idle fee per minute after charging ends to keep bays free, use time-of-day prices if your electricity tariff varies, and offer memberships or fleet contracts for regular users. Show the price before the session starts, and make sure your meters are approved for billing where you sell by the kWh.
The main price models
| Model | How it works | For | Against |
|---|---|---|---|
| Per kWh | Driver pays for energy delivered | Fair; easy to compare; matches your energy cost | Needs a billing-grade meter; does not discourage long stays |
| Per minute | Driver pays for time connected | Encourages turnover; simple metering | Unfair to cars that charge slowly or in cold weather |
| Per session | Fixed fee per charge | Very simple | Unfair between small and large sessions; hard to cover costs |
| Subscription / membership | Monthly fee for lower prices | Loyal users, predictable revenue | Needs an account system |
| Flat fee for hosts | Hotel or employer includes charging in another price | Simple for guests or staff | No direct revenue from charging |
Most operators now combine them: per kWh + idle fee, with lower prices for members or fleets.
Setting the price per kWh
Work up from your costs:
| Cost per kWh component | How to estimate |
|---|---|
| Energy | Tariff per kWh, by time of day |
| Demand and fixed grid charges | Annual charges ÷ expected kWh sold |
| Payment, roaming, software | Fees per transaction or per kWh |
| Maintenance and site costs | Annual costs ÷ expected kWh |
| Capital recovery | Annual financing or depreciation ÷ expected kWh |
| Margin | Your target |
Because several components are fixed, the cost per kWh is much higher at low utilization — see the worked example in is an EV charging station profitable?. RMI’s DC fast-charging tariff study showed how demand charges can multiply the effective electricity cost at low use; a price that ignores them can lose money on every session in the early years.
Then check the market: competitors’ prices nearby, the cost of home charging, and the fuel cost of the same distance.
Idle fees
An idle fee starts after the battery stops charging — usually after a grace period of 10–15 minutes — and is charged per minute. It solves a real problem at busy sites: cars that stay plugged in while drivers shop or sleep. Make it visible on the charger, in the app and on the receipt.
Time-of-day pricing
| Period | Typical approach |
|---|---|
| Peak grid hours | Higher price, matching the utility’s peak tariff |
| Off-peak and night | Lower price to fill idle hours — useful for fleets and taxis |
| Weekend or holiday peaks on highways | Higher price or stricter idle fees to keep bays moving |
Time-of-day prices also help manage demand charges: lower demand at peak lowers the monthly peak. See demand charges.
Rules on price display and metering
| Market | What applies |
|---|---|
| EU | AFIR: ad-hoc prices must be clear, displayed before the session; for publicly accessible chargers of 50 kW and above, the ad-hoc price is based on the energy delivered, with possible time-based components for occupancy |
| Germany | Eichrecht: calibration-law-compliant metering and signed data for billing |
| Australia | EVSE used for trade made from 1 April 2026 must comply with NMI 14/4/0 |
| Other markets | Check national metrology and consumer-protection rules |
Charging per kWh without an approved meter can be illegal or unenforceable. Ask your supplier for the meter type and accuracy class — see MID meters and Eichrecht.
How the hardware supports pricing
| Function | Needed for |
|---|---|
| Energy meter, billing grade | Per-kWh pricing |
| OCPP 1.6J / 2.0.1 back end | Price changes, idle fees, memberships, reports |
| Card terminal or QR code | Ad-hoc payment without an account — see payment options |
| Screen showing the price | Transparency before and during the session |
| RFID | Members, fleets, staff |
VULTAE DC chargers have a Class 0.5 energy meter and support card terminals, QR code and RFID over OCPP 1.6J / 2.0.1; our dual-port AC chargers are available with MID-certified meters.
Questions buyers ask
- Should I charge per kWh or per minute?
- Per kWh in most cases: it is fair, transparent and increasingly required for public charging. Per-minute charges work best as an idle fee after the battery is full or as a time component at high-power sites where bays must turn over quickly.
- How do I set the price per kWh?
- Start from your full cost per kWh at the utilization you expect — energy, demand charges, fees, maintenance, software and capital recovery — then compare with local competitors and with the cost of fuel. Set different prices by time of day if your tariff does.
- What is an idle fee?
- A charge per minute that starts after charging ends, often after a grace period of 10–15 minutes. It keeps bays free for the next driver without penalising charging itself.
- Do I need a certified meter to charge per kWh?
- In many markets, yes: selling energy by the kWh is trade measurement. Europe uses MID-certified meters and, in Germany, Eichrecht; Australia requires NMI-approved EVSE for trade; other countries have similar rules. Check before you set a per-kWh price.
References
- [1]Regulation (EU) 2023/1804 on alternative fuels infrastructure (AFIR). EUR-Lex.
- [2]Trade measurement policy for electric vehicle supply equipment. National Measurement Institute (Australia).
- [3]DCFC rate design study. RMI.
