I-SEM Daily Briefing — 28 June 2026

Price Profile #

Std dev €49.48/MWh · Median €102.36/MWh · Periods above €150: 0 of 48 (0%)

Sunday went even further than Saturday. Mean €77.90, floor at €5.29 — barely above free. Wind stayed high (47%) but demand did the real damage: Sunday’s mean demand (3302MW) was the lowest of the week.

Price vs Wind #

Mean wind: 47.2% · Range: 41.6%–55.6%

Wind held steady in the mid-40s all day, no big spikes or troughs. With demand this low, even moderate wind was enough to flatten the merit order onto the floor.

Week in Context #

Two cheap days running — Sunday undercuts even Saturday, the low point of the week.

Price Duration Curve #

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

Flat and near-zero for most of the day — a full eight-hour stretch (09:00-16:00) under €12/MWh.

Peak / Off-Peak Spread #

Peak avg (07:00–22:00): €53.74/MWh · Off-peak avg: €118.17/MWh · Spread: €-64.43/MWh

Deepest negative spread of the week. Sunday’s “peak” window collapsed below overnight levels — it wasn’t a peak at all.

BESS Dispatch Signal #

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

Extraordinary ROI (1739%) but tiny absolute numbers — charging at €6 costs almost nothing. €220 gross is the week’s best gross profit, earned entirely because the floor fell through the floor.

Commentary #

Two days of wind glut in a row, and Sunday was worse than Saturday. €5.29/MWh at noon — essentially free power for eight straight hours. Weekend demand cratering to a 3302MW average, combined with wind sitting comfortably in the high-40s, left the system with nowhere to send the extra generation.

This is the flip side of Wednesday and Thursday’s scarcity spikes: an oversupplied system is just as extreme in the other direction. Two consecutive giveaway days is unusual even by this month’s standards — worth watching whether Monday’s return to weekday demand snaps the market back.