Power: Storage Becomes an Economic Factor – Vattenfall to Market New 285 MW Battery Portfolio

Berlin – Energy company Vattenfall is expanding its battery storage business in Germany. The company is taking over the marketing of four large-scale battery storage systems with a combined power capacity of 285 MW. The facilities are being developed by an independent flexibility provider at four sites in different German control zones. Vattenfall did not name the project developer.

Demand for storage is growing with the expansion of wind and solar power. The applications differ considerably, however, ranging from small storage systems that optimise self-consumption to large-scale storage marketed on the power market and grid-supporting storage that helps grid operators maintain stable and secure operations. Other technologies and use cases come into play for longer storage durations.

Vattenfall Takes Direct Control of Four Large-Scale Batteries Through 2036

According to Vattenfall, this is the first physical battery portfolio of its kind in Europe. Unlike virtually pooled battery storage, the company will gain direct control over the facilities and their operation.

The four battery systems are to be integrated into the company's automated trading and optimisation processes. Depending on market conditions, the storage systems will be deployed on both the wholesale power market and the balancing power markets. Owing to their fast response times, they can also offset frequency fluctuations and short-term imbalances in the power grid.

“With the growing share of renewable energy in the power system, flexibility is becoming increasingly important. Battery storage plays a central role in balancing generation and consumption and in making renewable power available when it is needed,” said Björn Schneegans, Head of the Origination Team and responsible for battery storage at Vattenfall.

Vattenfall did not disclose the storage capacity of the four facilities in MWh. The stated total power capacity of 285 MW therefore does not indicate how long the batteries can supply that power.

According to the company, all four projects have reached financial close. Three of the four storage systems are already under construction. Commercial commissioning is scheduled to begin from January 2027, depending on the completion date of each project. The agreements governing Vattenfall's use of the storage systems run until 2036.

Vattenfall plans to optimise a battery portfolio with a total power capacity of 1.5 GW in the coming years. In parallel, the company is building its own storage capacity. According to the company, around 270 MW are already in operation or under construction. In addition, there are a further 254 MW at the Brunsbüttel site, according to the company.

Not All Storage Is Alike – Different Roles in the Power System

Battery storage can serve very different functions in the power system. Smaller systems at households or businesses are often used to store self-generated solar power temporarily and thereby increase self-consumption. Large-scale battery storage such as the facilities marketed by Vattenfall, by contrast, mainly follows a market-based business model. Their flexibility is marketed on various power markets and optimised depending on prices and market conditions.

Another application is the targeted use of storage for grid support. Here, the focus is not primarily on exploiting price differences on the power market, but on supporting stable and secure grid operations.

Grid operators are responsible for secure grid operations. They can determine what storage capacity their grid requires and which technical requirements must be met, and can tender for and procure corresponding storage and flexibility services on the market. Owing to their monopoly position in grid operations, however, they are generally not allowed to own or operate storage themselves; this is only possible in approved exceptional cases. One example of such an exception is the grid booster of transmission system operator TransnetBW in Kupferzell, with a power capacity of 250 MW and a storage capacity of 250 MWh.

The different fields of application are not strictly separate, however. A battery storage system can technically perform several functions.

Long-Duration Storage: From Redox Flow to Hydrogen – Storage Duration Determines Technology

Longer storage durations are a separate matter. Other battery technologies can also become relevant here. A current example is the FlexBase project in Laufenburg, Switzerland, where a vanadium redox flow battery with an initial storage capacity of up to 1.5 GWh is planned. Grid connection capacity is limited to a maximum of 800 MW in the first project phase. How long the stored energy lasts, however, depends on the power actually drawn: the lower the power, the longer the storage system can supply energy. In a later expansion stage, storage capacity is to rise to up to 2.1 GWh, according to technology provider Invinity.

The example shows why, alongside power capacity in MW, storage capacity in MWh or GWh is a key parameter for storage systems. Power capacity determines how much electricity can be supplied at a given moment, while storage capacity determines how much energy is stored in total. Because power and storage capacity can be scaled separately, redox flow batteries are particularly of interest for longer storage durations.

Other storage solutions come to the fore for bridging even longer periods of days, weeks or seasonal fluctuations. These include hydrogen in particular, but also compressed air, thermal and other long-duration storage. Which technology is suitable depends largely on the required storage duration and the specific area of application.

Source: IWR Online, 08 Oct 2026