Why the strategy is key: Lessons from real-world benchmarks

While the case for batteries as enablers of flexibility is widely accepted, the path to profitability remains far from settled. As more projects enter the pipeline, competition is intensifying, placing growing pressure on operators to extract value from volatile market conditions.  In this increasingly more complex market landscape, the ability to generate stable returns is no longer a given, but the product of strategic precision and operational excellence.

Flexibility as a challenge

This is especially true for standalone battery storage systems. Like fully merchant colocated assets, they are fully exposed to market prices and system signals. What distinguishes standalone systems, however, is their operational autonomy: they are grid-connected but not dependent on wind or solar plants. This allows them to participate freely across energy and ancillary service markets.

In theory, this autonomy allows for maximum flexibility. In practice, it demands constant re-evaluation of trading priorities, regulatory rules, and asset constraint, such as degradation, state of charge (SoC) limits, and ramping profiles. Each day presents a different set of variables: auction timings, capacity pricing, intraday spreads, and redispatch signals all evolve dynamically – and frequently in conflict with one another.

The case for multi-market strategies

In this context, profitability becomes a matter of coordination across markets. A standalone battery isn’t simply buying low and selling high – it’s navigating a complex, overlapping mix of opportunities and trade-offs. Wholesale markets like day-ahead (DAM), intraday auctions (IDM), and continuous trading (IDC) offer arbitrage windows that shift hourly. Balancing services such as FCR and aFRR run on their own timetables and merit orders.

The most viable and resilient strategies today treat these markets as a portfolio, dynamically stacking revenues while managing risk. This means deciding, in real time, how much capacity to allocate to each market, and adjusting to failed bids or changing prices on the fly.  Achieving this in practice requires intelligent automation – systems that can evaluate market conditions, optimize dispatch decisions, and reallocate capacity within minutes.

We at suena, for example, have developed the suena Energy Trading Autopilot that models multi-market trading strategies at 15-minute intervals, and continuously reallocates battery capacity between services like FCR, aFRR, and wholesale markets. If an FCR bid is unsuccessful, capacity is instantly redirected to wholesale trading. aFRR bids are adjusted just before delivery based on updated forecasts. All the while, the autopilot accounts for roundtrip efficiency, degradation, and contractual limits – executing a real-time multi-market strategy not just optimized for return, but also for reliability and operational safety.

Benchmarking the opportunity

The benefits of such coordinated and dynamic, multi-market optimization are also clearly reflected in revenue simulations, such as our monthly revenue update. This simulation-based benchmark evaluates what a well-optimized stand-alone BESS could have earned using real market data, forecast and operational logic. Each month, we model a standardized 10 MW / 20 MWh battery with realistic assumptions: no perfect foresight, 90% roundtrip efficiency, and compliance with market rules and bid structures.

Rather than estimating theoretical upside, the update tests actual market strategies: single-market arbitrage, FCR-only, aFRR-only, and fully integrated approaches. Dispatch decisions use market forecasts, while revenues are settled at actual prices, mirroring how trading would perform in a real-time operational environment. This methodology allows us to examine, under market-compliant conditions, how various strategies perform: whether single-market arbitrage, aFRR capacity bids, FCR-only routes, or dynamically stacked combinations. What emerges is not a hypothetical earnings range, but a practical benchmark for what a commercial standalone battery could have captured – if operated with full market access and strategic agility.

What these monthly snapshots reveal is both intuitive and striking: in virtually every month we’ve modelled, multi-market optimization outperforms isolated strategies by a significant margin. In May 2025, for instance, the suena Energy Trading Autopilot delivered €31.5k/MW, the highest monthly earnings since June 2024. By combining aFRR charging and opportunistic spot market discharges, the strategy outperformed the spot market benchmark by 80%, aFRR capacity services by up to 78%, FCR by 100%, and single spot market optimisers by as much as 236%. The upward trend continued into June, where our simulations showed another record with €31.6k per MW in revenue, exceeding the spot market benchmark by 45%, FCR by 171%, and single spot markets by even up to 253%.

Simulations, of course, have limits. No benchmark can fully reflect the variability of real asset behavior, redispatch exposure, or maintenance windows. Regulatory shifts, local grid charges, or unforeseen market behavior can all shift the playing field in ways that models may not anticipate. However, they help operators and investors identify underperformance and shifting market dynamics, as well as aligning expectations with reality.

Operational intelligence as the defining capability

These findings do not suggest that any of these markets has lost relevance. Rather, they underscore the volatility and interdependence of all value streams. No static strategy can consistently deliver superior results. The implication is clear: storage profitability hinges on dynamic, adaptive optimization – the ability to continuously reallocate, re-prioritize, and respond to price signals across all relevant timeframes. This is precisely why real-time automated trading is becoming the defining capability of profitable storage operations. Optimizers are not optional add-ons, but foundational tools – that enable sustainable returns.

In a landscape characterized by commercial risk, regulatory uncertainty and growing competition, these systems enable stand-alone battery energy storage systems to evolve from technical assets into strategic operators and, ultimately, viable long-term investments.

About the author:

Dr Lennard Wilkening is co-founder & CEO of suena energy, a green energy marketer for battery storage and renewables. suena offers marketing solutions that enable profit-maximizing multi-market trading and implement them through powerful trading algorithms. Lennard holds a PhD in grid-oriented use of battery storage systems from the Technical University of Hamburg and has more than nine years of experience in battery storage optimization and energy trading.