Daily guide · NO5 · 2026-08-22
What a home battery earned in Norway Bergen 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.
The week split cleanly into two regimes. On 15 and 16 August, the cheap window sat near midday, at 52,05 and 56,75 EUR/MWh respectively, while evening peaks reached 118,52 and 117,52 EUR/MWh. That gap did the heavy lifting: a single daily cycle on a 10 kWh battery at 90 percent round-trip efficiency returned 0,55 and 0,49 EUR. From 17 August onward the picture flattened. Cheap averages climbed above 118 EUR/MWh and peaks moved with them, leaving cycle values between 0 and 0,12 EUR.
For the reader, this is the core lesson of arbitrage: absolute price level does not matter, the spread does. Later in the week prices were higher across the board, yet the battery earned almost nothing because charge and discharge hours were priced too closely together. The average spread of 33,63 EUR/MWh masks this concentration of value into the first two days.
The concrete takeaway: two days delivered roughly 1,04 EUR of the 1,39 EUR weekly total. Watch for wide, well-separated windows rather than headline prices, since a full year at this rhythm implies about 72 EUR.
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 NO5 this week.
€1.39
captured this week — one cycle per day, wholesale component, after losses
33.63
€/MWh average cheapest-2h → priciest-2h spread this week
≈€72
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 |
|---|---|---|---|---|---|
| 2026-08-15 | 13:00–15:00 | 52.05 | 18:00–20:00 | 118.52 | €0.55 |
| 2026-08-16 | 13:00–15:00 | 56.75 | 21:00–23:00 | 117.52 | €0.49 |
| 2026-08-17 | 02:00–04:00 | 118.08 | 08:00–10:00 | 136.55 | €0.05 |
| 2026-08-18 | 16:00–18:00 | 121.95 | 07:00–09:00 | 135.07 | €0 |
| 2026-08-19 | 04:00–06:00 | 125.19 | 08:00–10:00 | 152.55 | €0.12 |
| 2026-08-20 | 14:00–16:00 | 124.35 | 07:00–09:00 | 149.27 | €0.1 |
| 2026-08-21 | 12:00–14:00 | 137.54 | 07:00–09:00 | 161.87 | €0.08 |
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": "NO5", "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-no5-2026-08-22".
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