How much to charge at a charging station: setting the kWh price

The kWh price is the decision the charging station owner most puts off and most guesses at. It is usually born copied from the neighbor on opening day and stays the same for months. This article shows how to arrive at a price from your own math: the floor, below which every charge runs at a loss, the ceiling, above which the driver leaves, and the price for each time of day in between. The figures are those of your point. Here is the method.

If you are looking for how much it costs to charge as a driver, the right text is the kWh price at a charging station.

The price is free, and it is yours

Under ANEEL, any interested party may provide electric vehicle charging, including for commercial exploitation with freely negotiated prices. The rules are in Chapter V of Resolution No. 1,000/2021 (ANEEL's page on electric vehicles). There is no official table. What exists is the obligation to inform: the Consumer Protection Code guarantees the customer adequate and clear information about the service price (Law 8,078/1990, art. 6, III). The driver needs to see how much they will pay before starting the charge. Tax on the charge is a matter for the accountant, and the answers from the São Paulo and Paraná revenue departments on the ICMS of charging, along with what is still missing to support the ISS, are gathered on the Velquia blog: does a charging station pay ICMS or ISS?.

The floor: how much each kWh you sell costs

The floor is the sum of three costs, all per kWh.

1. The energy

It is the biggest cost and the one that varies most from one point to another, because it depends on how the property buys energy. ANEEL divides consumer units into two groups (tariff types):

• Group B, low voltage: the conventional type has a single rate all day. The white tariff, also available for commerce and services, has three values on business days (peak, intermediate and off-peak) and charges the off-peak value on weekends and national holidays.
• Group A, medium and high voltage: the green and blue time-based types charge consumption by tariff period and also charge for power demand. At a point with a fast charger, the demand weighs on the bill even in a low-use month.

To find the energy cost per kWh, divide the portion of the bill that belongs to the charger by the kWh it delivered in the month. If it shares the meter with the rest of the property, a separate meter makes this calculation exact. Distributed generation energy credits, provided for in Law 14,300/2022, are one way to lower this number. At our points we use solar generation energy credits, with a cost per kWh lower than the utility's rate.

2. The payment platform fee

Whoever unlocks the charge and collects from the driver usually keeps a share of each sale, as a percentage, as a fixed amount per session, or both. It comes out of the price the driver pays, which is why it enters the calculation differently, as you will see in the formula.

3. The month's fixed costs

Maintenance, the charger's internet connection, rent or use of the space, insurance and whatever else the point pays every month, whether it is used or not. Divide the total by the kWh sold in the month. This cost per kWh falls as the point sells more, which is why an idle point needs a higher price to break even.

The floor formula

With E for the energy cost per kWh, F for the month's fixed costs divided by the month's kWh, and T for the platform's percentage fee:

minimum price = (E + F) ÷ (1 − T)

If the platform also charges a fixed amount per session, divide that amount by the average kWh of a session and add it to F. Below the minimum price, every kWh sold runs at a loss. The margin is what you put above it. The complete calculation of the month's result is in how much a charging station earns.

The ceiling: what the driver compares

Someone who drives electric looks at the price in the app before leaving, and compares. The ceiling of your price comes from three comparisons:

• The charging stations around: price, power, connector and whether they are free or have a queue. A cheaper neighbor with the same power a few minutes away pulls in the driver who has no reason to stop at your location.
• The type of charge: DC fast charging delivers useful charge in the time of a break and is billed accordingly. AC slow charging competes with the home outlet. The difference between the two is in fast or slow charging.
• What the location offers: restroom, coffee, security, cover, operating hours. The wait is part of what the driver compares, and a comfortable location sustains a price that an isolated point cannot.

If the floor ends up above the ceiling, the problem is not the price. It is the cost, and the conversation turns to energy, fixed costs or the platform fee.

Between the floor and the ceiling: time-based pricing

A single price treats the rush hour and the empty small hours the same. Look at the session times over a month. If there are full hours and empty hours, two or three prices work better than one:

• In the full hours, a price near the ceiling. The driver is already coming.
• In the empty hours, a lower price, like an overnight rate, to draw in those who can choose when to charge: app drivers, people who live nearby, a fleet that runs during the day.
• If your electricity bill is time-based, check which band your utility's peak periods fall into. A low price right at peak sells the most expensive energy for the lowest amount.

The empty-hour price only works if it stays above the floor for that hour.

Other ways to bill

The kWh is the most transparent method for the driver, because they pay for the energy that entered the battery. There are others, which can come alongside it:

• Occupancy time after the charge: an amount per minute once the battery is full and the car stays in the space. It serves to free up the charger, not to earn revenue.
• Fixed amount per session: covers the fixed cost of each short charge.
• Plans for those who return: a reason for the local driver to choose your point every week.

Version 2.1 of OCPP, the protocol between the charger and the management system, provides for sessions with a fixed cost, by energy or by time (Open Charge Alliance). In practice, what you can bill depends on your payment platform: ask it before you announce anything. Whatever the rule, it needs to be clear to the driver before the session.

When to review the price

• The electricity bill changed in value or in type.
• A charging station opened or changed its price near yours.
• The empty hours stay empty even with the lower price.
• The payment platform fee changed.

Before lowering the price to attract people, check whether the problem is really the price. A charger that stops without you knowing, a point that is hard to find and a lack of support drive the driver away at any price. The six most common causes are in a charging station with little use.

Where Elektro Charge comes in

In Elektro Charge charging station management, the price comes from the data. The platform on which we run our network tracks occupancy by day and time, the charges and the peak times of the charging stations around yours, and the point study adjusts price and hours by the usage data of your charger, with time-based rates, like the overnight one, and plans and referrals to bring the driver back. The path to cheaper energy is part of the same study. The complete routine of running a point is in charging station management, and our points are in charging points.