Which electricity contract suits your battery?
Every electricity contract from Engie, Luminus and Eneco since 2022, calculated month by month with a real home battery.
Tariffs up to October 2026 · source: V-test (VREG) and EPEX day-ahead prices
With a smartly steered battery, a dynamic contract is cheapest. The cheapest variable contract with a monthly price comes a close second.
In 2023 the cheapest variable contract was even cheaper; in 2026 dynamic pulls ahead as prices swing more. A fixed contract makes your battery save the most, but your bill stays highest. Choose your contract on your bill, not on what your battery saves.
Household with solar panels and a 10 kWh battery. Single-rate meter, no day/night tariff. Capacity tariff and VAT included.
What do you pay per year, with and without a battery?
Household with solar panels: 2,860 kWh offtake and 2,250 kWh injection per year. The light bar is your bill without a battery, the solid bar with one.
Median of all offers in each month.* Energy, grid tariff, levies, fixed fees and capacity tariff, incl. VAT. **2026: January to October.
The cheapest offer of that type each month, as if you always had the cheapest contract. Energy, grid tariff, levies, fixed fees and capacity tariff, incl. VAT. **2026: January to October.
How have prices changed since 2022?
After the 2022 crisis, all prices fell by half. Dynamic was cheapest in almost every month, fixed usually the most expensive.* Since the summer of 2026, prices have been rising again.
c€/kWh you pay, everything included except the capacity tariff, incl. VAT · line = median, band = cheapest to most expensive offer
c€/kWh you get for power you feed into the grid · median of the offers
What new customers paid in that month. Variable and dynamic prices calculated afterwards with the real market prices.*
Your questions, answered briefly
Which contract suits which battery? Does your battery steer on market prices? Then a dynamic contract. Does it only maximise self-consumption? Then the cheapest variable contract with a monthly price. A fixed contract almost always gave the highest bill.
| Your battery | Best contract | Yearly bill in 2025 |
|---|---|---|
| Plug-in battery, self-consumption only | Variable, monthly price | €781, against €870 dynamic and €888 fixed |
| Installed battery, self-consumption only | Variable, monthly price | €645, against €716 dynamic and €709 fixed |
| Installed battery that steers on market prices | Dynamic | €643: the battery charges cheaply from the grid and discharges when prices are high |
| Certainty above all | Fixed | The battery saves the most (€327), but your bill is the highest |
Cheapest offer of each month, single-rate meter. Variable with a monthly price: the price follows the average day-ahead price over the month. The cheapest variable contract did so in every month of 2025.
How much do the suppliers differ? Their cheapest offers are close together. The difference is in the product you pick: between the cheapest and a typical variable contract there was €88 a year in 2025.*
Cheapest offer per supplier, c€/kWh offtake, incl. VAT*
Should I switch contracts often? Compare twice a year. Switching is free, and the cheapest variable contract changed supplier 11 times in 57 months.
In 82% of the months, the cheapest variable contract without a battery was also the cheapest with one. So there is no need to hunt for a special "battery contract": the contract type is what matters.
Is smart steering becoming worth more? Yes. The gap between the highest and lowest market price of a day grew from 9.2 c€/kWh in 2024 to 17.5 c€/kWh in 2026.
Average gap between the highest and lowest market price of a day, c€/kWh excl. VAT
With smart steering, the 10 kWh battery saved €250 in 2023 and €337 in 2025. Up to October 2026: already €402.
How we calculated
- Each month: every offer for new customers from Engie, Luminus and Eneco according to the regulator's V-test, single-rate digital meter.
- Fixed: the fixed price. Variable: the formula with the real market average of the month or quarter. Dynamic: the formula per quarter-hour.
- Battery of 10 kWh / 5 kW and plug-in battery of 2 kWh / 0.8 kW, 90% efficiency, simulated quarter-hour by quarter-hour with the engine of the calculator. Smart steering does not charge above the month's highest peak.
- Today's grid tariffs, levies and capacity tariff (minimum 2.5 kW) in Ghent (Fluvius Imewo), for every year: so only the supplier's price differs.
- 2022 is left out of the yearly figures: during the crisis there were few fixed contracts and only Engie had a dynamic contract.
* For 46% of variable contracts, the price follows Endex, the market's futures prices. We don't have those yet: we calculated these contracts with the day-ahead price of the same period. We will fix this soon. Statements about the cheapest variable contract with a monthly price don't depend on it: that one follows the monthly average day-ahead price.
What does this mean for your consumption?
Compare fixed, variable and dynamic with your own meter data. Free.
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