OESTER: project to advance offshore electricity storage

Maximizing renewable energy utilization

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 utilization of renewable resources and limiting their potential to accelerate the energy transition.

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

Goal: scalable solutions

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 perspectives. The project’s ultimate goal is to deliver scalable solutions that can be applied across global markets, supporting the rapid deployment of renewable energy systems. 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 Storage (Ocean Grazer) co-located within wind farms
• Long-term storage: flexible pressurised alkaline electrolyser (flexolyser)installed on offshore platforms directly connected to wind farms (Battolyser Systems)

Preliminary Front-End Engineering Designs (FEED) and prototype components will be developed to validate these hybrid systems. Digital twins virtual representations of the hybrid system to reflect the physical operations accurately, will be employed to simulate system performance and optimize grid operations at gigawatt scale.

Next generation energy farms

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

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

The project has been approved under the framework of Mission-driven Research, Development and Innovation (MOOI), by the Netherlands Enterprise Agency.

Partners

Partners involved are:

• wind developers and operators: OranjeWind (wind farm from RWE and TotalEnergies), Vattenfall, and APG
• storage technology developers: Verlume, Flasc, Battolyser Systems and Ocean Grazer
• companies supporting offshore renewable energy and storage: DMEC and SeaWay7
• research and knowledge institutes supporting ecology, and digital twins of the system: Deltares and University of Groningen, and TNO (project coordinator)
• legal company New ground law