How much it costs to charge an electric car in Portugal

Why this question is so hard to answer

A petrol driver knows what a full tank costs. They know the price per litre, they know how many litres the tank takes, and the sum is a multiplication. Someone moving to an electric car expects to do the same with kWh and discovers, almost always after paying, that the sum does not add up.

It is not carelessness. At a Portuguese public post the price is not one number, it is several, and they come from different companies. The national network is run by MOBI.E and is interoperable, which means you can charge at posts belonging to any operator while holding a contract with a single supplier. That is a genuine advantage, and MOBI.E stresses it: you get one itemised invoice whichever post you use. The trade-off is that the invoice has to accommodate two companies, and so it carries two parcels¹.

The three things that make up the invoice

MOBI.E describes the invoice the supplier issues as the sum of three parcels¹.

The first is the energy parcel. It is the tariff of the electricity supplier for e-mobility, the CEME, the company you hold a contract with. Inside it are already the grid access tariffs and the special tax on electricity consumption, which MOBI.E puts at €0.001 per kWh on the mainland under Portaria 320-D/2011. That is why it makes no sense to add those on top: they are already inside the per-kWh price on display.

The second is the post usage parcel. It corresponds to the tariff of the charging point operators, the OPCs, for the service of making the post available. The operator owns the equipment and is a separate company from the supplier. This parcel is billed on the supplier's invoice and then transferred to the operator.

The third is taxes, and on this MOBI.E leaves no room for interpretation: VAT, currently 23% on the mainland, 22% in Madeira and 16% in the Azores, «is applied to the whole invoice»¹. The mainland rate is the standard rate of article 18(1)(c) of the Portuguese VAT Code, and the lower rates in the autonomous regions exist because article 18(3) allows the Legislative Assemblies of the Azores and Madeira to set reduced VAT rates³.

The finding: the same kWh is charged twice, under two names

This is the part that solves the mystery, and MOBI.E writes it itself, in its FAQ, about the components an operator may combine²:

Note that the cost per unit of energy component corresponds to a service (use of the point) and not to the supply of electricity, which is always the responsibility of the suppliers.

Read it slowly. The post operator may also charge in euros per kWh. But what it is selling in that unit is not electricity, it is the right to use the equipment. That is why the two figures add up instead of one replacing the other.

The driver sees €0.22/kWh on display, multiplies by the 36 kWh they need, arrives at €7.92 and drives off content. The invoice then adds the operator's per-kWh component, the per-minute component, any activation fee, and charges VAT on all of it. There is nothing irregular about this: it is how the price is built, and it is published. It is simply not published anywhere you would read it before charging.

The three components of the operator tariff

MOBI.E lists them and says the operator may «combine one, two or three of these components»².

It adds that operator tariffs may «vary through the day, or differ within the same post depending on the power of the charging points», and that operators are free to set the tariffs they see fit. There is therefore no national price for charging, and any article that gives you one is giving you an average that is not yours.

The per-minute component makes your car a cost factor

This is the component that produces the biggest surprises, because it does not depend on what you take but on how long you take to take it.

Every model has its own limit on the power it accepts, in alternating and in direct current, and that limit belongs to the car, not to the post. A car limited to 7.4 kW plugged into a 22 kW post does not charge at 22 kW: it charges at 7.4 kW, and occupies the post about three times as long to take exactly the same energy. If the operator charges per minute, that driver pays roughly three times that component compared with the driver next to them, for the same electricity.

Two practical consequences follow. The first is that it is worth knowing the power your car accepts before choosing an expensive post for being fast. The second is that, where there is a per-minute component, leaving the car plugged in after it has finished costs money and delivers no energy.

There is also a technical detail pulling the same way: above roughly 80% state of charge the power drops considerably, because the battery limits it. A session to 100% takes far longer than the proportion suggests, and with a per-minute component the last 20% can cost almost as much as the first 60%. That is why, on a journey, charging from 20% to 80% is nearly always the cheaper call.

The sum, with numbers

Take a car with a 60 kWh battery, charged from 20% to 80%. That is 36 kWh, not 60, because you only pay for the slice that goes in. At a 50 kW rapid post it takes about 43 minutes. Suppose the post shows energy at €0.22/kWh, an operator tariff of €0.30/kWh plus €0.08 per minute, and no activation fee.

Divided by the 36 kWh, that is €0.758 per kWh, which is 3.44 times the energy price that was on display. The same charge at home, at €0.18/kWh including VAT, would cost €6.48: a difference of €20.80 in a single session.

Converted to distance, at a consumption of 17 kWh/100 km, that is €12.88 per 100 km at the post against €3.06 per 100 km at home. Hold on to the order of magnitude, because it drives the decision: €12.88 per 100 km is more than a petrol car doing 6 litres per 100 km at €1.80 a litre, which would spend €10.80.

The conclusion is not that electric cars are expensive. It is that almost all of the saving from an electric car sits in where you charge it. A driver who charges at home pays roughly a third of the equivalent fuel; a driver who depends exclusively on rapid posts can pay more than they did before.

At home the sum is different

At home there is no post operator, no per-minute component and no activation fee. There is your electricity contract and the per-kWh price you already pay for everything else, so the sum is a multiplication.

Two honest caveats. The first is that the meter counts the energy leaving the wall and the battery keeps less than that: there are charging losses, especially on alternating current, so the real cost per usable kWh is slightly above what any simple sum suggests. The second is that domestic electricity in Portugal carries a reduced VAT rate on part of the monthly consumption for low contracted power, but that part is allocated to the household's total consumption rather than to the car, so it is not derivable from the inputs of a single charge. We would rather explain it than approximate it.

Networks not connected to MOBI.E

Everything above describes the MOBI.E network. MOBI.E itself separately describes the model used by networks that are not connected to it, which differs¹: there may be a periodic subscription fee, paid in advance, giving access to better conditions; energy and post usage appear bundled into a single parcel, which may be billed in kWh, in minutes, per session or in a mix; and a fee from the e-mobility service provider is added. If you charge on such a network, the logic of adding the parcels still holds, but the names and the number of lines change.

What to do with this

Before charging, read two things off the post or the app: the operator tariff, including whether it has a per-minute component or an activation fee, and your supplier's energy price. MOBI.E offers a post-by-post lookup on its Find a Post page, and reminds users that the tariff for this parcel is always displayed at the post².

Then run the sum with your own numbers in the EV charging cost calculator, which returns the total, the effective price per kWh and the cost per 100 km. To close the comparison with the car you had before, the other side is done in the fuel cost calculator.