Project-75I: German Shipbuilder to Provide Stealthy AIP Submarines with Lithium-Ion Batteries to Indian Navy

 

The Indian Navy is pursuing the acquisition of six submarines under its Project-75I, which aims to integrate Fuel Cell Air-Independent Propulsion (AIP) technology with Lithium-ion batteries. This combination will enable the submarines to remain submerged for extended periods and move swiftly without compromising their stealth.

The focus of the Indian Navy is not on having the largest or fastest submarines but rather on achieving superior stealth and lethality. German shipbuilder ThyssenKrupp, a leading contender for the contract, has proposed its 214-class submarines, which incorporate advanced AIP technology and are tailored to Indian requirements. These submarines will be an enhanced version of the 214 class, featuring advanced sensors, combat systems, and Lithium-ion batteries, all while maintaining stealth capabilities.

Dr. Christian Frühling, Program Head for Project-75I at ThyssenKrupp Marine Systems (tkMS), emphasized that their unique AIP solution and proven submarine design would be game-changing for the Indian Navy. The AIP system provides long-range endurance at low speeds, while the Lithium-ion battery enables high-speed cruising, allowing the submarines to cover extensive areas like the Bay of Bengal while remaining submerged.

The hydrogen-powered AIP technology allows the submarines to stay submerged for up to three weeks, significantly reducing the need to surface and enhancing stealth. The 212 and 214 class submarines operate silently, launching torpedoes stealthily and featuring countermeasures against enemy torpedoes. These submarines can also "bottom" on the ocean floor, conserving energy and extending mission duration while using passive sonar to detect targets.

Efficient energy systems are crucial for the Indian Navy, which currently has only 16 conventional submarines against a requirement for 24. Most of these submarines are over 30 years old, making Project-75I a high priority.

AIP-based submarines are more cost-effective and easier to maintain than nuclear-powered ones. They have modular fuel cell systems and smaller crews. The German government, which initially hesitated when the tender was issued three years ago, now supports the project. In March 2024, the German Navy provided its submarine for the Indian Navy's evaluation.

TkMS, confident in its technology, remains the only company with sea-proven fuel-cell-based AIP systems. The 214-class submarines are already in service with Greece, Portugal, Turkey, and South Korea. The Indian Navy, which operates 209-class submarines, has partnered with Mazagon Dockyard Limited (MDL) for repairs and refurbishments. TkMS and MDL jointly produced four submarines for the Indian Navy and are now bidding together for Project-75I.

In Project-75I, the submarines will be built in India from the first unit onward, with TkMS providing design and critical components. MDL will lead the project, with the first submarine expected to be completed seven years from the contract date, followed by one submarine annually.

The field evaluations for Project-75I are set to conclude by June. Spain's Navantia is also competing for the contract but lacks operational AIP technology. Given India's urgent need for advanced submarines to counter China's growing maritime presence, a government-to-government contract to build these submarines in India is a possibility.