The Cost of Charging an EV at Night in Portugal: Bi-horária vs Flat Rate
Published: 26/09/2026
The cost of charging an EV at night in Portugal: the short answer
Around €11 a month if you drive 1,000 km. That's the gap, using ERSE's regulated 2026 prices and 23% VAT, between charging at home on a flat-rate tariff and charging during the off-peak (vazio) hours of a two-period tariff. Over a year it adds up to roughly €134, and more than €200 if you cover 1,500 km a month.
The real cost of charging an EV at night in Portugal comes with some fine print, though. A two-period tariff makes daytime electricity more expensive for the rest of the house, the reduced 6% VAT rate rarely reaches your car's kWh, and a more powerful wallbox may force you to raise your contracted power. We ran the numbers for Portugal's best-selling EVs and all three tariff types, with everything that actually ends up on the bill.
Simples, bi-horária or tri-horária: the 2026 prices
Portuguese electricity contracts come in three flavours: simples (one flat price all day), bi-horária (two periods: vazio, off-peak, and fora de vazio, everything else) and tri-horária (three periods: vazio, cheias or mid-peak, and ponta or peak). The reference prices below are ERSE's regulated tariff for mainland Portugal, low-voltage contracts up to 20.7 kVA, in force since 1 January 2026. ERSE is the national energy regulator, and it publishes prices without VAT.
| Tariff option | Period | €/kWh (excl. VAT) | €/kWh (incl. 23% VAT) |
|---|---|---|---|
| Simples | All day | 0.1654 | 0.2034 |
| Bi-horária | Vazio (off-peak) | 0.1087 | 0.1337 |
| Bi-horária | Fora de vazio | 0.1988 | 0.2445 |
| Tri-horária | Vazio (off-peak) | 0.1087 | 0.1337 |
| Tri-horária | Cheias (mid-peak) | 0.1690 | 0.2079 |
| Tri-horária | Ponta (peak) | 0.2495 | 0.3069 |
An off-peak kWh is about 34% cheaper than a flat-rate kWh and about 45% cheaper than a fora de vazio one. Here's a detail many people miss: on the regulated tariff, the daily contracted-power charge is identical across all three options. At 6.9 kVA it's €0.3659 a day whether you pick simples or bi-horária. Switching carries no penalty on the fixed part of the bill.
Why off-peak is cheaper with every supplier
Most of the night discount doesn't come from the energy itself. It comes from the grid. The network access tariff (TAR), which ERSE sets and every supplier passes through on the bill, is €0.0158/kWh off-peak, versus €0.0835/kWh in fora de vazio and €0.0607/kWh on the flat rate. Of the 9 cents separating off-peak from the rest of the day, almost 7 cents come from this component alone.
In practice, that means free-market two-period offers also have cheaper nights, whichever brand is on your bill. The exact figures vary; the logic doesn't.
What changes on 1 October 2026
ERSE has approved a €0.005/kWh increase in the energy component of the regulated tariff from 1 October (Directive 4/2026), roughly 2.7% on the average bill. With VAT, that's about 0.6 cents more per kWh.
The increase is the same in every period. So the gap between off-peak and flat rate, and therefore your saving, stays practically unchanged. Someone charging for 1,000 km a month pays roughly €1 more on either option. The rise applies directly to around 779,000 regulated-market customers. Free-market suppliers aren't obliged to follow, though they usually do.
Home EV charging cost per 100 km for Portugal's best-sellers
For the per-model figures we used EV Database's real-world consumption estimates and the regulated prices for January to September 2026, including 23% VAT. The cars are Portugal's ten best-selling EVs from January to July 2026, according to ACAP, the Portuguese car industry association. The Peugeot E-2008 is missing because we couldn't get a comparable consumption figure for it.
| Model (sales rank) | kWh/100 km | Simples | Bi-horária, off-peak | Bi-horária, fora de vazio | Off-peak saving vs simples |
|---|---|---|---|---|---|
| Tesla Model 3 RWD (1st) | 13.3 | €2.71 | €1.78 | €3.25 | €0.93 |
| Tesla Model Y RWD (2nd) | 15.9 | €3.23 | €2.13 | €3.89 | €1.11 |
| Volvo EX30 (3rd) | 17.8 | €3.62 | €2.38 | €4.35 | €1.24 |
| Citroën ë-C3 (4th) | 17.2 | €3.50 | €2.30 | €4.21 | €1.20 |
| Mercedes CLA 250+ (5th) | 14.5 | €2.95 | €1.94 | €3.55 | €1.01 |
| BMW iX1 eDrive20 (6th) | 16.3 | €3.32 | €2.18 | €3.99 | €1.14 |
| Renault 5 52 kWh (7th) | 15.5 | €3.15 | €2.07 | €3.79 | €1.08 |
| Xpeng G6 RWD (9th) | 17.4 | €3.54 | €2.33 | €4.25 | €1.21 |
| BMW iX2 eDrive20 (10th) | 16.1 | €3.28 | €2.15 | €3.94 | €1.12 |
At €1.78 per 100 km when charged off-peak, the Tesla Model 3 is the cheapest car on the list to run. At the other end, the Volvo EX30 gains the most from night charging, saving €1.24 every 100 km. Away from home the maths changes: public charging prices in Portugal usually sit well above home off-peak rates.
Look closely at the fora de vazio column. If you switch to bi-horária and plug in the moment you get home at 7 pm, you'll pay more than you would on the flat rate. The discount only exists if charging is scheduled to start after 10 pm.
Charging for 500, 1,000 or 1,500 km a month
At an average 16 kWh/100 km, close to the Model Y, iX1 and iX2, the monthly numbers look like this (regulated 2026 prices, 23% VAT):
| km per month | kWh | Simples | Off-peak | Fora de vazio | Off-peak saving vs simples (month / year) |
|---|---|---|---|---|---|
| 500 | 80 | €16.28 | €10.70 | €19.56 | €5.58 / about €67 |
| 1,000 | 160 | €32.55 | €21.39 | €39.12 | €11.16 / about €134 |
| 1,500 | 240 | €48.83 | €32.09 | €58.69 | €16.74 / about €201 |
These figures leave out AC charging losses, which run at around 10%. Factor them in and 1,000 km a month costs about €35.81 on the flat rate and €23.53 off-peak. The annual saving then gets close to €150.
Simples vs bi-horária for an EV: the 37% rule
Your car doesn't live alone on the bill. Bi-horária makes daytime power pricier (€0.1988 versus €0.1654/kWh excl. VAT), and that hits the fridge, the oven and your working-from-home hours. At regulated 2026 prices, a two-period tariff only pays off when at least 37% of the household's total consumption falls in the off-peak window. Some comparison sites err on the side of caution and say over 40%.
An EV charged overnight pushes almost any household past that line. Take an illustrative example, excluding VAT: a home using 250 kWh a month, with a quarter of it at night, pays about €2.70 more on bi-horária than on simples. Add 160 kWh of off-peak charging (1,000 km) and the maths flips. The two-period tariff now comes out about €6.35 a month cheaper, or €7–8 with VAT, and more than half of the home's electricity is used off-peak.
That's less than the €11 in the previous table, because part of the car's saving covers the pricier daytime. It's still real money. The more you drive, and the more you shift the dishwasher or the electric water heater to the night, the wider the margin gets.
Since 1 January 2026, you can change tariff option or cycle at any time, with no 12-month lock-in. If the numbers don't work out, you can switch back at no cost.
Is tri-horária worth it for an EV?
For most homes up to 20.7 kVA, no. The off-peak price is the same as on bi-horária (€0.1087/kWh), but tri-horária adds a peak period at €0.2495/kWh that falls right when families are home in the evening. It mainly makes sense for high-power installations above 20.7 kVA.
Off-peak electricity hours in Portugal for EV charging
Bi-horária comes with two cycles, and choosing the right one matters as much as the tariff itself.
- Daily cycle (ciclo diário): off-peak from 10 pm to 8 am, every day of the year. That's 10 hours in a row, which covers almost any routine.
- Weekly cycle (ciclo semanal): on weekdays, off-peak shrinks to midnight–7 am. Saturdays have several windows (in winter, midnight–9:30 am, 1–6:30 pm and 10 pm–midnight; in summer, midnight–9 am, 2–8 pm and 10 pm–midnight), and Sunday is off-peak all day.
If you top up a little every night, the daily cycle is the easiest to live with. The weekly cycle can suit someone who mostly commutes and does one big charge at the weekend, provided the rest of the household's consumption adapts too.
Ten off-peak hours leave plenty of headroom. A 3.7 kW wallbox delivers around 37 kWh in one night, enough for more than 200 km at 16 kWh/100 km. If you drive 50 km a day, you need about 8 kWh, which is just over two hours of charging.
Portugal's off-peak hours change in 2027: reprogram your charger
On 31 July 2026, ERSE approved new time periods. On the daily bi-horária cycle, off-peak becomes 10:30 pm to 8:30 am. On the weekly cycle, weekday off-peak moves to 12:30–7:30 am. The winter/summer split disappears, and on tri-horária the peak period is concentrated between 5 pm and 10 pm.
The change reaches household customers on bi-horária or tri-horária between 1 July and 31 December 2027. It's applied remotely through the smart meter, which 99% of low-voltage customers already have. The detail that matters for EV owners: a charge scheduled for 10 pm will then spend half an hour outside off-peak. When the new schedule reaches your meter, update the timers in your car or wallbox.
VAT and contracted power eat into the saving
6% VAT only covers the first 200 kWh
Portugal's reduced 6% VAT rate on electricity applies only to the first 200 kWh in each 30-day period (300 kWh for large families), and only on contracts up to 6.9 kVA. On bi-horária, those 200 kWh are split between off-peak and fora de vazio in proportion to your usage. Everything else is taxed at 23%.
A household with an EV easily adds 150–250 kWh a month in charging alone, which pushes it past that allowance. That's why our figures use 23% VAT: in practice, it's the rate your car's kWh end up paying.
What contracted power do you need for a wallbox?
Contracted power (potência contratada, in kVA) is the maximum load your supply can take at once, and you pay a daily fee for it. A 3.7 kW wallbox usually works with 4.6–6.9 kVA. A 7.4 kW unit normally needs 10.35–13.8 kVA, and 11–22 kW chargers between 13.8 and 27.6 kVA.
Going from 6.9 to 10.35 kVA costs about €6.40 a month including VAT on the regulated tariff. At that level you also lose the 6% VAT on the first 200 kWh. For someone driving 500 km a month, this can wipe out almost the entire off-peak saving.
With 10 off-peak hours a night, most drivers don't need 7.4 kW. A 3.7 kW wallbox, or one with dynamic load balancing that throttles charging when the oven or hob is on, often lets you keep your current contracted power.
Best electricity tariffs for EVs in Portugal: supplier plans
Several suppliers offer plans aimed at home chargers. Conditions change often. The examples below reflect what was published in September 2026, and you should confirm everything directly before signing.
- EDP, Plano de Mobilidade Elétrica Verde: 20% off off-peak energy for 24 months, plus 2% off contracted power and fora de vazio. It requires buying an EDP charger, direct debit and e-billing, and only works with bi-horária. Without an EDP charger, a separate plan gives 10% off off-peak. Sign-ups are open until 31 December 2026.
- Galp, Mobilidade Elétrica: up to 20% off off-peak electricity. On Galp's 2026 price list, the off-peak list price at 6.9 and 10.35 kVA is €0.1194/kWh excl. VAT, before discounts.
- Goldenergy, Carregar em Casa: advertises €0.0830/kWh off-peak and €0.1895/kWh fora de vazio. The page doesn't say whether VAT is included, so check before comparing it with the figures in this article.
- Iberdrola, Plano Veículo Elétrico: the published conditions offered discounts on both off-peak and fora de vazio, but they applied to sign-ups until 30 June 2026. Check what's available today.
When comparing, look at the off-peak price, but also at fora de vazio and the contracted-power fee, because it's the whole household bill that changes. Time-limited discounts, like EDP's 24 months, should go into your medium-term sums.
Frequently Asked Questions
At a real-world 13.3 kWh/100 km, 1,000 km a month means 133 kWh. Using ERSE's regulated prices in force from January to September 2026 with 23% VAT, that works out at about €17.78 in the bi-horária off-peak window versus €27.05 on the flat-rate simples tariff, a saving of roughly €9.30 a month or about €111 a year. The regulated increase from 1 October 2026 adds around 0.6 cents per kWh including VAT (under €1 a month here) and leaves the saving practically unchanged. These figures exclude AC charging losses of around 10%.
Not unless you schedule the charge. Outside off-peak hours, regulated bi-horária electricity costs €0.2445/kWh including VAT, compared with €0.2034 on the simples tariff. For 1,000 km a month at 16 kWh/100 km, charging between 7pm and 10pm costs about €39.12, which is €6.57 a month more than simples and almost double the €21.39 off-peak cost. Setting the car or wallbox to start after 10pm is enough to flip the maths.
According to ERSE, the daily-cycle bi-horária off-peak window moves from 22:00–08:00 to 22:30–08:30, and weekday off-peak on the weekly cycle becomes 00:30–07:30. The change is applied remotely through smart meters between 1 July and 31 December 2027. A 3.7 kW charge starting at 22:00 would then draw about 1.85 kWh at the higher rate, roughly €0.20 extra per night or up to €6 a month if you charge daily. Once the new schedule reaches your meter, push the charging start time back to 22:30.
A 7.4 kW wallbox usually needs 10.35 to 13.8 kVA, while a 3.7 kW unit runs on 4.6 to 6.9 kVA. Moving from 6.9 to 10.35 kVA costs about €6.40 a month including VAT on the regulated tariff, and you lose the 6% VAT rate on the first 200 kWh, which only applies up to 6.9 kVA. Since a 3.7 kW wallbox delivers about 37 kWh over 10 off-peak hours, enough for more than 200 km, most drivers don't need to raise their contracted power, especially with a dynamic load-balancing charger.
There's no fixed winner, because free-market offers change often. The basic rule is to pick a daily-cycle bi-horária tariff once at least 37–40% of the household's total consumption, car included, falls off-peak. Because the network access charge is only €0.0158/kWh off-peak, every supplier's off-peak rate is cheaper. In September 2026 some plans discounted off-peak energy, such as EDP's (20% for 24 months when you buy an EDP charger) and Galp's (up to 20%), but check the current terms before signing. Compare the whole bill, including daytime rates and the standing charge, and remember that since 1 January 2026 you can switch tariff option at any time with no 12-month lock-in.
Making the most of off-peak without surprises
- Check what you use today. Go through your last few bills and estimate how much of the household's consumption already happens at night (washing machine, water heater, heating).
- Estimate the car's kWh. Multiply your monthly kilometres by real-world consumption (for example, 1,000 km × 16 kWh/100 km = 160 kWh).
- Apply the 37% rule. If home and car together put more than 37–40% of consumption in the off-peak window, bi-horária pays off.
- Schedule charging to start after 10 pm, and after 10:30 pm once the 2027 schedule reaches your meter.
- Don't raise your contracted power by reflex. First see whether a 3.7 kW or load-balancing wallbox does the job.
So how much do you save charging an EV at night in Portugal? For a car covering 1,000 km a month, a well-used bi-horária tariff is worth somewhere between €80 and €150 a year, depending on the rest of your household and charging losses. It won't change your life, but it costs nothing: one request to your supplier and a scheduled start time in the car. If you want to go further, you can pair off-peak charging with a free-market offer that includes an EV discount. And if you have roof space, you can also charge during the day on your own power once you work out how many solar panels you need to charge your car. Just rerun the numbers once the new 2027 schedule kicks in.