Subsea Storage Revolution
Inside Pleuger’s role in transforming
renewable energy storage

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Pleuger, a leading innovator in underwater motor pump technologies, announces its pivotal role in advancing subsea energy storage with the StEnSea (Stored Energy in the Sea) project.

Project Overview

Pioneering energy storage

How Pleuger and partners are harnessing the power of the Ocean

The StEnSea project, initially conceived by the German Fraunhofer Institute, seeks to revolutionise long-duration energy storage by adapting the principles of pumped storage hydropower for subsea environments.

Since the project's early development in 2012, and in partnership with Fraunhofer IEE and Sperra, Pleuger's expertise in submersible pump systems is helping facilitate a new era of renewable energy storage solutions.

project picture

How it works

The project utilises a unique approach to energy storage by placing hollow concrete spheres on the seabed at depths of 600 to 800 meters. When electricity demand is low, these spheres are emptied of water using PLEUGER’s specially designed submersible pumps to store potential energy.

During peak demand, water is allowed to flow back into the spheres, turning the pumps into turbines that generate electricity. This innovative method mirrors the functionality of traditional pumped storage hydropower but adapts it for the subsea environment, leveraging ocean pressure to store and release energy efficiently.

International Support of the Project

StEnSea

[Stored Energy in the Sea]

The StEnSea project has received substantial financial backing from both the U.S. and German governments, highlighting its significance and the confidence of its potential global impact.

$4 million

awarded to the project by the U.S. Department of Energy Water Power Technologies Office (WPTO), underscoring the importance of developing innovative energy storage solutions that support the country's renewable energy goals.

€3.7 million

committed to the project by the German Ministry for Economic Affairs and Climate Action (BMWK), highlighting the critical role of international collaboration in advancing sustainable technologies.

"The global energy transition demands transformative, scalable solutions, and Pleuger is leading the way. Our ‘Stored Energy in the Sea’ project aligns with our strategy to expand in renewables. Kudos to our brilliant engineers, whose expertise drives these cutting-edge solutions."

Technological Advancements

Technical Challenges

Operating at depths of 600 meters and beyond requires precision engineering. PLEUGER’s submersible pumps are designed to withstand extreme pressures.

Modularity and Scalability

PLEUGER’s pumps are ideal for modular and scalable systems. Suitable for global deployment in coastal areas and deep lakes.

Global Deployment Sites

A comprehensive GIS analysis revealed potential sites for deployment: Off the coasts of Norway, Portugal, the U.S., Brazil, and Japan.

Environmental Benefits

Reduces environmental impact. Avoids land-use conflicts common with traditional pumped storage hydro.

Application in Artificial Lakes

The system is scalable and suitable for natural or artificial deep lakes, such as flooded open-pit mines.

Press Kit

Download the comprehensive StEnSea project press kit, including technical details, visuals, and additional media resources.

Download Press Kit

Impact

This ambitious initiative addresses the urgent need for scalable, efficient energy storage solutions that can integrate renewable energy sources, stabilise power grids, and reduce reliance on fossil fuels. By leveraging PLEUGER’s custom pump systems, the project is set to deliver a groundbreaking, modular subsea pumped hydroelectric storage system that stores energy invisibly beneath the ocean’s surface.

Future Outlook

Advancing technologies for a more sustainable future

PLEUGER has been involved with StEnSea since its inception, contributing to the development of the first prototype with a specially designed underwater pump. Now, with this substantial funding and international partnership, the project is scaling up to include a 10-meter prototype capable of generating 0.5 MW of power at depths exceeding 600 meters.
The technical challenges of operating at such depths are formidable, requiring robust engineering and precision. PLEUGER’s specialist pumps are designed to operate efficiently under extreme pressures and in harsh environments, providing reliable energy generation and storage in a compact form factor. This makes them ideal for the modular and scalable design envisioned for StEnSea, capable of deployment near coastal cities around the world.
“Pumped storage power plants are particularly suitable for storing electricity for several hours to a few days. However, their expansion potential is severely limited worldwide. Therefore, we are transferring their functional principle to the seabed – the natural and ecological restrictions are far lower there. In addition, the acceptance of the citizens is likely to be significantly higher."

Continued commitment to renewable energy innovation

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Partners

Pleuger is a specialist in the design, manufacture and service of submersible motors and pumps, thrusters and plunger pumps, and a key player in the renewable energy sector.

Headquartered in Miami, USA, with manufacturing in Hamburg, Germany, and Orleans, France, and a service centre in Torrington, USA.

Headquartered in Colorado, with offices in California, New York, and Virginia, Sperra is dedicated to pioneering the next generation of renewable energy solutions through automated construction. The company is developing a suite of 3D printed concrete products, including wind turbine towers and anchors for floating solar, wave, and wind energy systems.

The Fraunhofer IEE, based in Germany, is one of the world’s leading applied research organizations. It plays a crucial role in the innovation process by prioritizing research in key future technologies and transferring its research findings to industry in order to strengthen Germany as a hub of industrial activity as well as for the benefit of society.

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Funder

Water Power
Technologies Office

The U.S. Department of Energy Water Power Technologies Office supports research, development, demonstration, and deployment of innovative technologies to advance marine and hydrokinetic energy systems and hydropower.

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People in the project

“Our involvement in the StEnSea project underscores PLEUGER's commitment to innovation and sustainable energy solutions. With the significant support from both the U.S. and German governments, we are transforming energy storage and contributing to a future where clean energy is more accessible and reliable for everyone."

Sebastian Rose

Head of Engineering at Pleuger

“This project is a major step toward proving out and commercializing this critical technology. We are very excited about the international collaboration on this project with Fraunhofer IEE and PLEUGER, and are grateful that the WPTO recognizes the tremendous potential of this work. Energy storage is key to fully decarbonizing our electric grid - SPSH coupled with 3D-printed concrete will accelerate the energy transition using local labor and materials."

Jason Cotrell

CEO Sperra

“Storing and releasing surplus energy generated by renewable sources is a complex challenge, but this project could be a crucial piece of the puzzle. By enabling efficient energy storage at sea, we are helping to facilitate a truly renewable energy era, supporting a future where clean energy will be consistently available to meet demand."

Edris Faez

Team Leader Engineering (R&D)

“At Pleuger not only what we do matters, but how we do things. Utilizing our pumps for renewable energy storage is, in line with our strategy for GHG emission reduction, a natural move."

Dr. Ilva Bönicke

Head of Quality, Safety,
Health & Environment

“Just over 10 years ago, our 'Sea Egg' was a new, but good idea. Capable engineers took it up, developed it further, and are now bringing it to its first application. That's how progress works – everywhere!"

Dr. Gerhard Luther

“The energy transition from fossil to renewable resources can only succeed if electric energy can be stored in huge amounts to economic expenses without remarkable energy losses. The only proven technology which meets these demands so far are hydro power plants. This technology requires two adjacent large water reservoirs (upper and lower basin) at different orthometric heights. Thus the seabed in deep water is the perfect location for hydropower plants, where an empty concrete cavern acts as lower basin and the surrounding high water pressure as upper basin."

Prof. Dr. Horst Schmidt-Böcking

Press Kit

Download the comprehensive StEnSea project press kit, including technical details, visuals, and additional media resources.

Download Press Kit

Project Details

Official project title: StEnSea 2 – Entwicklung und Offshore-Test einer neuartigen Pumpspeichersystems

Project number (German: Förderkennzeichen): 03EI4047A

Funded by: Federal Ministry For Economic Affairs And Climate Action