Prequalification

What it is (precise)

SOGL builds the process per reserve class. Article 155 requires each TSO to develop and publish an FCR prequalification process; a potential FCR provider demonstrates to the reserve connecting TSO that it complies with the technical and additional requirements of Article 154.

Article 159 does the same for FRR — compliance with the Article 158(1) minimum technical requirements, the Article 158(2) availability requirements, the ramping-rate requirements and the Article 158(3) connection requirements — and Article 162 covers RR, applying only to TSOs of LFC blocks that have implemented a reserve replacement process.

The clocks are statutory: within 8 weeks of receiving an application the TSO confirms whether it is complete; missing information must arrive within 4 weeks of the request or the application is deemed withdrawn; and the TSO has 3 months from a complete application to evaluate and decide.

The Balancing Guideline supplies the market hook, and its wording repays close reading. Article 16(1) makes successful completion of the prequalification, ensured by the connecting TSO and processed pursuant to SOGL Articles 159 and 162, a prerequisite for the qualification process to become a balancing service provider — and that cross-reference names the FRR and RR articles only, so the FCR process exists in SOGL Article 155 without being cited there.

EBGL also uses the word prequalification without ever defining it: its Article 2 list runs through 45 definitions and prequalification is absent. Keep the two steps apart as well — SOGL prequalifies reserve-providing units and groups, while qualification to become a BSP under EBGL is a separate, subsequent step for which the SOGL result is a prerequisite.

Why it matters in a real grid-scale project

The demonstration covers the full delivery chain rather than the converter alone. In Germany, the four TSOs' joint platform regelleistung.net describes the proof as covering IT, product-specific and technical requirements for FCR, aFRR and mFRR, and the concrete stages are the creation of IT and deliverance concepts, an operating test, a control-system test and the submission of certificates such as the connecting-grid-operator confirmation (ANB).

The control-system test checks the correct collection and delivery of individual data points, the accurate implementation of received setpoints, and redundant data connections; the operating test produces a power-measurement profile with a characteristic double-peak shape, and the provider runs it from its own control system. Speed, accuracy, telemetry and availability are all on trial before the first bid.

The counterparty is fixed. In Germany, prequalification is carried out exclusively by the TSO in whose load-frequency-control area the units are connected, regardless of voltage level.

For units connected in distribution grids, SOGL Article 182 adds the TSO–DSO machinery: the application must state voltage levels and connection points, the reserve type, the maximum capacity per connection point and the maximum rate of change of active power; the process for DSO-connected units has a maximum duration of 3 months from a complete formal application; and DSOs may, in cooperation with the TSO, set limits to or exclude the delivery of reserves on technical grounds such as the geographical location of the reserve-providing units (SOGL Article 182(4)).

A distribution-connected battery therefore has two grid parties in the room even though the prequalification decision stays with the TSO.

Typical values and standards

The numbers worth pinning. Application handling: 8 weeks for the completeness check, 4 weeks to supply missing information, 3 months for evaluation — standardised for FCR in SOGL Article 155(3)–(4) and for FRR in Article 159(3)–(4). Re-assessment: at least once every 5 years, and additionally when the technical or availability requirements or the equipment change (Articles 155(6), 159(6) and — a numbering trap — 162(5) for RR).

An FRR qualification granted by the reserve connecting TSO is valid for the entire LFC block (Article 159(5)). And Article 155(5) provides that compliance already verified by the reserve connecting TSO is recognised in the prequalification — the clause the grid-code overlap runs through.

Germany turns those skeleton rules into a concrete procedure. The four German TSOs — 50Hertz, Amprion, TenneT and TransnetBW — jointly operate regelleistung.net, and prequalification documents flow through the PQ portal, the central cross-TSO database.

Their published PQ conditions (version 1.05 of 5 July 2024, a non-binding English translation of the binding German text) state that a granted prequalification applies for five years, that successful prequalification of at least the minimum offer volume is a necessary prerequisite for concluding the framework agreement under which capacity and energy are then bid, and that beyond technical competence the provider's economic capability must be assured. Older German documents still carry the legacy product names PRL, SRL and MRL — the same FCR, aFRR and mFRR products under earlier labels.

How it shows up in specs, studies and contracts

Country-specificity is the rule rather than the exception. ENTSO-E maintains a page of per-country BSP and BRP requirement factsheets — the selector lists 28 countries and regions, including Germany, Ireland & Northern Ireland, Norway, Switzerland and Albania, with no Great Britain entry — structured around approval criteria, balance responsibility, contractual arrangements, application requirements, technical obligations and financial security provisions.

That structure is a usable checklist for a market-entry study; the contents differ per country, which is the point. Great Britain sits outside the SOGL and EBGL framework post-Brexit, so its route to selling reserve is a national matter, and US markets use the term market qualification for the analogous test — the EU word does not travel.

For a battery project the planning consequences are concrete. The statutory windows alone — 8 weeks plus up to 3 months per product, before any retesting — mean balancing revenue starts later than energisation, and a revenue model that assumes day-one participation in FCR or aFRR has skipped a process with its own calendar.

Each product is a separate demonstration, so a stacked strategy multiplies the test campaigns; the per-product technical specifics belong with the product entries. What the tests exercise is the plant as a controllable object: control-system integration, telemetry, and — for a battery — the state of charge needed to sustain the response across the test window, the same headroom the products then consume in service.

Common pitfalls

The biggest confusion is with grid-connection compliance. Under the connection network code NC RfG (Regulation (EU) 2016/631) the power-generating facility owner must ensure compliance throughout the facility's lifetime, and the relevant system operator may require compliance tests and simulations — a regime with its own counterparty and its own paper trail.

Balancing prequalification is a separate legal process run by the connecting TSO. The two touch in defined places: SOGL Article 155(5) lets previously verified compliance be recognised within a prequalification, and the German PQ conditions import the frequency ranges of RfG Article 13(1) into FCR prequalification. Recognition is the full extent of the overlap; neither process substitutes for the other.

The second family of errors is citing national implementation as EU law. The PQ portal, the double-peak operating test, the ANB confirmation, the framework-agreement prerequisite and the five-year validity phrasing are all German implementation, built by the four German TSOs on top of the EU skeleton — cite them as Germany, never as European law.

In SOGL itself the 5-year rule is a re-assessment obligation, triggered also by equipment and requirement changes, which Germany implements as a five-year validity period. Two smaller traps: EBGL Article 16(1) cross-references SOGL Articles 159 and 162 only, so a citation that adds Article 155 to that quote has improved the law; and SOGL says reserve connecting TSO where the German documents say connecting TSO — the same counterparty in the German context, but quote each source in its own words.