The S-80 Programme successfully completes the development of the Air-independent Propulsion System (AIP)


After the closure of the pressure hull on the first submarine in the class, the S-81 “Isaac Peral”, Navantia’s developed S-80 Programme passed another milestone when it successfully completed the final tests for consolidation of the Air-independent Propulsion System (AIP).

Conventional submarines require daily snorkelling operations, to recharge their batteries with the use of diesel engines, which exposes them to detection and attack. The AIP system minimises this exposure by recharging the submarine’s batteries during immersion with a fuel cell, which uses hydrogen produced by processing bioethanol and oxygen to generate electricity, enabling the submarine to sail for weeks without surfacing.

Having this technology adapted to the demanding needs of an underwater platform, by the deadlines that had been set, was a challenge for the S-80 Programme. To guarantee a successful outcome, the Spanish Ministry of Defence decided to commission the development of the bioethanol processor, one of the system’s most complex elements, to two Spanish companies at the same time: Abengoa Innovación and Técnicas Reunidas. Both companies have demonstrated their great technological skill by satisfactorily complying with all the milestones, requirements and deadlines established in the programme.

After a strict decision-making process, where all the technical and programme factors were analysed, the Spanish Ministry of Defence selected the Abengoa system as being the optimum solution to be fitted to the S-80 Class submarines, and thanked Técnicas Reunidas for its effort and commitment to the S-80 Programme. The first submarine to be equipped with this operating system will be the S-83, “Cosme García”, where the system will be installed in July 2021. Submarines S-81 and S-82, currently under construction, will be upgraded with this system during their first major overhaul.

The AIP system will provide the Spanish Navy with hitherto unmatched tactical and stealthiness capacities, making the S-80 submarines a global benchmark.