New European Project to Tackle Offshore Energy Storage Challenges

February 13, 2025, by Adnan Memija

Sixteen partners from across the European offshore renewable energy sector have launched the Offshore Electricity Storage Technology Research (OESTER) project to accelerate the development of offshore electricity storage.

Several major energy industry players, such as RWE, Vattenfall, and the Dutch research organisation TNO, are part of this three-year initiative, which aims to accelerate the development and deployment of offshore electricity storage technologies.

Approved under the framework of Mission-driven Research, Development and Innovation (MOOI), by the Netherlands Enterprise Agency (RVO), the project addresses challenges in the renewable energy transition, such as system integration, and demonstrates the benefits of adopting this technology, said the Dutch Marine Energy Centre (DMEC).

As renewable energy systems expand, they face challenges like grid congestion and system instability caused by the mismatch between variable energy production and demand. These issues often result in electricity curtailment, reducing the effective utilisation of renewable resources and limiting their potential to accelerate the energy transition, according to the press release.

Additionally, simultaneous electricity production from multiple wind farms can lead to oversupply, causing electricity prices to plummet, which impacts the business case of offshore wind farms. Energy storage systems could offer a viable solution to these challenges.

The core mission of the OESTER project is to mature, de-risk, and validate innovative offshore electricity storage solutions from technological, economic, environmental, and societal aspects.

Key technologies under evaluation include: short-term storage – batteries integrated into wind turbine monopiles (Verlume); medium-term storage – compressed air energy storage (Flasc) and underground pumped hydro (Ocean Grazer) co-located within wind farms; long-term storage – electrolyser system installed on offshore platforms directly connected to wind farms (Battolyser).

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Preliminary Front-End Engineering Designs (FEED) and digital twin simulations could optimise system performance at a gigawatt scale.

By integrating storage systems into offshore wind farms, the OESTER project supports the development of next-generation offshore wind farms into advanced, multi-faceted energy hubs combining wind, energy storage, and potentially other renewable technologies.

These integrated energy farms are designed to provide baseload energy, enhancing system reliability and flexibility from the supply side, said DMEC.

In addition to RWE and Vattenfall, other developers and operators include SSE and APG. Verlume, Flasc, Battolyser Systems, Ocean Grazer, DMEC, and SeaWay7 are also participating.

Other research organisations in the project include Deltares and the University of Groningen. Legal Company New Ground Law and Energy Storage NL are also involved.