ACER Plans Major Changes After Pan-European Intraday Power Auction Failure
IDA1's cancellation during the week of August 17 left Europe without a functioning pan-European intraday power market and ACER committing to unspecified changes.
EU energy regulator ACER is planning "major changes" to address technical problems that forced the cancellation of the first pan-European intraday power auction, IDA1, during the week of August 17 (2026-08-17), a spokeswoman told Montel on Thursday (2026-08-20). Montel's reporting names the Epex Spot exchange in connection with the failure.4
Pan-European intraday auctions are not interchangeable with the bilateral contracts that dominate cross-border power trading. The mechanism allows grid operators and power traders to match supply and demand across national borders inside the delivery day, through a single coordinated clearing process.4
IDA1 was the first time such an instrument had been run at pan-European scale. Cancelling it before a single successful session means it has yet to demonstrate it can operate under live market conditions. Participants who had planned to use it for intraday balancing or short-position management have no equivalent cross-border instrument while it stays offline.4
But ACER's public statement offered no specifics on what went wrong. The spokeswoman did not identify whether the fault lay in Epex Spot's exchange infrastructure, the market coupling algorithm that allocates cross-border capacity, or the data interfaces between national transmission system operators.4
Each diagnosis carries a different remediation timeline. Exchange-level software problems can sometimes be resolved within days. Failures in the coordination layer spanning multiple TSOs from different jurisdictions are harder to isolate and cannot be fixed by a single actor. Without knowing the root cause, there is no public basis for estimating when IDA1 will relaunch.4
That uncertainty is significant. A new intraday mechanism needs to accumulate liquidity quickly to become useful. An early outage with no confirmed return date makes it harder to establish the trading patterns that give an instrument depth. Participants who might otherwise route intraday balancing through IDA1 have little incentive to restructure their workflows around a product with no timeline.4
The failure arrives alongside several open ACER workstreams. The agency intends to decide by January 20 on new frequency containment reserve rules for the continental Europe synchronous area, aimed at reducing blackout risk.3 A public consultation on growing power purchase agreement markets across the EU opened on Tuesday (2026-05-19).1 And ACER has urged southeast European transmission system operators to accelerate grid upgrades after sharp power price spikes in the region in 2024.2
All three workstreams run into the same underlying difficulty: EU energy market rules are designed for an integrated single market, while the physical grid and the institutions that operate it remain nationally managed. IDA1's collapse on its first run is an operational illustration of that gap.4,3,2,1
The next concrete signals are a relaunch date, a technical specification of what ACER requires from Epex Spot before the auction can operate again, and whether any independent review of the root cause is ordered. None has been provided. The "major changes" ACER's spokeswoman committed to on Thursday (2026-08-20) remain, for now, without defined content.4