The EV charging cost per kWh is the number every fleet manager compares. The charger screen shows one, in euros per kilowatt-hour, and the question looks answered. It is not. That tariff covers a single component of the bill. Occupation fees billed by the minute once the vehicle stays plugged in, occasional per-session fees, and operator-specific tariffs stack on top. Measured on our clients' actual charging sessions, the cost per kWh ranges from €0.46 to €1.30 on slow charging alone, depending on how long the vehicle stays plugged in. A fleet that picks its chargers by the displayed tariff is flying blind.
- Slow charging (AC ≤ 22 kW) averages €0.73 per kWh ex-VAT, against €0.51 on ultra-rapid. Time spent plugged in weighs more than charger power.
- A slow session left plugged in for more than 12 hours costs €1.30 per kWh. These sessions are 16% of slow charging and 43% of the corresponding spend.
- The European AFIR regulation requires every price component to be displayed before the session starts. Thirty seconds of reading changes the bill.
What a public charging session actually bills
On a public charger, the bill combines three components. Energy, billed per kilowatt-hour, is the only figure most drivers compare. Time comes next. Once the battery is full or a duration cap is exceeded, many operators bill occupation fees by the minute. The session completes the picture: some networks add a fixed amount per charge, which weighs all the more heavily on small sessions.
This model is not illegal, it is regulated. Regulation (EU) 2023/1804, known as AFIR, requires prices that are transparent and easily comparable, and it explicitly allows occupation fees charged per minute to discourage lengthy occupation of the charging point[1]. On chargers of 50 kW and above, the price without a subscription must be based on the price per kWh. Below 50 kW, the operator must disclose every component in an imposed order: price per kWh, price per minute, price per session[2]. And that price list must be visible on the charger before the session starts[3].
Transparency exists, on paper and on screen. Someone still has to read it. A driver in a hurry who plugs in without checking the full price list pays for all three components, including the one they never saw.
What 15,168 fleet charging sessions say
To measure the real effect of these components, we analysed our own transactions: 15,168 charging sessions carried out in France by client fleets over 12 months, ex-VAT amounts paid to operators, parking fees included. Three power families emerge, and their weights do not line up. Slow charging (AC ≤ 22 kW) accounts for 38% of sessions but only 30% of energy and 38% of spend. Ultra-rapid (≥ 150 kW) concentrates 51% of sessions and 59% of energy, yet 53% of spend. In other words, slow charging moves little energy and costs proportionally dear.
| Charging type | Share of sessions | Share of energy | Share of spend | Avg ex-VAT kWh |
|---|---|---|---|---|
| Slow, AC ≤ 22 kW | 38% | 30% | 38% | €0.73 |
| Rapid, DC < 150 kW | 11% | 11% | 9% | €0.46 |
| Ultra-rapid, ≥ 150 kW | 51% | 59% | 53% | €0.51 |
The median sessions tell the same story. The typical slow session transfers 18 kWh over 3 hours 6 minutes plugged in. The rapid one moves 25 kWh in 42 minutes, the ultra-rapid 31 kWh in 31 minutes. A session costs €15.41 ex-VAT on average across all power levels. And the most expensive kWh in the sample is not where you expect it: it hides in slow charging, when the charger becomes a parking spot.
Why slow charging costs more per kWh
The mechanism fits in one sentence: time-based fees keep accruing while the battery has long been full. A median slow session lasts 3 hours 6 minutes for 18 kWh. Past that point, every extra hour adds almost no energy but keeps generating per-minute occupation fees. The denominator stalls, the numerator climbs.
The data is blunt about it. Below one hour plugged in, the slow kWh costs €0.46. Between 1 and 4 hours, €0.56. Between 4 and 12 hours, €0.55. Beyond 12 hours, it climbs to €1.30, nearly three times the first bar. These marathon sessions are not rare: 16% of slow sessions exceed 12 hours plugged in and carry 43% of slow-charging spend. A minority of sessions absorbs close to half the budget.
The time-of-day profile makes it worse: 24% of sessions start between 6 pm and 6 am. Plugging in on a public charger in the evening and picking the vehicle up in the morning means using charging infrastructure as a parking space. Operators, whose charger sits immobilised, bill exactly that behaviour. The kWh itself never changed price.
Five levers to take the bill back in hand
An unplug rule. Set a maximum plug-in time and enforce it, starting with evening sessions. The spend concentrates on 16% of slow sessions: you recover it by moving hours around, not by renegotiating the per-kWh tariff.
End-of-charge alerts. The driver can know from their phone that the battery is full, and most vehicles already signal it. What is missing is the organisational reflex: who gets notified, who unplugs, within what deadline. An alert with no instruction behind it stays a gadget.
Charger selection. At equal power, two neighbouring chargers can lead to very different bills once every component is added up. Our interactive map lets you compare charger tariffs before the trip, so the decision no longer rests on the per-kWh price alone.
A home-charging policy. Vehicles that sit outside all night have no business on a public charger in the evening. Moving those sessions to drivers' homes or to the site, where possible, takes volume away from the slot that is most profitable for operators, and therefore most expensive for you.
Reading the tariffs before plugging in. AFIR makes the full price list visible on the charger before the session[3]. Thirty seconds are enough to spot a high per-minute price or a session fee that penalises small charges. To arbitrate the power level itself, our criteria for choosing a charger summarise what matters, and the fuel and charging card consolidates both expense flows into one supporting document.
On slow charging, the kWh climbs from €0.46 to €1.30 with time plugged in. 16% of sessions exceed 12 hours and concentrate 43% of the spend. A fleet's first lever is not the per-kWh tariff: it is the unplug time.
Frequently asked questions
What do fleets actually pay per kWh at public chargers?
On our data (15,168 fleet charging sessions in France over 12 months, ex-VAT amounts, parking fees included), the kWh averages €0.73 on slow charging, €0.46 on rapid and €0.51 on ultra-rapid. The typical session bills €15.41 ex-VAT. The figure on the screen predicts none of these averages on its own.
What are occupation fees on an EV charger?
An amount billed per minute of plug-in time, beyond a threshold set by the operator, to discourage immobilising the charger. The AFIR regulation explicitly allows them in this form[1]. They are the most likely explanation for the gap between a €0.46 kWh and a €1.30 kWh on slow charging: for comparable energy, only the plug-in time changes.
Why does slow charging cost more per kWh than ultra-rapid?
Because the bill mixes energy and time. On ultra-rapid, the vehicle stays plugged in for a median 31 minutes: time-based fees weigh little. On slow charging, it stays for a median 3 hours 6 minutes, and sometimes over 12 hours. The charger then mostly bills occupation.
Does the price shown on the charger include all fees?
In theory, yes. AFIR requires the per-kWh price and the per-minute occupation fees to be displayed on the charger before the session starts, and every price component for points below 50 kW[2][3]. In practice, the components read line by line: their sum, not the first figure, predicts the bill.
Umbrella article: this piece complements our comparison of business EV chargers, which covers purchase prices, the manufacturer landscape and selection criteria.
References
- Regulation (EU) 2023/1804 of 12 September 2023 (AFIR), Article 5(3) and (4): prices must be transparent and easily comparable; operators may bill occupation fees per minute to discourage lengthy occupation of the charging point. eur-lex.europa.eu. ↩
- Regulation (EU) 2023/1804 (AFIR), Article 5(4): for charging points below 50 kW, the ad-hoc price must be disclosed with all its components, in the order price per kWh, price per minute, price per session. eur-lex.europa.eu. ↩
- Regulation (EU) 2023/1804 (AFIR), Article 5(4): the ad-hoc price per kWh and the per-minute occupation fees must be displayed on the charging point before the session starts, mandatory for points deployed since 13 April 2024. eur-lex.europa.eu. ↩
