Tractebel and partner companies have developed the world's first offshore infrastructure and processing facilities concept for the storage of hydrogen in offshore caverns. The design study, unveiled by Tractebel Overdick GmbH, outlines what is said to be an innovative solution for large-scale hydrogen storage on the high seas: namely a scalable offshore platform for the compression and storage of up to 1.2 million cubic metres of hydrogen. Underground salt caverns will be used as storage and buffer for the hydrogen produced offshore, before the gas is transported via the pipeline network to the onshore grid.
Green hydrogen from offshore wind energy is becoming an important component of the global energy transition, but current hydrogen production technologies will only make an effective contribution if production rates reach an industrial scale. Enormous amounts of hydrogen from renewable sources will be required to supply future H2 energy demands and offshore sites, says Tractabel, are key to industrial-scale production. Tractebel pioneered an new solution to address this demand in 2019, with the development of its offshore hydrogen platform concept, followed by an optimised, scalable version the following year.
The offshore platform complex consists of a wellhead platform for the operation of the caverns and a series of compression platforms that enable a staged increase in capacity. If required, the plant can also be expanded in the future by additional modules. The study assumes a capacity equivalent to converting 2 GW of green offshore wind power into hydrogen. Extensions and individual adaptations are possible at any time.
The newly designed storage and compressor platforms process 400 000 Nm3/h of hydrogen, which is stored at a pressure of up to 180 bar. This can buffer production peaks, optimise flow rates and thereby enable a more economical design of the export pipeline.
An important contribution to the sustainability of large underground hydrogen storage facilities is that existing offshore infrastructures can directly use green hydrogen instead of other energy sources for their operations, contributing to the decarbonisation of the entire offshore industry.
The North Sea is well suited for the solution due to its geological conditions and underground rock salt formations. The study assumes a total storage volume of up to 1.2 million metre cubed as a starting value for efficient peak coverage of offshore H2 production rates.