Indian Navy's Indigenous AIP System Enters Phase-2 Testing to Boost Submarine Endurance

The Indian Navy's underwater capabilities have moved toward a significant enhancement following the inauguration of the 'Setting to Work Phase-2' activity for an indigenous air-independent propulsion (AIP) system. The Ministry of Defence announced the development on Saturday.

The AIP system is designed to boost the underwater endurance of diesel-electric submarines by reducing their dependence on atmospheric oxygen. The energy module was inaugurated at Larsen and Toubro’s AM Naik Heavy Engineering Complex in Hazira, Gujarat.

The system was developed indigenously by the Naval Materials Research Laboratory (NMRL), operating under the Defence Research and Development Organisation (DRDO). Defence Secretary Rajesh Kumar Singh, who holds additional charge as Chairman of DRDO and Secretary of the Department of Defence Research and Development, attended the ceremony virtually.

Other attendees at the Hazira event included Chief of Materiel of the Indian Navy, Vice Admiral B Sivakumar, and Director General of Naval Systems and Materials at DRDO, R Balamuralikrishnan.

During the next phase, the AIP energy module will be energised for power production. It will undergo rigorous testing according to the Indian Navy’s protocols. Once testing is complete, the system will be handed over to Mazagon Dock Shipbuilders Limited for integration onto the Kalvari-class submarine by early 2027.

Defence Secretary Rajesh Kumar Singh congratulated DRDO and its industry partners for their scientific perseverance and industrial cooperation in the indigenous AIP programme. He noted that the initiative has culminated in a productive reality on the shop floor.

Singh also acknowledged the cooperation provided by the Indian Navy throughout the course of the programme, which included testing and validating at every stage of trials. He emphasized the importance of working toward the next phases of the programme to meet the Navy’s induction timelines. Furthermore, he highlighted the need to maintain an exacting safety culture, which hydrogen and fuel cell systems require without compromise.

"The progression of the indigenous AIP system highlights the growing synergy between India's defence research bodies and private heavy engineering players. For businesses and industrial manufacturers, participating in national security supply chains offers long-term stability and drives advanced technological capability. As these projects move toward commercial and operational integration by 2027, robust collaboration and strict adherence to safety protocols will remain critical for successful execution." — Dr. Shishir Gupta, Founder & CEO, StartupLanes