When determining the value of BESS assets and how much revenue they can generate, we encounter several assessment methods. Portfolio performance shows real revenues achieved by enspired for 1-3.5-hour storages in Germany, confirmed by an independent third party for full transparency. A bankable forecast, on the other hand, is a longer-term, model-driven perspective of revenue potential based on current market conditions, future buildout, and regulatory impacts. Bankable forecasts are typically updated biannually and used to obtain project financing from banks. Part of an optimizer’s job is to generate revenues that can secure this financing. So far, the market and industry have been missing the correlation between bankable forecasts and real-world BESS (battery energy storage system) revenues. Insight into actual asset performance helps bankable forecast providers validate the accuracy of their revenue projections, and enspired adds this crucial information to the equation.
In times of complex market conditions and grid constraints like in Germany, trustworthy revenue information is essential for planning a BESS project. Many factors influence the commercial performance of battery systems, including flexible connection agreements and different co-location setups. Backtests, retrospective analyses of how an asset could have performed based on historical data, can be useful for indicating future revenue potential, but they’re also susceptible to manipulation, as low-revenue periods can be excluded to artificially inflate performance. This means that reliable insights can only come from live assets and real revenues, confirmed by an independent auditor.
From live-optimizing batteries of varying configurations across nine countries in Europe in a cross-market setup, we know what makes a project financeable. As a stakeholder in the asset value chain, we advise customers on financing and have successfully implemented BESS projects with many different banks, including:
Those who seek financing for their BESS project need to know how much revenue they can expect and where this revenue is coming from. Tolls offer the highest contracted revenue, meaning revenue that is guaranteed regardless of commercial performance. The ideal revenue model always depends on the gearing levels you want or need to achieve for your project; in other words, how much of the project can be financed with equity and how much must be financed with debt. For tolled projects, financing structures entail higher debt because there’s no exposure to risk (it transfers to the optimizer), whereas fully merchant projects require higher equity. Upside potential in tolling applies only to partial tolls (e.g., 80% tolled and 20% merchant), as the upside in this setup comes from the merchant part. For fully merchant cases, the upside potential is, in principle, infinite. The general rule of thumb here is that the upside grows with the merchant share, regardless of the revenue model.
The difference between a physical toll and a financial toll lies in asset control and responsibility. In a physical toll, the offtaker rents the asset from the owner for a fixed amount. This setup grants the offtaker operational and commercial control over the asset. In a financial toll, the owner stays in control, while the offtaker leverages arbitrage opportunities in exchange for a fixed fee. The achievable gearing level of a project doesn’t depend on the toll type (physical vs. financial), but on the amount and duration of the toll.
Day-ahead (DA) swaps are financial, non-physical products that exchange the floating daily price spread (difference between the highest and lowest DA hourly prices) for a fixed cash flow. Due to their predictability, they can be an attractive option for asset owners seeking to stabilize revenues and improve bankability. DA swaps may be sufficient to receive project financing, but since they’re speculative products and fully decoupled from battery dispatch, banks typically accept them in a complementary function to contracted revenues, not as a replacement. This additional security typically comes in the form of a hybrid structure, entailing, for example, 50% tolling, 30% DA swap, and 20% fully merchant revenue components.
For floors, the situation is similar to DA swaps: Contracted revenues and gearing levels are on the lower end, but the upside potential is higher than for tolls. As a bankable optimizer with a comprehensive partner network, enspired acts as a key enabler of project financing for all use cases and revenue models.
The graph below shows predicted weather ranges and BESS revenue forecasts by AFRY. The central projection aligns closely with enspired’s average portfolio performance, indicating clear achievability even in a year like 2025, which saw a seasonally uncharacteristic July with low revenues in Germany. The high case partially overlaps with portfolio performance, but this projection assumes perfect foresight and market conditions.
Without a bankable optimizer, BESS projects face difficulties in obtaining financing and could end up with higher financing costs. As partners in bankability, enspired (bankable optimizer) and AFRY (bankable forecast provider) solve this challenge by providing a comprehensive bankable setup that optimally serves lender expectations and makes project financing easier for BESS owners. One key aspect of our bankability is transparency across assumptions, revenues, and risks, which facilitates the evaluation of financing structures. Complemented by a strong network of partner banks and credit institutions, this strategy helps you secure optimal financing conditions for your BESS project.