In order to successfully account hydrogen as a long-term solution to the energy transition problematic, its underground storage becomes crucial to guarantee a continuous supply throughout the year, whereas green hydrogen is generated from strong fluctuating energy sources, such as solar and wind.

The main objective of the project DESSERT (GA. No 101157797) is the design, manufacturing and validation of a new advanced threaded production string to be used for underground storage applications. After having selected the steel types to be implemented for the pipes and the representative geometrical and operational parameters belonging to real storage facilities, a validation process will take place. This validation process will be carried out by means of a series of experimental tests, which will allow to make reliable statements of the threaded production string regarding the safe continuous hydrogen storage in underground formations.

In contrast to other projects, this experimental work will fully reflect the load scenario found along the gas injection and withdrawal cyclic operations during the hydrogen storage service, in particular investigating the effect of alternating pressure loads on the materials and connections used. The test program will be divided into lab scale and full-scale tests. The lab scale tests determine how the mechanical properties of the steels are affected, product of its possible embrittlement. Permeability tests and galling tests will be also performed as part of the lab scale test program. For the full-scale tests, a new testing procedure will be developed, derived from the existing oil and gas standards ISO 13679 and API 5C5, adjusting the testing loads sequence since hydrogen will be used as a working gas. Objective is to test the full-scale newly designed threaded connection to prove its sealability to the real loads acting on the pipe string during its service.