RSF Qualification for BESS in Romania: Technical Performance and Bankability

Practical guidance on RSF qualification for BESS in Romania: technical performance as a bankability gate.

Romania is entering a new phase in the regulation of battery energy storage systems (BESS). While the legal framework for system services has existed for several years, Transelectrica has now moved decisively from theory to execution.

In early 2026, Transelectrica published a draft operational procedure governing the verification of RSF (Frequency Restoration Service) for the technical qualification of energy storage installations.

Although this is not a new ANRE regulation, it is a brand-new operational instrument that fundamentally changes how BESS projects are evaluated, qualified and - ultimately - monetised.

This article explains what the procedure does, why it matters, and how it directly affects bankability, contracts and financing.

1. From Regulatory Framework to Operational Reality

Until now, RSF qualification for storage projects existed mainly at the level of:

• regulatory eligibility,
• high-level technical requirements,
• and commercial expectations embedded in project models.

The new Transelectrica procedure changes this by:

• defining how RSF capability is verified in practice,
• specifying what is tested, measured and documented,
• and establishing when qualification can be suspended or re-assessed.

In short, RSF is no longer a declared capability. It is a demonstrated operational behaviour.

2. What RSF Really Means - Beyond the Acronym

RSF (Frequency Restoration Service) is often described generically as "fast frequency response". That description is incomplete.

Short definition

RSF is the ability of a resource to stabilise grid frequency by injecting or absorbing power rapidly in response to frequency deviations.

Operational reality

From Transelectrica's perspective, RSF means:

• response within defined timeframes,
• bidirectional behaviour (up and down),
• repeatability under real operating conditions,
• measurability, with verifiable data and logs.

Commercial consequence

A BESS project only gets paid for RSF if:

• it responds correctly,
• every time it is called,
• and can prove that it did so.

This is the core shift introduced by the draft procedure.

3. Why This Procedure Matters for BESS Projects

The new procedure directly impacts four critical dimensions of a storage project:

3.1 RSF becomes a qualification gate

A project can no longer rely on nominal power or vendor specifications. A "50 MW BESS" is irrelevant if:

• response is delayed,
• control is unstable,
• or performance cannot be documented.

3.2 Control architecture is now decisive

Qualification depends on the entire control chain, including:

• PCS performance,
• EMS logic,
• SCADA integration,
• SOC management strategy,
• telecommunications latency and reliability.

Weak links anywhere in this chain can lead to qualification failure or suspension.

3.3 Bankability is directly affected

From a lender's perspective, RSF qualification now represents:

• a technical risk, and
• a revenue continuity risk.

Failure to qualify - or loss of qualification - directly impacts cash flow assumptions.

3.4 "RSF-ready" is no longer a marketing claim

The procedure turns RSF from:

a slide in a pitch deck
into
a tested, monitored and enforceable obligation.

4. Scope of Application: Not Just Initial Qualification

One of the most important aspects of the draft procedure is its ongoing applicability.

It applies not only to:

• initial technical qualification, but also to situations such as:

• retrofits and modernisations,
• changes in UFR/GFR configuration,
• software or control logic updates,
• cases where monitoring indicates that RSF is not effectively delivered.

Practical implication

Qualification is not permanent. It is conditional on continued compliance. Any material change to the system may trigger re-verification.

5. Monitoring, Evidence and the End of "Trust Me"

The procedure places strong emphasis on:

• measurement accuracy,
• logging and traceability,
• and objective verification.

From an operational standpoint, this means:

• response events must be recorded,
• timestamps and data integrity matter,
• discrepancies between declared and actual behaviour are actionable.

This effectively removes the "trust-based" element from RSF delivery.

6. Legal and Contractual Consequences

The introduction of this procedure has immediate contractual implications.

6.1 EPC and OEM contracts

Contracts must clearly allocate responsibility for:

• RSF-related performance parameters,
• control system integration,
• testing and tuning obligations,
• remedies if qualification is not achieved.

6.2 O&M agreements

O&M scope must cover:

• maintaining RSF-critical parameters,
• SOC management discipline,
• change management for software and firmware updates.

6.3 Financing documentation

From a bankability perspective, RSF qualification now supports:

• technical due diligence findings,
• conditions precedent,
• and ongoing compliance undertakings.

7. Public Consultation: A Narrow but Important Window

The procedure is currently published as a draft and is subject to public consultation.

Key dates

Deadline for submitting comments: 26 January 2026 (as announced by Transelectrica)

This is a critical opportunity for:

• developers,
• integrators,
• equipment suppliers,
• investors and lenders,
• to ensure that:

• requirements are technically realistic,
• testing criteria are clear,
• and operational obligations are proportionate.

After finalisation, the procedure will define market practice, not just internal TSO workflows.

8. Key Takeaway for the Market

In one sentence:

RSF qualification for BESS in Romania has moved from theory to enforcement.

ANRE provided the legal framework. Transelectrica is now defining the operational reality.

For BESS projects, this means:

• technical readiness is no longer optional,
• control architecture is a core value driver,
• and qualification status is directly linked to revenue and financing.

RSF just became very real.

How Grigorescu Partners Can Assist

We support BESS developers, investors and technology providers in Romania with:

• RSF qualification strategy,
• control architecture risk reviews,
• EPC & OEM contract structuring,
• bankability and lender-side legal support,
• regulatory disputes and qualification challenges.

A one-stop legal and project advisory partner for serious energy storage projects.

Explore our Insights, review our Services, or contact us to discuss a specific BESS project and its qualification path.

Grigorescu & Partners

Get our insights. No spam

Short, practical notes on energy regulation, project bankability, corporate work and tax disputes - written from mandates, not theory.