This thesis evaluates a hydrogen-assisted bio synthetic natural gas pathway designed for a Danish wheat straw context. The concept separates biomass conversion into slow pyrolysis and volatile upgrading, where pyrolysis produces biochar and a volatile stream that is reformed to syngas and upgraded to methane through catalytic methanation. Renewable hydrogen is supplied via electrolysis to enable stoichiometric control and higher carbon utilisation. The process was modelled in Aspen Plus and the simulation results were used as the basis for a techno-economic analysis and sensitivity assessment. Two layouts were evaluated. One integrates alkaline electrolysis cells and the other integrates solid oxide electrolysis cells.