DRDO’s Indigenous AIP System Moves Closer to Kalvari-Class Submarine Integration

India’s efforts to enhance the Indian Navy’s underwater capabilities have achieved a significant milestone with the inauguration of the second phase of work on an indigenous Air-Independent Propulsion (AIP) system, the Defence Ministry said on Saturday.

The AIP system is designed to improve the underwater endurance of diesel-electric submarines by reducing their dependence on atmospheric oxygen, enabling them to remain submerged for longer periods.

The Setting to Work (STW) Phase-2 activity for the AIP energy module, developed by the Defence Research and Development Organisation’s (DRDO) Naval Materials Research Laboratory, was inaugurated at Larsen and Toubro’s AM Naik Heavy Engineering Complex in Hazira, Gujarat.

In the next phase, the energy module will be energised for power generation and subjected to rigorous testing in accordance with Indian Navy protocols, the ministry said. Following the tests, the module is scheduled to be handed over to Mazagon Dock Shipbuilders Limited (MDL) in early 2027 for integration into a Kalvari-class submarine.

Defence Secretary Rajesh Kumar Singh, who also holds additional charge as DRDO chairman and Secretary of the Department of Defence Research and Development, participated in the ceremony virtually. Vice Admiral B Sivakumar, Chief of Materiel of the Indian Navy, and R Balamuralikrishnan, Director General (Naval Systems and Materials) at DRDO, attended the event in Hazira.

Singh congratulated DRDO and its industry partners, commending their scientific efforts and industrial cooperation in advancing the indigenous AIP programme. He also acknowledged the Indian Navy’s support in testing and validating the system at different stages of development.

Emphasising the next stages of the programme, Singh called for efforts to meet the Navy’s planned induction timelines while maintaining stringent safety standards, particularly given the requirements associated with hydrogen and fuel-cell technologies.