How to assess whether a BESS project is truly bankable?

The bankability of a large-scale battery energy storage (BESS) project — both as a stand-alone asset and in a hybrid configuration with a renewable source (RES) — means the project's ability to obtain debt financing on acceptable terms. It does not depend solely on the level of revenues, but above all on their predictability, their resilience to market changes and the quality of the operating and financial model.

The structure of the project and the credibility of the entities and contracts that support it also play a key role, including: - the EPC contractor, - the technology and battery suppliers, - the aggregator or route-to-market strategy, - the operator responsible for operations and maintenance (O&M), - and long-term agreements such as the LTSA (Long-Term Service Agreement), performance and availability warranties. Their track record, financial standing and the quality of the agreements concluded directly affect the project's operational stability, the predictability of revenues and the bank's credit risk assessment. In hybrid projects (e.g. BESS + RES) the importance of these elements is even greater, as they affect both the integration of technologies and the consistency of the revenue model.

Before the model is built — you need credible input assumptions

Every financial model is only as good as its inputs. That is why the assessment of bankability begins before any modelling. The key elements are: - market conditions and route-to-market, - the technical parameters of the storage system, including power, capacity, efficiency, degradation and number of cycles, - the operating strategy and the way the asset is run, - the contract structure, including LTSA, O&M, manufacturer warranties and agreements with the aggregator, - the quality of partners: EPC, battery supplier, aggregator, O&M operator, - regulatory and system assumptions, - and the battery manufacturer's warranty curve and how it is reflected in the model. The model must reflect not only the physics of the battery but also the warranty conditions, which in practice define the permissible operating profile, asset availability, the pace of degradation and the level of technological risk. In BESS projects, the manufacturer's warranty curve is not a technical detail but one of the key elements determining the project's revenue and risk profile. If these elements are weak, incomplete or inconsistent, even the best financial model will not be bankable.

First, you need to understand how much cash the project actually generates

A bank does not finance the abstract potential of a project but its ability to generate real cash flows. The key is to determine what share of revenues remains available after operating costs, taxes and maintenance spending such as replacement CAPEX, O&M or LTSA. The level of cash flows available is directly linked to the asset's degradation and to the constraints arising from the manufacturer's warranty. It is precisely this level that defines the project's actual debt service capacity.

Then you need to check whether the project will service the debt in every period

The level of cash flows alone is not enough. What matters is whether the project covers principal and interest with an adequate margin of safety — not only on average, but in every period of the loan. This is where real credit risk assessment begins.

The bank looks not only at the next year, but at the entire credit horizon

The project must be credible not only today but throughout the life of the debt. That is why the bank analyses future cash flows, their stability and their resilience to market, technology and operating volatility. The key question is: does the project maintain its credit capacity also under more difficult scenarios?

The level of debt must follow from the model, not from the sponsor's expectations

In a well-prepared project the level of financing is not arbitrary. It follows from how much debt the project is able to service safely under realistic asset operating, degradation and revenue volatility scenarios. Debt sizing is the result of the model, not of negotiation.

The financing structure must protect the bank under stress scenarios

Even a well-functioning project may temporarily generate lower cash flows. That is why the bank assesses not only the model but also the protective mechanisms built into the financing structure. The key elements are: - cash sweep, i.e. allocating cash flow surpluses to early debt repayment, - security accounts such as DSRA and other reserve accounts, - maintenance accounts and reserves for operating or replacement spending, - financial covenants, including a minimum DSCR, - and the waterfall structure, i.e. the order in which cash flows are distributed. It is precisely these mechanisms that determine whether the project will get through more difficult periods and whether the bank retains an adequate level of protection.

The quality of the model matters as much as the results themselves

Two models can show similar results but treat risk in entirely different ways. That is why banks compare the sponsor's model with an independent verification and analyse: - the quality of assumptions, - the consistency of the model's logic, - the way the asset's operation is reflected, - resilience to changes in parameters, - and consistency with contractual and technical conditions. This is where the difference arises between a presentation model and a bankable model.

Bankability is not an indicator — it is the result of the project's entire logic

It cannot be reduced to a single parameter. Bankability follows from: - the quality of the revenue stack, - the way the storage facility is operated and the dispatch strategy, - the resilience of scenarios, - the contract structure, including PPA, LTSA, O&M and manufacturer warranties, - the quality of the financial model, - the financing and security structure, - and the credibility of partners such as the EPC, battery supplier, aggregator and O&M operator. It is the result of the consistency of the entire project: technical, market, contractual and financial. Bankability does not follow from the financial model alone, but from the quality of assumptions, the project's operating logic and the structure of financing and security.

How Envalis sees it

At ENVALIS, bankability is not a layer added at the end of the model but the result of the project's entire logic. We start from the actual operation of the storage facility — its dispatch, technical constraints, degradation, warranty conditions and revenue structure. Only then do we translate these elements into CFADS, DSCR, debt level and security structure. As a result, the model is not merely a financial spreadsheet but a decision-making tool for the investor, the bank and the transaction adviser. Our approach combines the operational, market, contractual and credit perspectives, which makes it possible to judge whether the project is financeable in practice, and not only in a presentation.