By James Dunlop, Director of Investor Relations
S4 Energy
19th March 2026
When we look back at 2026, it may well be remembered as the year battery energy storage systems (BESS) truly reached scale in Europe. That sense was unmistakable at the Energy Storage Summit 2026 in London earlier this year. Across panels, investor meetings and industry discussions, one message came through clearly: battery storage is moving from promise to infrastructure.
But optimism alone will not build projects. To seize the moment, developers and operators must capitalize on three shifts now reshaping the sector: maturing revenue models, falling system costs and a new level of scrutiny from investors. Together, they are turning BESS into one of the most compelling investment opportunities in the energy transition.
Revenue models are finally diversifying
For years, battery projects relied heavily on a narrow set of services, particularly frequency response markets. As these markets matured, and in some cases saturated, the industry faced legitimate questions about the long-term business case.
What we are now seeing is a broader and more resilient revenue stack emerging. Markets for capacity, energy arbitrage and tolling are deepening, particularly in the UK, rebuilding the commercial logic for storage projects. Across Europe, new frameworks are also taking shape. Ukraine, for example, is rebuilding critical aFRR reserves through battery capacity auctions despite the immense pressures on its energy system.
The direction of travel is clear: BESS revenues are becoming more diversified and more market-based. Projects increasingly rely on multiple revenue streams across services, durations and geographies. That diversification is strengthening the investment case for battery storage across Europe.
Costs are falling but execution matters
At the same time, the cost dynamics of battery storage are shifting dramatically. Much attention has been paid to lithium price volatility. But zoom out and the picture looks very different. Lithium prices remain well below their peak in 2022, and the broader cost curve for storage systems continues to move downward.
According to Bloomberg research, turnkey EPC costs for battery storage projects in Europe fell by roughly 37% in 2025. That decline is accelerating the scale and pace of deployment across the continent. But falling costs alone do not guarantee successful projects. In fact, the same research shows that project costs can vary by as much as threefold between best- and worst-in-class procurement strategies.
In other words, expertise matters. Procurement, supplier relationships and project execution increasingly determine whether developers capture the benefits of these declining costs.
The learning curve of the technology is only part of the story. The quality of project delivery is becoming the decisive factor.
Investors are backing teams, not just technology
The third theme emerging from the summit was investor sentiment. There is little doubt that battery storage is currently one of the hottest segments within renewable energy. BESS is rapidly becoming the flexibility backbone needed to unlock further wind and solar deployment.Investor appetite reflects that reality.
But the market is also becoming more discerning. The slowdown in some M&A activity is not due to a lack of interest. Rather, investors are becoming more rigorous in assessing project quality and delivery risk.
As battery projects scale from tens to hundreds of megawatts, complexity multiplies. Grid access, procurement strategies and operational expertise all become critical. One phrase repeated during the summit captured the shift perfectly: execution, not equipment, is the key risk and the main source of delays.
Investors are not just backing hardware anymore. They are backing teams, their experience, credibility and ability to deliver projects in increasingly complex markets.
2026 will separate paper projects from real ones
Despite the strong momentum, challenges remain. Grid congestion continues to slow deployment in several markets, particularly in the Netherlands and Germany. At the same time, increasing competition will inevitably put pressure on some revenue streams as more storage capacity comes online.
Perhaps most importantly, the enormous pipeline of announced projects across Europe will soon face a reality check. Many battery projects exist on paper. Far fewer are ready to build. That is why 2026 may become the year that separates credible, deliverable projects from the rest. Some projects will move forward, others will stall, and many will seek experienced partners capable of bringing them to execution.
In a rapidly scaling industry, track record matters. Battery storage is no longer an emerging technology. It is becoming critical infrastructure for Europe’s energy transition. For developers able to combine diversified revenues, disciplined procurement and strong execution, the outlook remains exceptionally bright.
