A fuel cell mixes hydrogen with oxygen in such a way that it does not burn but instead reacts chemically, to make water and electricity. In other words, it's the reverse process to the electrolyser.
The Surf 'n' Turf fuel cell is supplied by Arcola Energy and will provide electricity on demand for ships and activity within Kirkwall Harbour. Heat produced by the fuel cell as a byproduct will be piped into nearby buildings.
Surf 'n' Turf is laying the foundations for hydrogen to be used at sea. That involves proving the technology on dry land, and letting potential users get hands-on. The fuel cell is designed to marine standards, so it can act as a training rig for ship engineers and crew members.