SUNOTEC’s Stendal battery storage project enters construction phase

The Stendal battery storage project, a 100MW/441MWh standalone battery energy storage system (BESS) in Saxony-Anhalt, has moved into construction, with SUNOTEC acting as full-turnkey provider covering engineering, installation, and long-term operations and maintenance.

The project reached Ready-to-Build status in the second quarter of 2026, and commissioning is planned for Q1 2027. Upon completion, the facility is expected to rank among Germany’s largest battery storage systems, a market SUNOTEC describes as an expansion of its existing European activities.

What the Stendal battery storage project actually does

The system’s stated function is grid flexibility: storing electricity when supply is high and releasing it when demand requires it. In a German energy market where wind and solar generation can swing sharply, that kind of dispatchable storage has real operational value. The Stendal project is not attached to a generation asset; it is a standalone system, which means its commercial viability depends on revenue from grid services and wholesale arbitrage rather than a captive power source.

SUNOTEC claims 6.1GWh of BESS capacity installed across Europe to date. Bernhard Suchland, CEO of SUNOTEC, put it plainly: ‘We have spent the past years building battery storage at a scale that would have seemed ambitious not long ago. Today, SUNOTEC has installed over 6 GWh across Europe. What we have learned there is simple: storage works, and Europe needs much more of it.’

That track record is worth noting in a sector where developer claims frequently outpace delivered capacity. A portfolio measured in gigawatt-hours, rather than gigawatts of pipeline, is a more grounded metric, though the company has not, in this announcement, broken down how that 6.1GWh is distributed across projects or geographies.

The joint venture and grid connection behind the build

The project was developed to Ready-to-Build status within SECURSUN, the joint venture between SUNOTEC and securenergy. SUNOTEC is leading delivery as implementation begins, with the JV structure suggesting a division of roles between development and construction execution.

Grid connection is being handled separately. WT Energiesysteme GmbH is constructing a new 110kV substation at the Stendal site to provide the infrastructure needed to connect the battery system to the transmission network. That is a non-trivial piece of civil and electrical engineering, and its inclusion in the announcement signals that the project is not simply dropping a battery onto an existing connection point. A dedicated 110kV substation suggests the system is sized to interact directly with high-voltage grid infrastructure, which is consistent with its intended role in frequency response and balancing services.

Grid connection timelines are frequently the variable that slips in large-scale BESS projects across Europe, so the commissioning target of Q1 2027 will depend in part on WT Energiesysteme GmbH delivering the substation on schedule alongside SUNOTEC’s own installation programme.

Germany as a strategic market

SUNOTEC describes Germany as a new market for its battery storage activities, which raises an obvious question: why now? Germany’s grid has been under increasing pressure as coal and nuclear generation has exited the system, and the country has been slower than the UK or some Nordic markets to build large-scale standalone BESS capacity. A 441MWh project in Saxony-Anhalt, if it delivers on its timeline, would be a meaningful addition to German storage capacity rather than a rounding error.

The Stendal project’s Q1 2027 commissioning target is the clearest near-term test of SUNOTEC’s claims. If the substation is energised and the BESS is operational on schedule, the company will have something concrete to point to as it pitches further projects in the German market.