Building Innovative Green Hydrogen Systems in Isolated Territories
May 2016 - April 2022


BIG HIT builds on foundations laid by the Orkney Surf ‘n’ Turf initiative, which will see production of hydrogen on the islands of Eday and Shapinsay using wind and tidal energy.

Renewable electricity generated on the islands of Eday and Shapinsay is used by electrolysers to produce hydrogen, by electrolysis of water. This hydrogen is then stored as high pressure gas in the tube trailers, which can be transported to mainland Orkney.

BIG HIT uses two state-of-the-art proton exchange membrane (PEM) electrolysers. The  Shapinsay electrolyser is 1MW capacity and Eday electrolyser is 0.5MW capacity, both located close to the renewable generation assets. The hydrogen acts as an energy-storage medium which can later be converted back into heat and power for buildings and vessels in Kirkwall harbour, as well as the fuel for the operation of zero-emission hydrogen vehicles in and around Kirkwall.

These two PEM electrolysers will produce about 50 tonnes of hydrogen each year from constrained renewables. This ‘zero carbon’ hydrogen can be used to heat local buildings, and will also be transported by sea ferry to Kirkwall in 5 hydrogen tube-trailers. In Kirkwall a 75 kW hydrogen fuel cell will supply heat and power for several harbour buildings, a marina and 3 ferries (when docked) in Kirkwall. And finally, a hydrogen refuelling station in Kirkwall will fuel the 10 Symbio hydrogen fuel cell road vehicles.

BIG HIT will demonstrate the Orkney Islands of Scotland as a replicable Hydrogen Territory, using curtailed renewable energy generated locally to produce hydrogen which can then be used as a clean energy vector to store and use valuable energy for local applications. The hydrogen will be used near to the point of production on Eday and Shapinsay wherever possible.

BIG HIT will demonstrate use of hydrogen as a flexible local energy store and vector, transporting hydrogen by tube trailer to the Orkney mainland. Here it will be used to demonstrate real end-use applications for hydrogen including auxiliary power and heat for ferries in Kirkwall harbour, fuelling a fleet of hydrogen range-extended light vehicles, and heating for buildings in the Kirkwall area.

The learning from BIG HIT about the benefits of using hydrogen with renewable energy sources in the Orkney Islands will support the much wider replication and further deployments of renewable energy with fuel cell & hydrogen technologies in isolated or constrained territories.


FHA will coordinate and manage BIG HIT, being present in all work packages to ensure successful execution of tasks. In addition, FHA will lead WP2, being in charge of the preliminary system design and conduct much of the modelling.

Funding entities