I-SEM Daily Briefing — 7 June 2026

Price Profile #

Std dev €63.17/MWh · Median €62.16/MWh · Periods above €150: 8 of 48 (17%)

A genuine outlier. Range €199.82. Std dev €63.17 — over twice any previous day in the run. Min €5.38 at 08:00 — a new record by €33. Peak €205.20 at 22:00.

The shape: a slow morning descent that didn’t stop. €137 at 23:00 (boundary) → €100 at 01:00 → €56 at 04:00 → €34 at 05:00 → €14 at 06:00. Through the entire working morning, prices ran €5–23: 19 consecutive half-hours below €25 from 06:30 to 15:00. Six half-hours below €10.

€5.38 is the absolute floor. That’s curtailment territory — the marginal plant was bidding the price down to keep wind from going to constraint payment.

Then the recovery. €23 at 15:00 → €57 at 15:30 → €127 at 17:00 → €174 at 17:30 → dipped back to €131 at 18:00 (a quirk in the shape) → climbed steadily to €205 at 22:00.

The single biggest within-day swing of the run: €5.38 to €205.20 inside 14 hours.

Price vs Wind #

Mean wind: 42.8% · Range: 28.9%–64.5%

Wind peaked 64.5% at 05:00 and stayed above 50% from 02:00 through 16:30 — 14 hours of sustained high wind on a Sunday with weekend demand. That’s what produced the surplus floor.

Then wind drained: 50% at 17:00 → 33% at 18:00 → 30% at 21:00 → 29% by 22:30. The evening V-into-late-peak shape produced the scarcity event. Same wind-drain mechanism as June 2 and May 29, but coming off a much cheaper base.

The structural lesson: wind surplus and scarcity can coexist in the same day, and the spread between them is the BESS opportunity. Today produced both, in textbook form.

Week in Context #

Two record-breaking days in four. June 4 broke the trough record at €37.85; June 7 broke it again at €5.38. The run is now operating in a new price regime at the bottom end.

Price Duration Curve #

Periods above €150: 8 (17% of day) · Above €200: 1 (2% of day)

8 above €150, 1 above €200. But also: 22 periods below €25. The PDC is bimodal — a sharp scarcity top (8 periods cluster €127–205) and a deep flat surplus floor (22 periods cluster €5–25), with very little in between.

A real-world example of a “scarcity day” PDC and a “surplus day” PDC on the same chart. Two distributions stuck together by the day boundary.

Peak / Off-Peak Spread #

Peak avg (07:00–22:00): €66.73/MWh · Off-peak avg: €89.64/MWh · Spread: €-22.91/MWh

−€22.91. The new most-negative reading of the run.

Peak avg €66.73 (the peak window is dominated by surplus hours), off-peak avg €89.64 (the boundary spillover at the start and the scarcity buildup at the end lift it). The metric is reading the day backwards — and the captured spread (€180) is eight times the absolute value of the headline.

If a metric tells you the day is calm and inverted while a BESS earned its best day of the run on it, the metric is wrong. Worth a stronger dashboard caveat: peak/off-peak averaging fails on bimodal days entirely.

BESS Dispatch Signal #

Simulated 1MW/2MWh battery, one optimal DAM cycle. Gross before network charges and capacity costs.

€304 gross — almost double the previous record (May 18, €168). ROI 2,609%.

Charge €6 in the morning surplus (07:00–08:30 at €5.82 avg). Discharge €186 in the late-evening scarcity (21:00–22:30 at €185.6 avg). Captured spread €180 — a number that doesn’t really compare to anything else in the run; the previous widest captured spread was May 15’s €112.

The single best argument for BESS in the data so far. One day, one cycle, €304. Three weeks of mid-range working-day BESS revenue earned on a single Sunday’s wind-shape variance.

36-day cumulative: €3,808. Top 5 BESS days: June 7 €304, May 18 €168, May 24 €163, May 17 €161, May 15 €156 — €952 from 5/36 = 14% of days = 25% of cumulative. The concentration just got more extreme; June 7 alone is 32% of the top-5 total.

Commentary #

The day BESS forecasters dream about. Range €199.82 — the biggest of the run by €81. Std dev €63.17 — over twice any previous day. Min €5.38 at 08:00 (curtailment territory). Peak €205 at 22:00 (peaker bids). Captured spread €180. Gross €304 on a single 1MW/2MWh cycle.

The structural cause: a wind shape that delivered both extremes. 14 hours of wind above 50% on a Sunday with weekend demand kept the merit order in surplus territory all morning — and the marginal plant pushed clearing prices down to €5 to keep wind from hitting constraint payment. Then wind drained from 50% to 29% across the afternoon and evening, demand built into the peak hours, and the merit order climbed into peakers.

Same mechanism as June 2’s post-holiday scarcity — wind drainage into demand peak. The difference is what came before: today’s charge was free because of 14 hours of pre-peak surplus. June 2 charged at €114. Today charged at €6. That’s the entire €158 of additional gross BESS revenue.

Five days of working-week BESS revenue earned in a single Sunday cycle. Whatever forecast cost a real operator pays to identify this kind of day, it’s worth multiples of what they’d lose on a normal day. The volatility tail isn’t a tail — it’s the business.