To further advance a world powered by hydrogen, it is essential to take advantage of the environmental benefits of using surplus industrial hydrogen to energy conversion. In this paper, the integration of this renewable source in a hydrogen supply chain has been analysed with the following considerations, (1) the techno-economic modeling is applied over the 2020–2050 period, at a regional scale comprising the north of Spain, covering the main sources of surplus hydrogen in the region, (2) the supply chain feeds fuel cell devices powering stationary and mobile applications and, thereby stablishing the quality standards for the upcycled hydrogen and, (3) a mixed-integer programming model (MILP) is formulated to predict the optimal integration of surplus hydrogen. The advantages of this research are twofold, (i) on the one hand, it provides the methodology for the optimal use of surplus hydrogen gases promoting the shift to a Circular Economy and, (ii) on the other hand, it contributes to the penetration of renewable energies in the form of low cost fuel cell devices to power stationary and mobile applications. The results show that the combination of all the infrastructure elements into the mathematical formulation yields optimal solutions with a plan for the gradual infrastructure investments over time required for the transition towards a sustainable future energy mix that includes hydrogen. Thus, this work contributes to improving the environmental and economic sustainability of hydrogen supply chains of upcycling industrial surplus hydrogen.