Soon, weather conditions will dictate the timing of renewable energy production, causing large fluctuations. Dutch engineers at start-up Ocean Grazer have come up with Ocean Battery, a scalable, modular solution for utility scale storage of energy that is produced by renewable sources such as wind turbines and floating solar farms at sea.

Producing renewable energy is crucial for a climate neutral economy. This energy transition requires a significant change in the energy system. More and more solar and wind turbine parks are being realised onshore and offshore to contribute to a sustainable society. The planned global production of offshore wind for the year 2050 exceeds 1150 gigawatt.

To grow to a system where renewable energy is the norm, the biggest hurdle must be solved: energy storage. Ocean Battery seeks to tackle that challenge.

Pumped hydro system

Ocean Battery is a pumped hydro system in a box that provides eco-friendly utility scale energy storage up to GWh scale. The mechanism is based on hydro dam technology, that has proven itself for over a century as highly reliable and efficient.

To store energy, the system pumps water from the rigid reservoirs into the flexible bladders on the seabed. Now the energy is stored as potential energy in the form of water under high pressure. When there is demand for power, water flows back from the flexible bladders to the low pressure rigid reservoirs. Driving multiple hydro turbines to generate electricity.

Ocean Grazer says that test setups prove that the system works and that it achieves high efficiency. The first applications are already being prepared at existing wind farms, where Ocean Battery keeps the grid stable and even offers blackstart possibilities after blackouts.

Offshore storage

Ocean battery provides utility scale energy storage at the source, it can be deployed in existing and new offshore wind farms. In this way, it is possible to reduce local peak loads in the network and optimally match supply and demand.

The Ocean Battery does not require rare earth materials and uses clean water as the energy carrier. The structure is designed to enhance marine life.

Ocean Grazer BV is a spin-off from the University of Groningen. As a small start-up, its engineers are now bringing their development to the market.

Picture by Ocean Grazer.