Bankability by Design: Bankability by Design: What Makes a Battery Energy Storage Project Bankable?
- Pia Armbruster
- 3 days ago
- 3 min read
A Whitepaper by suena energy and Capcora
Battery energy storage systems (BESS) are becoming an increasingly critical part of Germany's power infrastructure. They enable the temporal shifting of energy, support grid stability, and enhance the marketability of intermittent renewable generation from wind and solar. Their role in the energy system is undisputed, and investor interest continues to grow accordingly.
Yet available capital alone does not translate into new projects. Between investor appetite and a financed asset lies a question that is often underestimated in practice: What makes a BESS project bankable?
Lenders Think Differently Than Developers
Developers typically focus on revenue potential: day-ahead (DA) arbitrage, ancillary services, and intraday trading. Their base-case assumptions are optimistic, the technology is proven, and the project location is attractive.
Lenders take a fundamentally different perspective. Their primary concern is not the base case, but the downside case: Can the project continue to service its debt if market prices decline, cycling decreases, or the regulatory environment changes?
This difference in perspective forms the foundation of our joint whitepaper with Capcora, a boutique advisory firm specializing in financing the energy transition.
Capcora contributes its expertise in debt financing and credit assessment, while suena energy provides the perspective of commercial optimization and revenue generation strategies.
Four Evaluation Dimensions: Why They Must Be Considered Together
Bankability is not determined by a single factor. It results from the interaction of four key evaluation dimensions that lenders use to assess battery energy storage projects.
Technical fundamentals form the basis of cash flow modelling. Lenders are less concerned with a battery's technical performance than with what is contractually guaranteed and remains reliable over the asset's lifetime, including availability guarantees, degradation profiles, and the creditworthiness of the equipment manufacturer. Unclear responsibilities between the EPC contractor and the operations provider, for example who is liable if guaranteed system availability is not achieved, lead directly to more conservative risk assumptions in the financing model.
The regulatory and market framework determines whether a battery can translate its operational flexibility into financeable cash flows. Grid connection requirements, prequalification criteria, and the stability of market regulations throughout the project lifetime are not secondary considerations. Uncertainties, for example regarding grid fees beyond 2029, are immediately reflected in more conservative scenarios and more extensive sensitivity analyses.
Project economics represent the most significant evaluation dimension. In market-based revenue models, there is no long-term contracted off-taker of the kind typically found in traditional infrastructure financing. Instead, lenders must assess market price exposure and merchant risks, which have structural financing implications, including shorter debt tenors, more conservative repayment profiles (sculpting), and lower leverage.
Commercial models provide the critical link between market dynamics and project financing. They determine how effectively market opportunities can be converted into bankable and financeable cash flows.
The whitepaper analyzes five commercial models currently used in the market:
Fully Merchant: All revenues are generated through energy trading and ancillary service markets, offering maximum upside potential but limited bankability.
Floor Model: A contractually secured minimum revenue level provides an initial degree of revenue certainty and moderately improves bankability.
Day-Ahead Swap (FlexFloor): A financial settlement mechanism based on the EPEX Spot Day-Ahead market that guarantees a fixed price while allowing full participation in physical market revenues.
Partial Tolling: A defined share of the battery's capacity is remunerated under a fixed contract, while the remaining capacity is commercially optimized based on market conditions.
Full Tolling: The entire battery capacity is contracted under a fixed remuneration scheme, offering maximum revenue certainty and the highest level of bankability while limiting upside potential.
As revenue certainty increases, so does debt financing capacity, while upside potential declines. This trade-off cannot simply be engineered away. It is a fundamental strategic decision that every project must address.
Hybrid structures such as the Day-Ahead Swap demonstrate that this decision does not have to be an either-or choice. They provide the bankable revenue floor required by lenders, while preserving sufficient exposure to market opportunities and upside potential.
Early Decisions Shape Bankability
For project developers, this leads to a clear conclusion: the commercialization strategy, risk allocation, and revenue structure are not downstream financing considerations. They are integral elements of project structuring and should therefore be addressed from the earliest stages of development.
Developers who understand how lenders assess projects and structure their assets accordingly from the outset create the conditions for successful project financing. Rather than being a constraint, bankability becomes a strategic advantage.
The full whitepaper, "Bankability by Design: Financing and Commercial Models for Battery Energy Storage Projects," including a detailed discussion of all four evaluation dimensions, the complete case study, and expert commentary on the current equity investment market for battery energy storage, is available for download here:
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