The Sines H2 Hub aims to take advantage of Portugal’s solar resources and push for a green hydrogen hub centred in Sines. To do so, a 1GW electrolyser is expected to be built by 2030. The gas produced, which will have the same production profile as the solar irradiance, can be injected in the gas grid, distributed by truck or shipped to the Netherlands. Due to hydrogen’s high volumetric energy density, ammonia is considered a suitable energy carrier for the ship­ping option. However, ammonia production requires a stable hydrogen supply ­ which is not compatible with a profile dependant on solar irradiance. To face this issue, a technological option that stands out is using the existing Carriço salt caverns, located 280km north of Sines and connected by pipeline, as a buffer to store the hydrogen during the day and supply it back to Sines at night. This research aims to calculate the levelized cost of hydrogen transmission by pipeline from Sines to Carriço, storage in the Carriço salt caverns and transmission back to Sines. Based on the stabilized hydrogen production, a model is developed and 4 pathways are considered for each of the possible infrastructure combinations: new or retrofitted transmis­sion and new or retrofitted storage. Dependant on the infrastructure selected, the cost model developed found a total levelized cost of hydrogen transmission and storage of: 0.17­-0.25 [€ ⋅ kg(H2)−1]. By considering a competitive green hydrogen production cost of 1­-1.5[€ ⋅ kg(H2)−1], the transmission & storage costs along with the rest of the direct hydrogen supply, will translate into an added 10% expense ­ on top of production ­ to provide a stable hydrogen supply to the ammonia plant. The result, which is aligned with literature, is expected to provide solid input in assessing hydrogen’s price competitiveness and contribute to the decision process of using retrofitted or new infrastructure.