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FEB student wins energy battle and will feature on National Geographic Channel

06 December 2012

Martin Grebhahn, pre-Master student in Marketing at the University of Groningen and his team found an energy saving solution, which made them win the NRG battle of sixty teams. The team will have the opportunity to explain their new idea in a short documentary for the National Geographic channel, on air in January. Filming starts next week.

Winning team (Martin on the left)
Winning team (Martin on the left)

The NRG Battle is a competition to solve a specific energy problem. Martin and his team, with students from Twente and Delft, came up with a way to improve the efficiency of “Blue Energy”, the energy generated by mixing salt and fresh water. The business case they solved was for Fujifilm Tilburg, who are currently developing new membranes. The NRG finals with fourteen remaining teams were held on November 20th at the Energy Delta Convention in Groningen.

Five-fold increase

In the documentary on the National Geographic channel, Martin and his team will explain their solution. Blue Energy is normally produced using water from the sea and fresh water from rivers. The disadvantage is that fresh water from rivers is competing with the supply of drinking water. Also the salt gradient between fresh and salt water is too small for a high energy production. The team found that it is possible to produce more energy by using a much more salty solution next to the fresh water. In first lavatory experiments they measured a possibility of nearly five-fold increase.

In addition, the team came up with a solution to avoid having to dump the mixed brackish water. They made it a closed system called 'RED Loop Energy': By distilling the mixed water they managed to get salt and fresh water again. Furthermore, it is possible to use the waste heat of any large industry park, e.g. the port of Rotterdam, to supply the energy production unit. Not only that the jury awarded the first price to the team, Fujifilm is very keen about the developed solution and indicated to further develop the process.


“I’m really proud that we can show our idea to a wider audience via the National Geographic Channel”, says Martin Grebhahn, “And I’m looking forward to the filming that will take place on 10 December.” Grebhahn is having a ‘prizewinning’ year: In September he won a talent award of FEB!

More information
Contact: Martin Grebhahn,, 0031 682 008282

Winning team at the Energy Delta Convention
Winning team at the Energy Delta Convention
Team working in the lab on their energy solution
Team working in the lab on their energy solution
Last modified:11 April 2019 09.51 a.m.

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