Daily guide · NO3 · 2026-09-09

Negative-price watch Norway Trondheim: this week's floor, and what's ahead

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.

Despite the negative-watch framing, Trondheim gave no reason for alarm this week. The floor landed at 26,49 EUR/MWh on 6 September at hour 13, comfortably above zero and above the 10 EUR/MWh threshold we track for soft-price stress. There were zero negative hours and zero hours below 10 EUR/MWh across the week, and our model put the seven-day probability of a negative print at 0.

For readers positioned around Trondheim, this means the downside tail stayed closed. A midday low near 26 EUR/MWh reflects a market with slack but no genuine oversupply, so there was no window this week where consumption or storage charging could have captured near-free power. The absence of any sub-10 hours also removes the usual signal that curtailment or export constraints are building.

The concrete takeaway: this is a quiet week to note, not act on. Year-to-date, Trondheim has recorded 9 negative periods, so the floor mechanism is real even if dormant now. Keep flexible loads ready, but there was nothing this week that rewarded shifting demand into the low hours.

When wind and solar produce more than a zone can consume or export, the day-ahead auction clears below zero — producers literally pay consumers to take power. Negative prices went from curiosity to structural feature across Europe, and for anyone with flexible load or storage they're the most interesting hours of the year. Here's where NO3 stands.

26.49

this week's floor (€/MWh), 2026-09-06 at 13:00 local

0 / 0

hours below €0 / below €10 this week

negative delivery periods in 2026 so far (NO3)

The forward view

Our negative-price risk model (Brier-scored daily against climatology — record on /accuracy) currently puts the peak probability of a sub-zero period in NO3 over the next 7 days at 0%. That number updates daily via GET /v1/risk/negative/NO3 — a 14-day calendar of per-15-minute probabilities.

Never miss one again

The useful pattern isn't watching a dashboard — it's a webhook that fires when tomorrow's auction clears negative anywhere in your zone:

curl -X POST -H "Authorization: Bearer YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"event": "negative_prices", "zone": "NO3", "url": "https://your-app/hook"}' \
  https://voltcast.com/api/v1/webhooks

It delivers seconds after the 13:00 CET publication, HMAC-signed. Journalists and analysts: the live NO3 tracker has the all-time records, monthly history and a CSV download — free to cite with attribution. Home+ can download its entitled interval prices and forward risk directly to Excel from the API; the full 2015+ archive remains a Pro+ bulk export.

Live NO3 prices → All daily guides → Start with Home →

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/negative-watch-no3-2026-09-09".

Next issue 2 Oct

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✓ Negative hours and the cheapest zones
✓ The month's widest day-ahead spreads
✓ Forecastability ranking — where we missed

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