Yesterday’s French balancing market in RTE showed a surprisingly unusual pattern over the day.
The intraday UPWAP ranged from -13.0 €/MWh at 02:30 to 183.5 €/MWh at 21:00.
What makes the day interesting is not just the negative price, but the fact that the strongest upward move came unusually late, after the main evening ramp had already started to pass.
After going through the imbalance, activation, generation mix and wind forecast data, the day seems to break down into 4 phases:
1) Negative prices during the night
At 02:30, UPWAP fell to -13.0 €/MWh.
At that moment:
load was only 46.4 GW
wind output was 11.9 GW
hydro was 6.3 GW
pumping load was about 3.3 GW
cross-border physical exchange was around -15.1 GW
The reference balancing prices were also negative (PRE+ -14.35 €/MWh, PRE- -11.57 €/MWh).
So this looks less like a stress event and more like a system that was simply very loose overnight, with little value for upward flexibility.
2) Morning stress from 06:00 to 08:00
This part is interesting because the system tightened even though wind was not weak.
UPWAP moved into the 105–116 €/MWh range while:
load increased from 48.5 GW to 56.0 GW
solar was still essentially absent
hydro rose from 6.9 GW to 8.8 GW
At 06:45, the onshore wind actual was actually about 0.8 GW above the intraday forecast, so this looks more like a morning ramp / flexibility issue than a simple renewable shortfall story.
3) Midday returned to very low or negative prices
Around 11:15–11:45, UPWAP went negative again:
-1.0 €/MWh at 11:15
-3.0 €/MWh at 11:30
-3.0 €/MWh at 11:45
At 11:30:
load was 57.9 GW
wind was 13.4 GW
solar was 7.1 GW
system imbalance was +202.8 MWh
downward balancing prices were deeply negative (PMP Baisse -72.7 €/MWh)
This looks like a fairly straightforward surplus episode: strong renewable output and significant downward activation.
4) Evening ramp, then a very odd 21:00 spike
From 18:00 to 19:15, the day behaved more like a classic evening stress event:
load rose from 55.1 GW to 59.9 GW
solar fell from 1.57 GW to 0
hydro ramped from 10.0 GW to 14.8 GW
UPWAP climbed from 109.7 to 122.3 €/MWh
Onshore wind also moved below the intraday forecast through that whole period, with the gap widening from about -148 MW at 18:00 to -575 MW at 19:15.
But the strangest move came later:
At 21:00, UPWAP jumped to 183.5 €/MWh, even though:
load had already eased back to 54.7 GW
the system tendency was downward
there was still 112.7 MW of downward aFRR and 99 MW of downward RR
At the same time, there was still a small amount of upward specific mFRR activated (35.5 MW) at a very high price.
So my read is that the 21:00 spike was not a broad system shortage, but more likely a case where a small pocket of upward flexibility became very scarce and very expensive, even while the overall balancing direction was not purely upward.
To me, the most interesting part of the day is not the negative price itself, but the late 21:00 spike.
The data suggests that the move may not have been caused by a broad system shortage, but rather by a very localized scarcity of upward flexibility, where a small amount of upward reserve had to be activated at a very high price.
Curious how others here would interpret that 21:00 move in particular.
Source: ArcusRise