DRDO develops fuel cell-based propulsion system for submarines

Defence Research and Development Organisation (DRDO) has achieved an important milestone in the development of Air Independent Propulsion (AIP) System by proving the land-based prototype on 8 March 2021. The plant was operated in endurance mode and max power mode as per the user requirements. The system is being developed by DRDO’s Naval Materials Research Laboratory (NMRL).

AIP has a force multiplier effect on lethality of a diesel electric submarine as it enhances the submerged endurance of the boat, several fold. Fuel cell-based AIP has merits in performance compared to other technologies.
While there are different types of AIP systems being pursued internationally, fuel cell-based AIP of NMRL is unique as the hydrogen is generated onboard.
While a traditional diesel-electric submarine is required to frequently surface in order to recharge its batteries giving it an underwater endurance of just a handful of days and a maximum of sevendays, fuel-cell based AIPs enable submarines to stay underwater for vastly longer periods, increasing their range and turning them into a far more potent and lethal adversary
The announcement comes a day before the Indian Navy inducts its INS Karanj attack submarine. 
The Indian Navy can now proceed with retrofitting all its Kalvari class non-nuclear attack submarines with AIP during their next upgrade scheduled for 2023. 
With the development of the AIP technology, India joins an elite list of countries that includes the United States, France, China, the United Kingdom and Russia. 
The technology has been successfully developed with the support of industry partners L&T and Thermax. It has now reached the stage of maturity for fitment into target vessels.
Defence minister Rajnath Singh congratulated DRDO, Indian Navy and Industry for the achievement.
Secretary DDR&D and chairman of DRDO, G Satheesh Reddy appreciated the efforts of the teams involved in the successful development. He called upon the DRDO fraternity to come up with more such advanced technological achievements by putting extraordinary efforts.