DRDO, L&T Ink Pact To Build AIP Modules For Scorpene-Class Subs

The Defence Research and Development Organisation (DRDO) and Larsen & Toubro (L&T) have signed a contract for the realisation of two Air Independent Propulsion (AIP) system modules for 'Kalvari' class submarines of the Indian Navy. An AIP module extends the endurance of conventional submarines and is a niche technology with just a few countries.

"These modules constitute the core of the fuel cell-based AIP System, indigenously developed by the Naval Materials Research Laboratory (NMRL) of the DRDO with L&T as prime industry partner, an association spanning more than a decade. The Energy Modules (EMs) comprising fuel cells produce the required power, along with on-board hydrogen generation," L&T said in a statement.

The manufacturing, integration and factory acceptance trials of the EMs would be undertaken in its AM Naik Heavy Engineering Complex at Surat, L&T said, adding the EMs would be supplied for integration into the AIP Plug that would be retrofitted into the submarine.

Further, it stated that the technology of this indigenous AIP system was a unique one that generated hydrogen on demand thereby obviating the need for carrying hydrogen onboard which was a major safety concern for a submarine. "It is pertinent to mention here that principally this technology is a green one since the by-product of the reaction is non-polluted water which can be released into the oceans."

L&T is the recipient of Transfer of Technology (ToT) for the AIP system from the DRDO and the ToT documents were handed over to L&T by the Defence Minister Rajnath Singh during Aero India 2021.

In January, DRDO and Naval Group of France, the manufacturer of Scorpene-class submarines, signed an agreement to fit the indigenous fuel cell based AIP system on INS Kalvari, the first Scorpene-class submarine when it goes for its first refit in the end of 2024 or early 2025.

Subsequently, AIP modules are planned to be installed on all Scorpene submarines. Six Scorpene submarines are being built under Project-75 by MDL under technology transfer from Naval Group of France under a $3.75-billion deal signed in October 2005.