Marijn van Rooij, CTO of Ocean Grazer

“It’s more or less a workplace that sells itself,” says Ocean Grazer Co-Founder and CTO Marijn van Rooij when asked about the working culture at the company. He finds that it’s a great workplace that is building great technology. He encourages people interested in the company to get in touch.

Make it in the North spoke with Marijn van Rooij about Ocean Grazer, a Dutch company that develops hybrid solutions for the offshore renewable energy sector, for its ongoing series featuring Dutch companies that hire internationals. 

Ocean Gazer started out as a research project which van Rooij joined in 2014 for his master graduation project. He was later employed by the University of Groningen to continue working on the concept until he co-founded the company in 2018.

At the moment, Ocean Grazer is seeking to strengthen its engineering, project management, and business development side. If someone with the required expertise needs a work permit, Ocean Grazer is willing to facilitate the process.

“In general, for us it doesn’t really matter what background a person has. We are aiming for global deployment so it’s good to have different backgrounds,” said van Rooij. 

He finds working at Ocean Grazer great. “The renewable energy sector is changing day by day,” explains van Rooij and the technology the company is working on is currently in high demand in light of the ongoing energy transition.

Van Rooij finds that Groningen is a good fit for Ocean Grazer due to its ecosystem featuring multidisciplinary resources on various levels.

The Ocean Grazer team is currently working on its Ocean Battery, an energy storage system for offshore and inshore waters. 

According to van Rooij, almost 95% of all global energy storage is pumped-storage hydroelectricity. This usually happens in mountainous regions where energy is pumped upwards and then flows down into turbines at a lower altitude to generate electricity. Ocean Grazer uses a similar principle and adapted the technology to the offshore environment.

“Instead of having pumped-storage hydroelectricity in mountains, we adapted it for waters and deeper waters,” van Rooij explained, adding that, “instead of mountains, we are using the depth of the ocean and the pressure of water to store potential energy.”

“We do that by burying large rigid reservoirs in the seabed filled with water. If there’s a surplus of energy, this is used to drive pumps that empty the reservoir, pumping the water into the ocean,” said van Rooij. Once there’s no longer a surplus and there’s a need to generate electricity, a valve is opened which allows water to flow back into the system under pressure. As the water flows back in, it drives turbines which then generate the electricity.

“What makes us unique is that we have managed to develop it as a closed system. So we are not actually pumping sea water in and out,” explains van Rooij.

Aside from the marine life, sea water creates a harsh environment for the energy storage system. This puts a strain on the system and reduces its lifetime.

“We empty our reservoirs into a large flexible bag. This allows us to keep the system closed. The water could either be fresh water or one-time conditioned sea water. The internal water utilises the hydrostatic pressure of the ocean while being kept separated from the actual sea water,” says van Rooij.

Do they get your attention? Want to contribute to developing and marketing this awesome invention? Check out their company page!

Video by Julia Dumchenko and Daindra Utami. Article and interview by Christoph Schwaiger.

This article is part of Make it in the North‘s company spotlight series that highlights Northern companies hiring internationals. This article is originally published in The Northern Times for Make It in The North.