StEnSEA 2.0

StEnSEA 2.0 - Stored Energy in the Sea

Following the successful 1:10 scale model test at a depth of 100 m in Lake Constance in the first StEnSea project, the follow-up project aims to demonstrate that the technology can also be successfully applied at larger scales and greater depths. A detailed description of operation principle and further information can be found on the StEnSea topic page.

As part of StEnSea 2.0, a 1:3 scale functional model is planned to be realized off the California coast, as the next essential development step, and tested in the sea at a depth of approximately 650 m over a period of about one year. The final definition of the dimensions of the functional model is part of the project, depending on a variety of factors such as available logistics solutions. The goal of the project is to achieve a storage capacity of approximately 0.5 - 1 MWh and power output of 0.5 - 1 MW with the 1:3-scaled StEnSea system. This grid-relevant size enables integration into distribution networks, allowing even the prototype to be used in relevant applications for industry or for local grid relief.

© sperra
Potential sites off the coast of Los Angeles, California

1314130077 — © sperra
Principle of manufacturing the 10m sphere using 3D printing

In this second research project, two parallel projects are being funded. In the German project, Fraunhofer IEE and its project partner Pleuger Industries GmbH are developing the technical unit, whose main components include the pump turbine and the measurement, control, and regulation systems. In the U.S. project, the company Sperra is developing and manufacturing the concrete sphere using a novel 3D concrete printing process.

Funding follows the Berlin model, whereby each national partner is funded by its respective national funding agency and the offshore test is ultimately conducted jointly in the U.S. off the California coast. As part of the collaboration, the U.S. project partner Sperra coordinates the offshore test on the American side. In addition to obtaining permits from local grid operators and the relevant authorities, this includes detailed geotechnical investigation of the site, local connections (substation, grid connection), and development, preparation, and coordination of logistics.

The installation at a depth similar to that of a future 1:1 scale model is intended to ensure direct transferability of results from the areas of installation, transport, and operation to a 1:1 scale system (better usability of the results). The operating data obtained from the trial will support further development towards a 1:1 scale model and provide German industry and research partners with a decisive global advantage in the market for innovative pumped storage technologies.

This is helped by the fact that the concept offers numerous synergies with the offshore oil & gas industry and the wind industry. For example, cables, logistics infrastructure, pump turbines, ships, measurement technology, sensor systems, and corrosion protection can be adapted.

~ai-d6efa8a0-f68b-4c8f-b866-a4541ab7b34c_ — © sperra
StEnSea principle in coastal regions

Current challenges include the system integration of the individual components and new control and operating strategies for the storage facility. Further challenges relate to installation, logistics, and the corresponding electrical cable connections, which must be applied and developed offshore for this technology for the first time.

Parameters	StEnSea System 1:3 (California)	StEnSea System 1:1
Outer diameter/ m	10	30
Weight/ t	1,000	20,000
Water depth/ m	500 - 700	600 - 800
Capacity/ MWh	0.5 - 1	20
Power/ MW	0.5 - 1	5 - 7
Efficiency	0.60	0.80

645622002 — © sperra
Principle of manufacturing and transporting full-scale spheres.

Funding: Federal Ministry for Economic Affairs and Energy

Functional principle and follow-up project

Theme Page

Functional principle Ocean pumped storage power plants

Theme Page

Project Page

Predecessor project StEnSEA

StEnSEA

Research Project StEnSEA 2.0