Revenue Stacking for BESS: How Multi-Market Optimisation Maximises Battery Storage Returns

A recurring pattern can be observed across all mature battery storage markets: as installed capacity of Battery Energy Storage Systems (BESS) grows, achievable revenues from ancillary services decline due to market saturation. What starts out as a highly attractive market gradually evolves into a fiercely competitive arena with shrinking margins.

For asset owners, this means that a revenue model centered on a single market is simply not sustainable. Instead, BESS must leverage their inherent flexibility to tap into multiple revenue streams simultaneously.

This is precisely where revenue stacking comes in. In this article, we explain what it entails, how a multi-market strategy works in practice, and how the revenue potential for BESS is likely to develop in the years ahead.

Revenue stacking means an asset — in our case a BESS — generates income from multiple sources rather than just one. Instead of operating the storage asset exclusively in the ancillary services market, different markets are utilised in parallel: day-ahead, intraday, grid services, or capacity mechanisms.

The rationale is economic: every market is attractive at different points in time. If your battery storage system always participates in whichever market offers the greatest revenue opportunity at any given moment, you can maximise your overall returns.

When implemented correctly, revenue stacking delivers a higher total return, a shorter payback period, and better asset utilisation. As an asset owner, you also become less dependent on individual, potentially volatile revenue sources.

Battery storage systems possess a number of technical characteristics that make them particularly well-suited for revenue stacking across energy markets:

• Fast response times: BESS can respond within milliseconds, giving them access to high-value, short-duration markets where speed is directly monetised.
• High operational flexibility: Without rigid minimum run times, battery storage systems can adjust their dispatch profile at any time and selectively exploit price differentials between markets.
• Efficient capacity utilisation: Grid services only draw on the battery for brief periods, leaving a large share of capacity available for parallel or sequential deployment in other markets.
• High precision and controllability: This enables exact dispatch in line with market requirements and forms the foundation for algorithmic optimisation across multiple markets.

BESS are not the only assets capable of participating in several markets simultaneously. However, their combination of flexibility, speed, and controllability makes them especially well-suited for revenue stacking.

The revenue logic for battery storage systems has fundamentally shifted over the years. In the early days, BESS were deployed almost exclusively for primary frequency response, as that market aligned perfectly with their technical capabilities. With little competition, they were able to command high prices.

As installed storage capacity grew, however, a structural saturation effect set in. In Germany, this became apparent from around 2016 onwards: falling prices and limited activation volumes forced operators to seek additional revenue sources in order to maintain the economic viability of their assets.

This saturation effect has been observed in every mature market, including:

• Belgium: The aFRR capacity remuneration for upward regulation collapsed from €70/MW/h to below €11/MW/h within just a few months as new BESS capacity entered the market. Annual revenues fell from approximately €750,000/MW in Q2/Q3 2024 to around €200,000/MW at the start of 2025 — a decline of over 70% in less than two quarters.
• Great Britain: While frequency response accounted for 80% of BESS revenues in 2022, a near-tripling of installed capacity by 2024 forced a fundamental reorientation of trading strategies.

These examples make two things clear:

• Single markets are not stable revenue sources. They can shift from attractive to unviable within just a few quarters.
• At the same time, new short-term market opportunities can emerge just as quickly.

Revenue stacking is therefore no longer an optional optimisation strategy — it is a prerequisite for economically viable operation.

Simply participating in multiple markets does not, in itself, automatically lead to higher revenues. The decisive factor is the ability to allocate available capacity across markets in real time.

Historically, operators often relied on static capacity allocation: fixed portions of a battery storage system were assigned to individual markets, such as primary frequency response or the spot market. While this approach offered a degree of planning certainty, it overlooked a critical variable: opportunity costs. In an increasingly volatile and competitive market environment, this leads to assets being systematically locked into less attractive markets.

To truly maximise total revenues, what matters is how quickly and precisely the dispatch strategy can be adapted to changing market conditions.

This is where the multi-market strategy comes into play. Rather than being statically assigned to a single product, the asset is dynamically allocated across day-ahead, intraday, and ancillary services markets — always directed towards the highest risk-adjusted return available at any given moment.

The critical factor is not market participation per se, but the ability to continuously adapt the allocation logic to evolving market conditions.

Implementing a multi-market strategy (also referred to as a cross-market strategy) is operationally and technically highly complex. At every point in time, decisions must be made about how to allocate available capacity across different markets — taking into account prices, forecasts, opportunity costs, and technical constraints.

In practice, multi-market optimisation is only achievable through a fully automated, AI-driven optimisation algorithm. The sheer number of influencing variables, divergent market mechanics, and the required decision-making frequency make manual management structurally impossible.

This is where the difference between an average and a truly high-performing BESS optimiser becomes apparent — one that seamlessly integrates technology, data, and market expertise. Because it is not simply about serving multiple markets in parallel; it is about consistently making the economically optimal decision in a dynamic environment.

The algorithm alone is not sufficient. What matters is the combination of algorithmic sophistication, data quality, and market intelligence. Ongoing analysis of market mechanics and regulatory developments enables early anticipation of changes and timely adjustment of the optimisation logic.

At The Mobility House Energy, this feeds directly into the parameters of our trading algorithm and our strategic allocation logic. This allows us to identify saturation effects early and stay structurally ahead of them.

The growing demand for precisely this form of optimisation is reflected in our own growth: in the first quarter of 2026, we expanded our managed portfolio by 235 MW/630 MWh of battery storage capacity.

The European BESS market continues to grow at a rapid pace. In Germany alone, more than 5 GWh of large-scale battery storage is already installed, with the trajectory clearly pointing upwards.

With this growth, however, the demands on asset commercialisation are also intensifying:

• Ancillary services markets are facing structural price pressure: FCR and aFRR require capacity reserves that generate opportunity costs in spot and intraday trading. In an environment of declining ancillary service prices, provision only remains worthwhile if these opportunity costs are dynamically and realistically weighed against spot market returns.
• Algorithmic capability becomes the central differentiator: When all market participants are trading the same products, it is no longer market access that determines outcomes — it is the quality of optimisation. Those who analyse market microstructure more precisely, react faster, and price in cycle costs more accurately will achieve superior returns.
• Cross-border strategies are gaining strategic importance: As Germany, France, and Belgium increasingly converge through PICASSO (the European platform for coordinating and activating balancing energy) and price differentials equalise, new and attractive markets are emerging in Poland, South-Eastern Europe, and the Balkan region — markets with low competitive density and significant growth potential.

In parallel, grid-serving operation of battery storage systems will become increasingly important. Transmission and distribution system operators are under growing pressure to manage grid congestion, maintain frequency stability, and avoid costly redispatch measures. Battery storage systems located at the right grid nodes can provide meaningful support in this regard.

For asset owners, this creates additional revenue potential that goes beyond pure market optimisation. The next evolutionary stage for battery storage therefore lies in the intelligent integration of multi-market strategies and grid-serving operation through flexible connection agreements (FCAs).