Navantia Installs First Third-Gen Hydrogen-Based AIP System on S-80 Class Submarine

Navantia’s Cartagena shipyard has installed a hydrogen-based Air Independent Propulsion (AIP) system into an S-80 class submarine, marking the first time a third-generation AIP system has been integrated into a submarine.

This technology allows the Spanish Navy's submarines to stay submerged far longer than conventional diesel-electric models, which require resurfacing every few days for recharging.

The AIP system, branded BEST (Bio-Ethanol Stealth Technology) by Navantia, enables submerged battery recharging using bioethanol reforming, a renewable energy source derived from organic materials. This process generates a hydrogen-rich stream, which, when combined with oxygen, powers a fuel cell to produce electricity silently. Unlike earlier systems used by other navies, this innovation eliminates the need for stored hydrogen, enhancing safety and operational autonomy.

The contract for four S-80 submarines for the Spanish Navy was awarded to Navantia in 2004. Construction began at Navantia's Cartagena facilities in 2007, and the long-awaited vessel was unveiled in 2021 following a series of significant delays. The lead submarine embarked on its maiden voyage in May 2022.

This class of submarines is capable of engaging in sea-to-land attacks, intelligence gathering, surveillance, reconnaissance activities, anti-surface warfare, and anti-submarine warfare. Their bioethanol fuel cell AIP (Air Independent Power) system, recognized as BEST, enables extended underwater operations by recharging batteries even when submerged. The submarine is equipped with three primary weapons: the DM2A4 heavyweight torpedo, the UGM-84 Sub-Harpoon anti-ship missile, and SAES seabed mines. It also has the capability to deploy the UGM-109 Tomahawk land attack cruise missile.

The S-80 class submarine has an operational crew of 32 sailors and provisions for eight additional embarked personnel. It can reach underwater speeds of over 19 knots and has a maximum depth capacity of more than 300 meters. It measures approximately 80 meters in length, 7 meters in diameter, and has a submerged displacement of 3,000 tons.