Daily guide · IE-SEM · 2026-09-03

Negative-price watch Ireland (SEM): 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, this week gave no material to work with on the downside. The lowest settled point was 125,2 EUR/MWh, recorded on 31 August 2026 in hour 11 — a midday reading that sits well above any level of concern. There were zero negative-price hours across the week and zero hours below 10 EUR/MWh, so the SEM floor stayed comfortably positive throughout.

For the reader, this means the near-term risk of curtailment economics or negative settlement simply did not materialise. The modelled probability of a negative period over the next seven days is 0, which aligns with the observed week rather than contradicting it. In context, the SEM has logged only 4 negative periods year-to-date, so the underlying frequency remains low.

The concrete takeaway: with the week floor at 125,2 EUR/MWh and no sub-zero or sub-10 hours, there is nothing on the immediate horizon requiring defensive positioning. Keep the watch active given the 4 year-to-date periods, but treat this week as a firmly positive-priced baseline rather than a warning.

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 IE-SEM stands.

125.2

this week's floor (€/MWh), 2026-08-31 at 11:00 local

0 / 0

hours below €0 / below €10 this week

4

negative delivery periods in 2026 so far (IE-SEM)

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 IE-SEM over the next 7 days at 0%. That number updates daily via GET /v1/risk/negative/IE-SEM — 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": "IE-SEM", "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 IE-SEM tracker has the all-time records, monthly history and a CSV download — free to cite with attribution. For the systematic view (which hours, which seasons, how deep), the full 2015+ archive is one bulk export away.

Live IE-SEM 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-ie-sem-2026-09-03".

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.