All about DRDO’s massive Air Independent Propulsion System tableau!

Defence Research and Development Organisation (DRDO) displayed two tableaux this Republic Day parade 2022, namely, ‘Suite of Indigenously Developed Sensors, Weapons and Electronic Warfare Systems for LCA Tejas’ and ‘Air Independent Propulsion System (AIP)’ developed for the submarines of Indian Navy.

In this segment let’s understand all about the massive Air Independent Propulsion System tableau!

What is Air Independent Propulsion Technology?

Air-independent propulsion (AIP), or air-independent power, is marine propulsion technology that allows a non-nuclear submarine to operate without access to atmospheric oxygen (by surfacing or using a snorkel). AIP can augment or replace the diesel-electric propulsion system of non-nuclear vessels.

The indigenous AIP propulsion system developed by DRDO is a modular system that can be easily configured for any conventional submarine platform. Currently, the system is configured for P75 submarines which got the safety, interface acceptance and permission from the Submarine designer M/s NG France.

How are AIP-fitted submarines different from the rest?

Legacy diesel-electric submarines operate silently underwater for up to 48 hours, but they have to surface within restricted hours to run a generator that recharges their batteries.

These diesel-electric submarines, when they surface, become vulnerable to detection by enemy radar, which easily detect submarine masts or snorkels jutting on the surface of the water.

This vulnerability can be reduced by powering a submarine with an AIP system, that enables underwater operations for up to two weeks. However, AIP-fitted submarines too surface every fortnight for battery charging. But that still makes them difficult to detect as nuclear-powered subs, which can stay submerged indefinitely.

Fuel cell-based AIP – an even better version of the technology

Fuel cell technology-based AIP generates power through the reverse electrolysis of oxygen and hydrogen. In this process, the two elements chemically combine, thereby generating electricity to charge the submarine’s batteries.

This process does not need air rather it requires the storage of highly inflammable hydrogen on board. This is not true of the DRDO’s AIP system, which relies on the innovative Phosphoric Acid Fuel Cell technology.

Ministry of Defence in a statement had said, “AIP has a force multiplier effect on the lethality of a diesel-electric submarine as it raises the submerged endur­ance of the boat, several-fold. Fuel cell-based AIP has merits in performance compared to other technologies.”

The process of  Phosphoric Acid Fuel Cell technology is more rugged and tolerant of fuel impurities, offering longer life and efficiency.

Moreover, it is much safer, since it does not require hazardous Hydrogen to be stored onboard.

“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,” said the MoD.

Only a few countries in the world have access to this unique technology. This technology was created by the DRDO in partnership with academia and industry.


Central Chronicle is daily English Newspaper of Chhattisgarh. Central Chronicle has own website it is first news website in Chhattisgarh.
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