Romanian BESS in 2027–2028: stand-alone or hybrid, and which revenues are bankable?

A BESS is not investable merely because spreads between electricity prices are wide. Potential revenue from arbitrage, system services and optimisation of an associated renewable plant must fit the project’s grid rights, qualification rules, market-access agreements and technical performance. For 2027–2028, the developer's question is not “how much can 1 MW theoretically earn?” but which revenue can actually be delivered, by whom and with what downside if prices deteriorate?

Stand-alone or co-located: what changes legally?

A stand-alone BESS has its own development and connection position or a separate technical configuration; a co-located project integrates storage with a solar or wind plant and may share infrastructure. The choice can change connection applications, approved import/export capacities, contracts, site rights and permits. The ANRE Connection Regulation expressly accommodates storage installations within its definitions and procedures.

For a hybrid project, do not assume battery power can be added without reviewing the ATR. Examine export limits, approved absorption, control logic and any simultaneous operating restrictions affecting generation and discharge. Where the configuration changes after ATR issuance, determine whether a revised solution study, ATR update or other filing is needed.

Where can battery revenues actually come from?

Arbitrage means purchasing or charging at lower prices and selling or discharging at higher prices, net of efficiency losses, tariffs and degradation. Balancing and system services may provide separate income streams, but access depends on technical qualification, operator requirements and suitable market-facing arrangements. A model that adds every revenue stream in full without accounting for competition for the same MW can count fictitious revenue twice.

Market rules and participant obligations derive from Electricity Law No. 123/2012, ANRE regulations and transmission system operator requirements. Historical OPCOM data inform market scenarios, but cannot guarantee future trading margins. Ancillary-service revenue should not be presented as “guaranteed” merely because the battery can respond quickly.

Which technical inputs drive contract risk?

The model should incorporate MW power, usable MWh, duration, round-trip efficiency, cycles, year-by-year degradation, auxiliary consumption, contracted availability and thermal operating conditions. Qualification and operation also require attention to technical conformity, testing and notification procedures; BESS should be assessed under applicable ANRE storage and system-service requirements, not only an OEM datasheet.

OEM and EPC performance metrics must become enforceable acceptance tests and remedies: minimum usable energy, available power, availability, efficiency, degradation warranty, liquidated damages and liability caps. A revenue projection assuming 100% availability cannot be assessed separately from the actual agreements defining availability and downtime.

What does a bankable optimiser agreement look like?

An optimiser may trade available energy and capacity, handle nominations or access certain markets on behalf of the owner or through a qualified market participant. Verify who actually holds market-access rights, bears imbalance costs, pays fees and assumes responsibility for technical constraints. An attractive revenue-share percentage may underperform if the calculation base, permitted deductions and netting rules are undefined.

The agreement needs performance obligations, cycling restrictions, market priorities, reporting and algorithm transparency, audit rights, termination mechanics, change in law, lender step-in and data access. A profit projection is not a revenue guarantee. For bankability, lenders may demand control over optimiser replacement and a revenue structure compatible with debt repayment.

Are Romanian BESS grants available, and what do they solve?

On 6 March 2026, the European Commission announced approval of a EUR 150 million Romanian state-aid scheme for storage. EU approval does not automatically make every project eligible or mean a grant has been awarded. Eligibility, tender criteria, eligible costs, delivery obligations and clawback risk must be reviewed under the applicable national scheme and actual grant agreement.

A grant can improve CAPEX economics without resolving ATR risk, merchant revenue uncertainty or financing of the remaining equity. Investors also need to check whether subsidy conditions restrict ownership changes, aid cumulation, asset use or commissioning dates. These restrictions may later matter on exit.

How should BESS bankability be tested?

An investable package must demonstrate four links: legal import/export rights, access to the proposed revenue streams, technical ability to deliver them and enforceable contracts monetising that ability. The model should be stress-tested for narrower spreads, stronger competition, grid constraints and faster degradation. A two-hour project may respond very differently from a four-hour project; there is no universally superior duration.

The useful deliverable is a BESS Revenue & Contract Bankability Report, putting optimiser assumptions, OEM/EPC obligations, grid risks and financing conditions on one page. Without a coherent chain, “revenue-ready” remains a commercial label rather than a legal or financing conclusion.

Hypothetical example: the investment decision

*Hypothetical example, not a reference to an actual project.*

A hypothetical 50 MW/100 MWh BESS forecasts arbitrage and balancing revenues. Its optimiser agreement proposes a 70/30 revenue split but fails to define trading deductions and allows cycling beyond OEM assumptions. Risk cannot be assessed from the headline revenue-share percentage: degradation modelling, a contractual definition of net revenue and evidence of market-access rights are required. This illustrates the issue, not an earnings forecast.

Developer Action Checklist: what should be checked in the next 30–90 days?

1. Compare stand-alone and hybrid structures against the ATR, approved import/export rights and permits. 2. Validate revenue assumptions without double-counting the same capacity across markets. 3. Tie the model to degradation, OEM tests, availability and EPC obligations. 4. Review optimiser fees, data, imbalances, revenue share and lender step-in. 5. Test grants and subsidy conditions solely against the actual scheme documents.

Conclusion and next steps

The best battery is not necessarily the one with the highest forecast revenue. It is the one whose revenue can be demonstrated, contracted and financed in a realistic case. Bankability emerges when grid rights, technology, the commercial operator and the lender rely on compatible assumptions.

Request a project-specific assessment. Grigorescu & Partners can review the key documents and prepare a focused risk, deadline and action report. Discuss a mandate or Email us the project details.

Primary sources and verification date

*Analysis updated on 12 October 2026.*

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Editorial note: For general information, not project-specific legal advice. Applicable rules depend on project history, documents, contracts and subsequent amendments.