Analysis and modelling of innovative technologies on natural gas transportation and distribution networks

Renewable energy sources (RESs), such as wind, solar and biomass, are the keystone of the energy policy of the EU to fulfil the target of a carbon neutral economy by 2050. However, the integration of a significant share of RESs pose significant challenges to the EU energy systems as it requires, on the one hand, storing large energy volumes to match intermittent renewable supply with the pattern of energy consumption and, on the other hand, transporting renewable energy from where it can be most efficiently and feasibly produced to where it is consumed. To overcome such challenges, it will be effective to consider the reuse of the existing natural gas (NG) infrastructure. The latter will play a crucial role in the development of a decarbonized energy system based on a large usage of RESs due to its widespread presence and its capacity to provide a cost-effective option for transporting and storing large amounts of energy for long-term period exploiting the NG transportation and distribution networks, as well as the storage complexes of the existing NG infrastructure. This thesis aims to address, with a multi-thematic approach, the issue of innovative uses of, as well as the development of innovative technologies on, NG transport and distribution networks. To this aim, a number of five case studies were investigated to: i) evaluate the fault management strategies for NG distribution networks to minimize the disservice and to define possible structural improvement measures; ii) assess the technical feasibility of the Power to Gas concept to store intermittent RESs; iii) analyse the impact of hydrogen injection on NG networks; iv) evaluate the effectiveness of the equilibrium gasification models as a modelling tool for the design and optimization of biomass gasification systems integrated into polygenerative plants coupled with energy networks. Results of this thesis provide useful insights to researchers, designers and policy makers, filling some of the gaps highlighted in the existing scientific literature in all the analysed areas.