Daily guide · DE-LU · 2026-09-11
Charging an EV in Germany-Luxembourg this week: what the prices actually said
All numbers computed from the week's published auction results at publication and frozen — this article is an honest snapshot, not a page that rewrites itself. Reproduce via the API.
The clearest signal this week is the gap between midday and evening. The cheapest charging window averaged 25,85 EUR/MWh, while the evening peak averaged 208,43 EUR/MWh — a difference of 88 percent. On several days the midday window fell below zero, with 5 September averaging -15,47 EUR/MWh and 4 September and 6 September both slightly negative. The window mostly opened around midday, between 12:00 and 13:00.
Evenings told the opposite story. Prices climbed through the week and peaked on 10 September at 380,06 EUR/MWh, well above the earlier evenings such as 5 September at 85,95 EUR/MWh. For an EV owner, this means the timing of a charge mattered far more than the day chosen: charging into the evening peak, especially late in the week, was consistently the most expensive option.
The concrete takeaway: shifting a typical 150 kWh weekly charge from the evening peak into the midday window was worth 27,39 EUR this week, or roughly 1.424 EUR over a year. Setting a charger to start around midday captures most of that gap without any manual attention.
Every day at 13:00 CET, an auction sets electricity prices for every hour of tomorrow — separately, for each European bidding zone. Those prices routinely differ by a factor of two to three within a single day, because solar floods the middle of the day and demand peaks in the evening. If you charge an EV, that spread is money: the car doesn't care when it charges, only that it's full by morning. This is what the spread looked like in DE-LU this week.
88%
cheaper to charge in the best 3h window than at the evening peak, on average this week
25.85 vs 208.43
€/MWh: best window vs 18–21h evening habit (week average)
≈€1424
a year on the wholesale component, for 150 kWh/week of charging at this week's gap
Day by day: when the cheap window actually fell
| Day | Cheapest 3h window | Window avg €/MWh | Evening 18–21h | Gap |
|---|---|---|---|---|
| 2026-09-04 | 13:00–16:00 | -0.1 | 126.39 | −100% |
| 2026-09-05 | 13:00–16:00 | -15.47 | 85.95 | −118% |
| 2026-09-06 | 12:00–15:00 | -1.13 | 214.58 | −101% |
| 2026-09-07 | 13:00–16:00 | 45.47 | 226.46 | −80% |
| 2026-09-08 | 12:00–15:00 | 6.81 | 232.89 | −97% |
| 2026-09-09 | 13:00–16:00 | 67.2 | 192.69 | −65% |
| 2026-09-10 | 12:00–15:00 | 78.18 | 380.06 | −79% |
Local time. Notice the window MOVES — sometimes after midnight, sometimes midday when solar peaks. A fixed night tariff catches some of this; following the auction catches all of it.
Automate it in ten minutes
You don't need to read auction results at 13:00 every day — ask the API for the cheapest window and let your wallbox follow it. One call:
curl -X POST -H "Authorization: Bearer YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"zone":"DE-LU","duration_minutes":180,
"objective":"balanced",
"tariff":{"grid_fee_eur_kwh":0.10,
"supplier_markup_eur_kwh":0.02,
"vat_percent":25}}' \
https://voltcast.com/api/v1/optimize/cheapest-window
Home Assistant users: the Voltcast integration
exposes the recommended-window timestamp plus charge_now and
negative_price_incoming; evcc users get a ready-made tariff config.
Enter the variable grid fee, supplier markup and VAT from your bill for cost context.
Optional carbon/balanced modes are experimental trailing historical production-profile
heuristics—not weather-conditioned forecasts or emissions claims. The
Home plan (€9/mo) covers one
zone of your choice with 7-day forecasts, these action signals and the battery simulator;
public pages and widgets let you inspect the data before subscribing.
And if you want to charge on a forecast of tomorrow before the auction even publishes, that's the
P50 curve — scored publicly every day so you know exactly
how much to trust it.
Method & citation. Prices are hourly means of published day-ahead auction results (native 15-minute periods averaged; ENTSO-E/SMARD, attributed). Wholesale-price component only — grid fees and taxes come on top and vary by supplier. Cite as "Voltcast Research, voltcast.com/guides/ev-charging-de-lu-2026-09-11".
Next issue 2 Oct
The European power roundup. Once a month. Real numbers.
Negative-price records, the month's widest spreads, the zones we failed to forecast — computed from the same production recorders as the API. No filler. Unsubscribe in one click.
- ✓ Negative hours and the cheapest zones
- ✓ The month's widest day-ahead spreads
- ✓ Forecastability ranking — where we missed
Get the next issue in your inbox.
No account. Double opt-in. Nothing else, ever. Privacy.