Daily guide · ME · 2026-07-20
What a home battery earned in Montenegro 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 clearest pattern this week in Montenegro was the timing: every day the evening peak began at 20:00, while the cheapest window sat in daytime hours, usually starting between 08:00 and 10:00. That consistency makes the arbitrage decision simple. Charge in the morning trough, discharge into the 20:00 peak. The average spread across the week was 124,26 EUR/MWh, and the peak-hour average climbed steadily from 167,43 EUR/MWh on 13 July to 211,07 EUR/MWh on 16 July.
What varied was the cost of charging. On the strong days, cheap-window averages of 25,04 and 23,54 EUR/MWh delivered cycle values of 1,26 and 1,38 EUR. The weaker days told the opposite story: on 16 July the cheap window itself averaged 121,04 EUR/MWh, compressing the cycle to just 0,69 EUR despite the highest peak of the week. Cheap daytime power, not high peaks, drove returns.
For a 10 kWh battery at 90 percent round-trip efficiency, the week returned 6,38 EUR, consistent with roughly 388 EUR yearly. The takeaway: watch the morning trough price, not the evening peak, since that is where this week's earnings were won or lost.
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 ME this week.
€6.38
captured this week — one cycle per day, wholesale component, after losses
124.26
€/MWh average cheapest-2h → priciest-2h spread this week
≈€388
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 |
|---|---|---|---|---|---|
| 2026-07-13 | 13:00–15:00 | 25.04 | 20:00–22:00 | 167.43 | €1.26 |
| 2026-07-14 | 08:00–10:00 | 23.54 | 20:00–22:00 | 180.04 | €1.38 |
| 2026-07-15 | 09:00–11:00 | 80 | 20:00–22:00 | 197.49 | €0.98 |
| 2026-07-16 | 08:00–10:00 | 121.04 | 20:00–22:00 | 211.07 | €0.69 |
| 2026-07-18 | 08:00–10:00 | 71.36 | 20:00–22:00 | 170.5 | €0.82 |
| 2026-07-19 | 10:00–12:00 | 7 | 20:00–22:00 | 147.03 | €1.25 |
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": "ME", "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-me-2026-07-20".
The monthly European power roundup
Negative-price records, the biggest spreads, which zones were hardest to forecast — every number computed from our production data, on the 2nd of each month. No filler, unsubscribe anytime.