​Modo Energy’s October-26 forecast release allows the modelling of schedule freezes, one of the main flexible connection agreement (FCA) components causing revenue uncertainty today. Schedule freezes mean that the battery has to conform to a schedule it has committed to a certain time (often several hours) before delivery, to save protect grid operators from unforeseen swings when organising redispatch. In effect, that cuts the battery off from intraday continuous trading after that point.

Five months ago, we modelled what would happen if a schedule freeze had to remove batteries from the intraday market completely. Modelling has become more sophisticated and liquidity-aware since, allowing modelling of schedule freezes up to five-minute granularity. Although TSOs are not proposing blanket uncompensated freezes any more, many DSOs are including blanket freezes in their FCAs.

Even a single hour of freeze cuts total battery revenue by 8% to 12%, rising to as much as 17% in some years under the toughest configurations, and it lands on top of an intraday market that is already getting harder to access. This article explains our new schedule freeze and intraday methodology for dealing with intraday liquidity and volumes, as well as prices under schedule freeze conditions.

Key takeaways

• A blanket one-hour freeze cuts total BESS revenue by 8.4% (4-hour duration) to 12.0% (2-hour duration) in Modo Energy's central scenario, rising up to 26.8% at a four-hour freeze.
• A freeze has two separate effects: a volume cutoff, since 35% of all intraday volume trades in the final hour before delivery, and a price walkback that removes the most volatile periods.
• Freezes land on top of a shrinking, size-aware intraday pool. The addressable market per GW of BESS falls from 1,040 MW in 2026 to around 500 MW by the mid-2030s.
• Schedule freezes are among the largest revenue levers, and grid operator policy on them is one of the largest risk factors for BESS connections. The TSOs have now turned away from blanket three-hour freezes towards more pointed measures, but many DSOs are implementing a blanket one-hour schedule freeze.

Longer freezes do proportionally less damage per extra hour, but even a 1h freeze costs 8-12% in revenue

Modo Energy's German BESS forecast now models a schedule freeze as a single input: how many hours before delivery an asset must stop changing its position. We ran this across freeze lengths from zero to four hours, for both a 2-hour and a 4-hour duration battery, at 50 MW and 500 MW.

Going from zero to one hour costs a 2-hour duration battery 12.0% of total revenue. Stretching that same freeze to four hours adds only 14.8 further percentage points, taking the total hit to 26.8%.

The same pattern holds for a 4-hour duration asset, just at a lower level: 8.4% at one hour, rising to 17.5% at four hours. The impact is substantial in both durations, since the last hours of the intraday market are among the most value-driving for BESS in Germany.

Grid operators have moved from a blanket gate to a shorter or targeted one

Our previous article modelled a worst-case scenario: a blanket freeze at 18:00 the day before delivery, locking batteries out of the continuous intraday market entirely. That proposal cut intraday revenue by roughly 92% and total revenue by around 20%. Then, a blanket 3h schedule freeze was on the table at the TSO level, as the TSOs then said they need time to prepare their and batteries introduce new uncertainties into this process.