I-SEM Daily Briefing — 21 June 2026

Price Profile #

Std dev €27.89/MWh · Median €125.06/MWh · Periods above €150: 15 of 48 (31%)

Sunday, and demand fell further — 3,316 MW, the quietest of the week. Wind at 6.0% gave no help. The shape mirrors Saturday: overnight expensive (€140-196), daytime soft (€106-125 from 06:00-16:30), strong evening ramp. The median (€125.06) well below the mean (€134.59) reflects that cheap daytime drag. The 23:00 spike to €196.20 is already pricing in Monday’s demand.

Price vs Wind #

Mean wind: 6.0% · Range: 2.4%–11.2%

Wind was almost irrelevant today, ranging 2.4%–11.2% with no meaningful momentum. The afternoon wind tick-up to 8-11% (10:30–16:30) kept daytime prices in the €106-110 range — the softest window of the day. When wind faded back to 5-7% from 17:00 onward, the evening ramp had no brake: €125 at 17:00, €150 at 18:00, €196 at 23:00. Low wind throughout, demand doing the steering.

Week in Context #

Price Duration Curve #

Periods above €150: 15 (31% of day) · Above €200: 0 (0% of day)

15 periods above €150, zero above €200. The curve is stepped — a block of cheap periods from €106-125 through the daytime, then a rising tail into the evening. No scarcity, no floor-lifting gas crunch. The weekend demand profile written into the duration curve.

Peak / Off-Peak Spread #

Peak avg (07:00–22:00): €127.55/MWh · Off-peak avg: €146.33/MWh · Spread: €-18.78/MWh

Another negative spread, more pronounced than Saturday at €-18.78. Off-peak (€146.33) is hauled up by the overnight and the 23:00 spike (€196.20 sitting in the off-peak window). The cheap hours are in the middle of the day — not the middle of the night. Two days running where the conventional peak/off-peak framework points you in the wrong direction.

BESS Dispatch Signal #

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

Charge at €107 at 10:00 in the Sunday morning quiet, discharge at €182 at 19:30 right in the evening ramp. €96 gross, ROI 45.0%. Same weekend playbook as Saturday — exploit the cheap daytime, discharge into the evening ramp. The ROI is softer than yesterday’s 55.7% because the daytime floor wasn’t quite as deep. Still a decent day relative to the thermal-priced weekdays earlier in the week.

Commentary #

Sunday extended Saturday’s pattern — light demand, cheap daytime, expensive evenings. Mean of €134.59/MWh was up from Saturday’s €125.13, mainly because the overnight held higher (€140-177 range) and the evening ramp was steeper, ending at €196.20 by 23:00.

Wind at 6.0% contributed almost nothing. The daytime softness (€106-110 from 09:00-16:30) was purely demand-driven — Sunday morning and afternoon load is about as light as the Irish grid gets. A brief afternoon wind tick to 8-11% helped confirm the floor rather than create it. When wind faded back from 17:00, the evening ramp had no brake.

The negative spread (€-18.78) is now the second day running. Overnight prices — set by the tail of the previous day and next-day anticipation — keep beating the daytime average. The 23:00 price (€196.20) is already pricing in Monday’s demand. It’s not going to be cheap tomorrow.