Financing Utility-Scale BESS: Securing Ancillary Service Revenues and Structuring Bankable Tolling Agreements
What Exactly Is the Lender Financing?
A 20 MW battery can be prequalified to provide balancing services, sign an optimisation agreement and produce an attractive revenue forecast. None of those steps necessarily gives a lender an enforceable claim to a future balancing-market payment. That distinction sits at the centre of utility-scale battery energy storage system (BESS) project finance.
FCR and aFRR revenue is earned under market rules, prequalification conditions, accepted bids and measured performance. Future auctions may clear at different prices, and availability or activation failures can reduce settlement. Banks therefore examine the contracts that translate market participation into payment rights, the parties legally entitled to those payments and the remedies available if the revenue chain breaks.
A bankable tolling agreement can introduce contracted availability payments, dispatch responsibilities, minimum performance standards and payment security. It can also define how the owner shares variable ancillary-service income with an optimiser. The lender then needs a security package and direct rights that remain usable when a counterparty defaults or the project enters distress.
The legal analysis is jurisdiction-specific. Germany and France operate within EU electricity-market legislation, while Great Britain and the United States use distinct market-entry, settlement and security-law structures. A template based on one market should not be treated as automatically financeable in another.
Three Rights Lenders Need to Trace
Projected gross trading income is a model input. Legal bankability turns on the actual rights held by the project company and the restrictions attached to those rights.
The Payment Claim
Who owes the tolling fee or ancillary-service settlement, when that amount becomes due and whether the project company can assign or charge the resulting receivable.
The Operating Right
Which entity controls dispatch, market bids, prequalification, metering and imbalance responsibility, and whether those permissions survive an operator replacement.
The Enforcement Route
What security, direct agreement, notice, cure period and step-in mechanism allows the lender to protect the cash flow after borrower or counterparty default.
Each layer can fail separately. A lender may hold valid security over receivables while the underlying market contract terminates. A perfectly drafted tolling agreement may generate payments payable to the optimiser rather than to the borrower. These interfaces are part of the work covered by BESS & Flexibility Markets Legal Support.
Future Ancillary Revenues and Assignable Receivables
The financing documents should distinguish a projected revenue stream from a present or future contractual claim. An FCR price assumption in a model is an estimate. A contractual availability fee owed by a creditworthy toller is a payment obligation, subject to the agreement. A balancing settlement arises only when the applicable market conditions for payment have been met.
Depending on the governing law and the location of the relevant rights, a financing structure may use security or assignment over present and future receivables, contract rights, collection accounts, shares and other eligible project assets. Creation, perfection, priority, registration, third-party notice, consent and insolvency treatment need separate local-law verification. Some project or market contracts restrict assignment, transfer or control without approval.
The contractual payment route is as important as the security grant. If the optimiser or balancing service provider is the market-facing entity, receipts may first arise in that entity’s account. The project company needs an enforceable contractual entitlement to its share, a verifiable settlement formula, agreed deductions and sufficient reporting to prove the debt owed by its counterparty.
Lenders also examine credit enhancement. A minimum availability fee, parent-company support, letter of credit, reserve account or collateral posting obligation may reduce counterparty risk when properly drafted. None converts volatile balancing prices into a guaranteed revenue stream unless a creditworthy party has expressly assumed that payment obligation.
The interaction between revenue contracts, security instruments, debt covenants and the asset’s corporate structure belongs in a coordinated Infrastructure Projects & Energy Project Finance review, particularly when the lender expects an enforceable route from operating revenue to secured repayment.
Case Study: Financing a 20 MW BESS Against Future Service Cash Flows
The Financing Problem
A 20 MW industrial BESS project required a contractual structure capable of supporting bank finance using expected cash flows from ancillary-service activities. The commercial value depended on balancing-market revenue and the legal arrangement governing the asset’s operation.
The Financing Outcome
The 20 MW project used a structured contractual model in which future ancillary-service cash flows formed part of the security arrangement supporting a €4.8 million bank loan. The result illustrates the financing relevance of revenue rights tied to a defined BESS operating model.
The legal significance lies in the link between operating contracts and financing security. In comparable projects, counsel must establish the receivable’s legal owner, the contractual payment obligation, the permitted security package and the lender’s rights following default. These points are governed by the particular transaction documents and applicable law.
The transaction lesson is practical: the projected revenue must be connected to a legally defined debtor, a measurable payment formula and a security structure that the chosen law permits the bank to enforce.
The Tolling Agreement as a Finance Document
A bankable tolling agreement does more than authorise trading. It establishes an operating relationship that the lender can analyse over the debt tenor. The starting point is the distinction between an agreed capacity-availability payment and a variable share of merchant or ancillary-service receipts.
The contract should specify the capacity made available, planned outage allowance, testing and acceptance conditions, eligible markets, dispatch authority and objective calculation of availability. It should identify when a capacity fee is earned, when it can be reduced, which failures are excused and whether a payment dispute permits set-off against unrelated obligations.
Where there is revenue sharing, the formula must identify gross receipts, market fees, balancing charges, performance penalties, charging energy, losses, optimisation fees and any permitted deductions. The project company and lender need records that reconcile bid acceptance, activation, settlement and invoice amounts. Unrestricted discretion to allocate costs to the asset weakens the reliability of the borrower’s contractual cash flow.
Bankability also depends on counterparty default and termination provisions. Notice obligations, cure periods, security calls, replacement optimiser procedures and termination compensation can determine whether a disruption becomes a manageable transition or destroys the revenue model. Contracted future payments may still stop on valid termination, so the lender should model that exposure explicitly.
For asset-protection obligations such as cycle budgets, degradation, maintenance and dispatch hierarchy, see our separate analysis of algorithmic optimisation and BESS asset degradation. Those technical restrictions also affect financeability, while this article focuses on payment rights and lender control.
Direct Agreements, Step-In Rights and the Cash Waterfall
Security over contract rights can be inadequate if a key counterparty is free to terminate the operating contract as soon as the borrower defaults. A lender direct agreement may therefore require the optimiser or toller to notify the security agent of defined defaults, honour a standstill or cure period and recognise specified security-enforcement steps.
Step-in rights may allow the lender, security agent or an approved substitute to remedy defaults, arrange continued operation or replace a contract party. Their scope must be compatible with the underlying contract, insolvency rules, energy-market registration, technical eligibility and any approval required by the TSO, regulator or network operator. A lender cannot simply inherit FCR prequalification through a contractual clause if the rules require new testing or approval.
The debt documents should also establish how collected funds are applied. A controlled account, reserve requirement and payment waterfall can direct incoming revenue toward operating costs, taxes, debt service, required reserves and permitted distributions in the agreed order. Cash sweeps and restrictions on dividends may be triggered by financial covenant tests or specified deterioration in contracted revenues.
Loan covenants should be mapped to the operating agreements: termination or material amendment of the tolling contract, loss of prequalification, substantial reduction in contracted capacity, unresolved grid-access restrictions and failure to maintain insurance may each have different consequences. Cure opportunities should be realistic for events that require regulator or TSO action.
FCR, aFRR and Grid Charges: What the Contract Cannot Control
EU Regulation 2019/943, Article 6, requires balancing markets and prequalification to give storage non-discriminatory access. Regulation 2017/2195 sets the framework for balancing service providers and balance responsible parties, while Regulation 2017/1485 addresses FCR and frequency restoration reserve prequalification. These rules support access, subject to applicable technical and procedural conditions. They do not guarantee winning bids, capacity prices or uninterrupted qualification.
For a lender, the review should identify which legal person is the balancing service provider, who bears imbalance responsibility, how assets are prequalified and who receives balancing settlements. It should also address loss or suspension of qualification, data errors, telemetry failure and penalties imposed under applicable market rules. Germany and France both require analysis against the relevant TSO and market documents.
Great Britain uses different service products and governance. NESO procures Dynamic Containment, Dynamic Moderation and Dynamic Regulation under its own service terms and prequalification processes. United States ISO/RTO storage participation follows federal and regional rules, including FERC Order 841, and requires a separate tariff and market-registration assessment. EU product names and contract clauses cannot be copied into those markets unchanged.
Network charging requires equally precise analysis. Article 18 of Regulation 2019/943 requires transparent, cost-reflective and non-discriminatory network tariffs that do not discriminate against storage. The more specific double-charging protection in Article 15(5)(b) of Directive 2019/944 concerns qualifying active customers in the circumstances defined there. Neither provision establishes a blanket exemption from every import, export or grid-related charge for a standalone utility-scale BESS across Europe.
A financeable grid-risk schedule should therefore identify the actual connection agreement, charge methodology, import and export rights, curtailed availability, compensation rules and change-in-law threshold. Disputes with a TSO or DSO must follow the relevant national review or appeal route, and a contractual indemnity can only allocate that external exposure between the project parties.
Legal Due Diligence Before the BESS Financing Term Sheet Is Signed
- Locate each receivable. Identify the debtor, legal payee, settlement trigger, deductions, contract term and whether the claim can be assigned or charged under local law.
- Test the fixed payment. Verify availability definitions, service-level exceptions, credit support, indexation and termination rights in the tolling agreement.
- Perfection and priority. Check security registration, notices, third-party consents, account control and competing creditor interests in the relevant jurisdiction.
- Negotiate direct agreements. Require appropriate notice, cure, standstill and replacement-party procedures before material operating contracts can terminate.
- Map market authorisations. Confirm the BSP or market participant, prequalification status, balancing responsibility and conditions for continued participation after an operator change.
- Read the grid documents. Test import/export capacity, connection deadlines, curtailment treatment and actual network charge classification.
- Align covenants with the contract suite. Ensure events of default, reserve accounts, payment waterfalls, distribution tests and reporting duties reflect the actual operating arrangements.
- Model revenue interruption. Include loss of balancing qualification, optimiser default, reprocurement, market repricing and regulatory change as distinct downside cases.
Conclusion: Bankability Starts With Enforceable Payment Rights
Future balancing and ancillary-service income is an attractive part of the BESS investment case. Lenders still need to know which rights produce that income, who owes the resulting payment and how the project’s contractual structure behaves under stress.
The tolling agreement establishes the payment and operating model. Security documentation deals with assignable rights and asset support under the applicable law. Direct agreements, step-in provisions and a cash waterfall provide a route to preserve value when counterparties or the borrower default. Market qualification and grid access remain subject to their own regulatory requirements.
The 20 MW, €4.8 million financing case demonstrates the commercial significance of connecting expected service cash flows with a legal security structure. For new projects, the decisive work is done before financial close: mapping the receivables, drafting the operating obligations and verifying that lenders can enforce the rights on which repayment depends.