Navantia, a Spanish shipbuilding company, has achieved a groundbreaking milestone in the S-80 Programme by successfully integrating the first third-generation Air-Independent Propulsion (AIP) system into the 'Isaac Peral' submarine. This technological advancement, named BEST (Bio-Ethanol Stealth Technology), significantly enhances the submerged endurance of Spanish Navy submarines compared to conventional diesel-electric counterparts. By utilizing a bioethanol reforming process to produce a Hydrogen-rich stream along with pure Oxygen for electrical power generation, the AIP system eliminates the need for storing hydrogen on board, offering tactical advantages and increased safety. The event, attended by Admiral Aniceto Rosique Nieto, highlighted Navantia's unique capabilities in international submarine construction tenders. The AIP system not only provides extended operational capabilities but also enhances crew safety and minimizes the required personnel for submarine operation, thus revolutionizing naval technology and defense industry standards.