Subsea Energy Storage System

Revolutionize your offshore energy storage with our economical, enabling subsea solution


With our new subsea energy storage system, based on our membrane-based storage solution for oil and chemicals, you can now store liquid clean energy, such as ammonia or e-methanol, directly on the seafloor.

At water depths of over 70m and temperatures below 39°F (4°C), ammonia stays liquid, and membrane-based storage technology can store clean energy in the form of liquid ammonia as a hydrogen energy carrier. Thus, we offer economical storage of ammonia in liquid form while providing protection for both rig personnel and marine life.

This technology can be used in a variety of applications, like power storage for offshore assets, offshore fueling stations for ships, renewable energy storage with offshore wind turbines, or common storage of ammonia for fertilizer plants.


  • Safe and zero energy subsea storage for all, populated and non-populated areas: Subsea storage at ambient pressure and temperature
  • Flexible size and capacity
  • Easy to design for decommissioning and redeployment: Standard and reusable design

How does it work?

Energy is stored in storage units at ambient hydrostatic pressure by utilizing a flexible membrane. The membrane is protected and secured to the seabed by an external protection structure. The subsea energy storage system consists of the following main elements: storage units, a fluid transfer and refilling system, heating and circulation system, control and instrumentation, power supply, and structure and foundation.

An example with a fixed platform with five 5,000 m³ storage units, gives a total storage volume of 25,000 m³. Energy storage with ammonia, given the density of ammonia, gives 19,000 tons of fuel. Each ton of ammonia gives 5,17 MWh of energy, if it is used as direct fuel. This gives a total power of 98,490 MWh, which will fuel a medium 60 MW platform for 68 days, before re-filling is needed.

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