Vattenfall has taken a final investment decision to construct one of Germany's largest battery storage facilities at its Brunsbüttel site, the Swedish energy company announced on 10 September 2026.

The project, with an output of 254 MW and a storage capacity of around 1,000 MWh, will be built on the grounds of the former Brunsbüttel nuclear power plant, which is currently undergoing decommissioning.

A Landmark Project for Vattenfall's Battery Portfolio

The Brunsbüttel installation represents Vattenfall's largest battery energy storage project to date. Once operational, it will nearly double the company's existing battery capacity. Vattenfall's current portfolio stands at 150 MW in operation and a further 120 MW under construction, the majority of which is co-located with wind and solar projects.

The Brunsbüttel facility, by contrast, will be a standalone battery, connecting directly to the 50 Hertz 380 kV transmission grid. Commissioning is expected by the end of 2028.

Claus Wattendrup, Head of Solar and Batteries at Vattenfall, described the decision as significant for the wider region. "This is excellent news for Brunsbüttel as an energy hub, and we are excited to move forward with this project," he said.

"Batteries play a key role in the future energy system, balancing electricity demand and supply. As generation from solar and wind power continues to grow, powerful storage solutions are essential for strengthening energy security and reducing dependence on fossil fuel imports."

Repurposing a Nuclear Decommissioning Site

The choice of location carries symbolic weight as well as practical logic. The Brunsbüttel nuclear power plant is currently being decommissioned, and the battery project will make use of the existing site infrastructure as Germany continues its broader shift away from nuclear and fossil fuel generation toward renewables. The grid connection will run directly into the 50 Hertz 380 kV transmission system, providing direct access to Germany's high-voltage network.

The project reflects a pattern emerging across the European energy sector, in which sites previously associated with conventional generation are being repurposed to support the infrastructure demands of the energy transition. Vattenfall has not provided further details on how the existing site facilities may be used in the construction or operation of the battery.

Germany's Rapidly Growing Demand for Storage

The investment comes against a backdrop of rapidly rising demand for large-scale battery storage across Germany. The country's transmission system operators expect large-scale battery storage capacity to exceed 80 GW by 2040, driven by the need to integrate growing volumes of solar and wind electricity into the grid and to maintain stability as variable renewable generation accounts for a rising share of supply.

Battery storage allows grid operators and energy companies to absorb surplus electricity during periods of high renewable output and release it when generation falls short of demand.

As solar and wind capacity continues to expand across Germany and the broader European market, the ability to store and dispatch electricity flexibly is becoming an increasingly critical element of grid management.

Vattenfall's Broader Flexibility Strategy

The Brunsbüttel project is described by Vattenfall as a central element of its wider flexibility strategy. Beyond building and operating its own battery assets, the company is actively expanding a third-party optimisation business, in which it manages and markets battery capacity on behalf of external asset owners.

By 2029, Vattenfall aims to optimise a battery portfolio of up to 1,500 MW through this service. The company has framed the combination of owned assets and optimisation services as a means of integrating greater volumes of renewable electricity into the grid while supporting what it describes as a more flexible, reliable and affordable energy system.

The existing 150 MW of battery capacity already in operation, alongside the 120 MW under construction, forms the foundation of this portfolio. The Brunsbüttel addition will significantly increase Vattenfall's owned capacity, reinforcing its position in the German and broader European storage market at a time when competition for battery development sites and grid connection capacity is intensifying.

Battery Storage as Critical Infrastructure

Vattenfall's announcement frames the Brunsbüttel project not simply as an individual commercial investment but as part of a structural shift in how energy systems are built and managed.

The company stated that batteries are becoming a critical part of the infrastructure that enables the energy transition, a characterisation that reflects growing recognition among grid operators, regulators and energy companies that storage is no longer a peripheral technology but a foundational component of modern electricity systems.

The project's scale, at 254 MW of output and up to 1,000 MWh of storage capacity, places it among the most significant battery installations in Germany. Its connection to the 50 Hertz transmission grid rather than at the distribution level underlines its intended role in system-level balancing rather than localised energy management.

Vattenfall has not disclosed the total capital investment associated with the Brunsbüttel project or detailed the commercial arrangements underpinning its revenue model for the facility.

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