Long distance renewable-energy-sources power transmission using hydrogen-cooled MgB_2 superconducting line

摘要

Renewable Energy Sources (RES) exploitation for electric energy and hydrogen production has been identified as one of the leading ways towards a future sustainable energy system. Hydrogen can be stored and transported in gaseous (GH_2) or liquid form (LH_2). When large hydrogen storage is required, liquefaction can be convenient with respect to compression, because of its higher storage density. LH2 can also be used as a coolant for superconducting lines, acting at the same time as energy vector and cryogen. In particular, in this paper we focus on the MgB_2 material mainly due to economic considerations and working temperature match with LH_2. A system for large scale RES exploitation allowing flexible and controlled delivery of electric energy and LH_2 is presented. For the thermo-hydraulic design, a method is proposed which resorts to compressible fluid equations put in a convenient simplified form. A case application with 20 km distance between cooling stations is considered, and the need of taking into account LH_2 compressibility for pipeline design is shown.