Under the seas could turn into giant electricity storage facilities

Ocean Grazer initiative, which won the Ces 2022 Innovation award, is developing viable electricity storage technology for offshore wind turbines that are idle when there is excess electricity.

The story, which started in 2014 at the University of Groningen in the Netherlands, managed to attract serious attention when it proved its performance in the tests carried out in 2020 and 2021, first in a flooded mine site and then in a sea port.

Today, as the use of renewable energy sources increases, from the coal power plants where we increase the electricity production by pressing the button; Since we have switched to the if the wind blows or the sun comes out model, either too much capacity is being installed or we have to switch to affordable and sustainable energy storage.

Due to the free electricity market in Europe, more wind energy can be produced than the grid needs on very windy days. In some cases, companies can even pay money on top of the government support they receive. Of course, this is not a very preferred scenario.

For this reason, Ocean Battery, a technology that seems to be very useful for companies investing in offshore wind turbine farms, combines familiar materials and already proven technologies with a different engineering.

Prototype produced for the seabed. The truth is expected to be 70 x 70 meters.

The company’s solution was to use the water pressure on the sea floor like a pumped hydroelectric power plant. Energy is stored and regenerated as it oscillates between a low-pressure freshwater tank made of hard material under the seafloor and a flexible balloon-like reservoir laid on the seafloor.

In the case of a surplus of electricity, the low-pressure water in the rigid part is pushed into the flexible ground, which is subjected to the enormous pressure of the upper seafloor. When electricity is needed, the valve is opened, and the water turbine turns and electrical energy is obtained while the water flows rapidly down to the low pressure part.

The system, which costs half the price and does not decrease in capacity over time like a chemical battery, plans to achieve an electricity storage and discharge efficiency of 70-85%.

If everything goes well and investors show interest and want to use the technology commercially, it is thought that the pilot project can be implemented in 2023. Charge-discharge times can be changed between 30 minutes and 4 hours, depending on the turbine and the pump to be placed in the storage unit, where each module is 10 MWh.