Manual frequency restoration reserve mFRR

What it is (precise)

SOGL Article 3(2)(7) gives the class definition: frequency restoration reserves are the active power reserves available to restore system frequency to the nominal frequency and, where a synchronous area has more than one LFC area, to restore power balance to the scheduled value.

Article 3(2)(8) then defines replacement reserves as the reserves available to restore or support the required level of FRR. mFRR itself is derived rather than defined — FRR activated by instruction rather than by an automatic control device. What SOGL does define, at Article 3(2)(143), is the manual FRR full activation time: the period between the setpoint change and the corresponding activation or deactivation of manual FRR.

The missing definition is not a drafting curiosity, it is a citation hazard. If a specification says mFRR as defined in Regulation (EU) 2017/1485, there is nothing at the other end of that pointer. The Balancing Guideline (Regulation (EU) 2017/2195) uses the long form instead: Article 20 mandates a European platform for the exchange of balancing energy from frequency restoration reserves with manual activation, which is the legal basis for MARI.

For the timing that actually binds a provider, use EBGL Article 2(30) — full activation time measured from the activation request by the connecting or contracting TSO to full delivery of the product.

Why it matters in a real grid-scale project

The 12.5-minute figure is the number to design and bid against: balancing service providers must be capable of delivering the full contracted mFRR volume within 12.5 minutes of receiving an activation request, per ENTSO-E's description of the MARI standard product. Compare that with 5 minutes for aFRR on PICASSO.

Neither figure appears in SOGL or EBGL. Both are standard-product parameters, and both sit inside the regulatory ceiling: Article 157(2)(c) of SOGL forbids an LFC block's automatic or manual FRR full activation time from exceeding the time to restore frequency, which Annex III Table 1 fixes at 15 minutes for all four synchronous areas.

Activation timing is what a battery scheduler has to plan around. On MARI, activation is either scheduled (SA), occurring at a predefined time, or direct (DA), which may happen at any point within the 15-minute interval following the scheduled activation.

Direct activation means you cannot know in advance where inside that window the instruction lands, so state of charge headroom has to be held across the whole interval rather than at one instant. Combined with the 12.5-minute delivery obligation and however long the TSO then leaves you activated, mFRR is a materially deeper energy commitment than aFRR and competes directly with energy arbitrage for the same MWh.

Typical values and standards

Numbers worth fixing: mFRR full activation time 12.5 minutes (MARI standard product, per ENTSO-E); aFRR 5 minutes (PICASSO); regulatory ceiling on both 15 minutes, being the time to restore frequency in SOGL Annex III Table 1 for Continental Europe, Great Britain, Ireland and Northern Ireland, and the Nordic area.

Both platforms support asymmetrical collection of bids, upward and downward separately, so an upward-only or downward-only offer is a normal shape rather than a special case. As of mid-2026 there is no single EU-wide statutory mFRR full activation time — Article 157(2)(c) leaves the ratio of automatic to manual FRR and both full activation times to the TSOs of each LFC block.

The provider-side obligation is in SOGL Article 158(1)(g): an FRR providing unit or group for manual FRR shall be capable of activating its complete manual reserve capacity on FRR within the manual FRR full activation time. Note what that sentence does and does not say.

It binds you to the applicable full activation time — whatever your LFC block has set — rather than to a number written in the regulation. So the compliance question is always two-step: what has the LFC block set, and what does the standard product on the platform require. The two can differ, and the tighter of them governs your design.

How it shows up in specs, studies and contracts

In market documents mFRR appears as a standard product (EBGL Article 2(28)) with its own balancing energy gate closure time — Article 2(27), the point after which a bid for a standard product on a common merit order list can no longer be submitted or updated.

What you sell splits the same way as every other reserve: balancing capacity, the volume you have agreed to hold and bid, and balancing energy, the energy actually used. Model the two separately. A capacity-only view of mFRR misses the throughput that activations put on the cells, which is the number the battery warranty is written against.

For plant specification, the 12.5-minute window is generous enough that converter speed is never the constraint — availability at the moment of instruction, telemetry and state of charge are. Write the direct-activation window into the dispatch logic explicitly, and confirm with the TSO how long a typical activation is held, because that duration and not the activation time sets the energy you must reserve. Also confirm which model applies, TSO-TSO or TSO-BSP, since EBGL Article 2(30) starts the clock at a different party's request in each.

Common pitfalls

The naming trap first: manual describes how the TSO decides to activate, not how you respond. Delivery is automatic at the plant and is measured against a 12.5-minute clock; nobody is waiting for an operator to press a button on site. The second trap is citation. As of mid-2026 SOGL contains no definition of manual FRR, only of the manual FRR full activation time, so a contract clause that defines mFRR by reference to SOGL Article 3 defines nothing. Point at EBGL Article 20's wording, or at the platform's standard product, and say which.

Third, the 15 minutes. It is the time to restore frequency from Annex III Table 1, used in Article 157(2)(c) as a ceiling on an LFC block's full activation times — it is not the mFRR product specification, and a plant engineered to 15 minutes misses the 12.5-minute MARI requirement outright. Finally, note that the 12.5-minute figure here rests on ENTSO-E's balancing-platform FAQ; the ACER decisions approving the MARI implementation framework were not consulted, so verify the parameter against your TSO's current product terms before pricing it.