Daily guide · NO3 · 2026-08-04
What a home battery earned in Norway Trondheim this week, hour by hour
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.
This week in Trondheim, a 10 kWh battery cycling once a day earned 2,73 EUR across the seven sessions, with the average peak-to-trough spread landing at 48 EUR/MWh. The daily returns were far from uniform: the strongest days were 1 August and 2 August, worth 0,75 EUR and 0,73 EUR respectively, while 30 July delivered just 0,09 EUR. The difference came down to how cheap the overnight-to-midday trough ran. On 1 and 2 August the cheap window averaged 9,41 and 6,50 EUR/MWh against peaks near 94,12 and 88,28 EUR/MWh; on 30 July the trough held at 68,80 EUR/MWh, leaving almost nothing to arbitrage.
For the reader, the pattern is clear: peak prices stayed relatively stable in the 82 to 94 EUR/MWh band all week, so your earnings were decided almost entirely by how low the charging window fell. Cheap periods clustered around midday, typically starting between 11 and 15.
The concrete takeaway: at 90 percent round-trip efficiency, this cadence projects to roughly 142 EUR a year. Charge only when the trough genuinely collapses, and skip flat days.
A home battery makes money on one thing: the gap between the day's cheapest and priciest hours. Charge low, discharge across the evening peak instead of buying it, repeat daily. The size of that gap is set every afternoon at the day-ahead auction — so it's measurable, not hypothetical. Here is what one full daily cycle of a 10 kWh battery (at 90% round-trip efficiency — losses included, unlike most brochures) would have captured in NO3 this week.
€2.73
captured this week — one cycle per day, wholesale component, after losses
48
€/MWh average cheapest-2h → priciest-2h spread this week
≈€142
a year at this week's spreads — the honest run-rate, not the best-day fantasy
Day by day: the two windows that mattered
| Day | Charge (2h) | at €/MWh | Discharge (2h) | at €/MWh | Cycle value |
|---|---|---|---|---|---|
| 2026-07-28 | 14:00–16:00 | 32.8 | 07:00–09:00 | 82.18 | €0.41 |
| 2026-07-29 | 13:00–15:00 | 60.26 | 17:00–19:00 | 88.24 | €0.19 |
| 2026-07-30 | 15:00–17:00 | 68.8 | 20:00–22:00 | 86.8 | €0.09 |
| 2026-07-31 | 13:00–15:00 | 55.72 | 18:00–20:00 | 92.64 | €0.28 |
| 2026-08-01 | 13:00–15:00 | 9.41 | 19:00–21:00 | 94.12 | €0.75 |
| 2026-08-02 | 13:00–15:00 | 6.5 | 18:00–20:00 | 88.28 | €0.73 |
| 2026-08-03 | 11:00–13:00 | 53.85 | 22:00–24:00 | 91.1 | €0.28 |
Local time, hourly auction means. Days where charging was negative-priced mean you were paid to fill the battery.
Do it automatically
The windows move every day — automation is the whole game. One API call returns a cost-optimal schedule your inverter or energy manager can follow, and there's a full battery simulator to backtest your exact capacity, power and cycle limits against realized prices before you trust it:
curl -X POST -H "Authorization: Bearer YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"zone": "NO3", "capacity_kwh": 10, "max_power_kw": 5,
"round_trip_efficiency": 0.9, "max_cycles_per_day": 1}' \
https://voltcast.com/api/v1/optimize/batteryHome Assistant users get the schedule as a sensor via the integration. And because the value depends entirely on tomorrow's spread, the P10–P90 forecast — scored publicly every day — tells you whether tomorrow is worth a deep cycle at all.
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/battery-arbitrage-no3-2026-08-04".
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