September 2026: What the RTE consultations change for battery storage

Summary of consultation points from September 2026 applicable to BESS

September 2026 was a busy month for RTE consultations: four working groups put forward topics that directly concern battery storage system operators.

The Producers and Storage Working Group (September 10th) finalized the "forward planning" component of the future CART P&S, the PROG-MA Working Group (September 10th) confirmed the publication of adjustment volumes and system services at the site level, the RE Working Group (September 23rd) addressed the treatment of compensable limitations for storage sites, and the SSYf Working Group (September 30th) detailed the controls and penalties applicable to assets with limited energy storage (LER). Here are the key takeaways.

1. LER Assets: The operational counterpart to flexibility

This is the most structuring issue for batteries participating in the FCR and aFRR. After launching "dynamic programming" (multi-market arbitrage as close as possible to real time), RTE completes the system by offering five families of automated controls , calculated in 15-minute program steps (ISP):

• Respect for available stock : the SoC _inj and SoC _sout indicators must guarantee that the maximum activation remains deliverable over the horizon [G; G+1h15]; in case of discrepancy, the penalty is based on the higher price between the PMP aFRR and the offer price, plus the average balancing prices.
• Maintaining the TminLER (15 minutes in alert state) : penalty proportional to the missing minutes, valued at €400/MWh – a price based on the actual frequency of alert situations experienced.
• Load management constraints : P0 steps of at least 15 minutes, P0 to the fixed call program on the ISP, consistency between telemetry and programming – flat rate of €90/MW/15 min applied to the maximum amplitude of deviation.
• Power limits : P0 + reserves must never exceed the Pmax of the entity, under the same package of €90/MW/15 min.

Also worth noting on the SSYf side: the aFRR requirement for the winter of 2026-27 is on average 660 MW on the upside and 670 MW on the downside , a significant capacity resource for batteries.

2 mFRR: a new showcase for value creation starting November 18th

The SSYf Working Group presented the mFRR SPE UP product, a daily capacity tender via the RACOON platform (marginal price remuneration, pay-as-cleared), with commitments that can be met by multiple balancing entities every 15 minutes. Two points are particularly relevant to storage operators: maximum energy (Emax) is managed by the operators themselves through the hours of capacity offered, and degradation of the FCR or aFRR is prohibited for an entity committed to mFRR downwards. In other words, multi-use utilization remains encouraged, but not at the expense of already planned reserves.

3. Transparency: MA and SSYf volumes finally published at the site level

This is a recurring request from multi-site operators, and it's becoming a reality: starting in October/November 2026 , RTE will publish the volumes activated on the balancing mechanism and system services at the site level for injection and storage sites (Speed ​​Balancing API on the Data Portal, "Download SSYf data" page on the Services Portal), as soon as ISP+15 minutes. Site-level allocation keys have already been mandatory since July 16 for multi-site EDAs.

This publication is part of the planned phase- out of the RR-RE agreement, scheduled for July ^1, 2027, with the entry into force of the v3 rules: balancing and reserve managers will have the data necessary for their reconciliation, supplemented in Q1 2027 by the monthly list of sites participating in SSYf. For aggregated batteries, this eliminates a factual blind spot between RE and RR.

4 Network limitations: finally a defined framework for storage sites

The September 23rd Working Group on Energy Resources (GT RE) presented the handling of compensable limitations for storage sites, a direct extension of the BESS compensation workshops held in the spring. The principle is as follows: after notification of a limitation, the equilibrium perimeter of the energy supply (RE) is adjusted for a period of 2 hours and 30 minutes, rounded up to the nearest 15 minutes , to cover the most challenging situations – limitations notified between 4:30 PM and 11:59 PM, or successive orders with an unknown end date. Free quotas linked to an ORO (Operational Reduction Order) remain non-compensable and are not subject to any adjustment. The mechanism will be described in the CART (Regional Energy Action Plan) and the DTR (Regional Technical Document), with a consultation process in the autumn before referral to the CRE (Energy Regulatory Commission).

5 CART Producers & Storers: Forward Planning Integrated into the Contract

The working group meeting of September 10th completed the fifth phase of the CART P&S project. Storage facilities are now integrated into the predictive management framework: classification as category 2 (1 to 700 MW) or category 3 for renewable energy projects with storage, a cap on "Opportunities" of 5 days over 3 years with a three-year accounting period, commitments to correlation periods, a new, broader definition of "Unforeseen Event," and oversight of network operations (renewals, FIRC projects) through multi-year coordination (A-5/A-2) and a binding notification (A-1). Chapter 7 of the General Conditions, Chapter 4.4 of the Site-Specific Conditions (including the "Category" column), and a new DTR chapter have been rewritten accordingly. Referral to the CRE is expected in Q4 2026.

The schedule to follow

Sources: RTE consultation presentations – Producers and Storers Working Group (10/09/2026), PROG-MA Working Group (10/09/2026), RE Working Group No. 4 RE cycle v3 (23/09/2026), SSYf Working Group (30/09/2026).