L&T and Navantia Showcase AIP Submarine Technology on Spanish Submarine for India’s Project 75(I)

Larsen & Toubro (L&T), a key player in India's defence manufacturing landscape, has joined forces with Spanish shipbuilder Navantia to deliver advanced Air-Independent Propulsion (AIP) submarines under the prestigious Project 75(I) program. This ambitious initiative, valued at approximately ₹40,000 crore (around $5.8 billion), underscores India's commitment to bolstering its naval capabilities while advancing its indigenous defence manufacturing ecosystem.

Revolutionizing Submarine Operations with AIP Technology

At the heart of the L&T-Navantia collaboration is the integration of a state-of-the-art AIP system designed to significantly extend a submarine's underwater endurance. By enabling submarines to remain submerged for up to 21 days, the AIP technology minimizes the need for surfacing, a critical factor for stealth and operational efficiency. Navantia demonstrated this cutting-edge system on the S-83 submarine, currently under construction for the Spanish Navy.

The AIP system leverages bioethanol as a hydrogen source, offering a host of advantages:

• Sustainability and Safety: The use of bioethanol, a renewable and widely available fuel, eliminates risks associated with hydrogen storage while ensuring eco-friendly operations. The carbon emissions are offset by the absorption during the feedstock growth cycle, making it a greener alternative to traditional fuels.

• Enhanced Operational Range: The efficient hydrogen generation system enhances stealth and operational range, allowing the submarine to carry out prolonged missions without surfacing for refuelling.

• Simplified Maintenance: The modular and compact design of the AIP system ensures ease of maintenance and repair, boosting reliability during long missions.

Project 75(I): A Strategic Leap for India's Defence

Project 75(I) is a flagship initiative under India’s “Make in India” campaign, aiming to construct six advanced conventional submarines domestically. It represents the first major procurement under the Strategic Partnership (SP) model, which emphasizes collaboration between Indian private firms and foreign Original Equipment Manufacturers (OEMs) for co-development and technology transfer.

This program is a cornerstone in India’s defence strategy, aimed at enhancing local capabilities in submarine design and construction. It also fosters the development of a robust industrial ecosystem that includes small and medium enterprises (SMEs), driving technological innovation and job creation.

The Broader Impact of L&T-Navantia Collaboration

L&T’s extensive experience in submarine construction, including its work on India’s Arihant-class nuclear-powered ballistic missile submarines, positions it as a formidable partner in this venture. Navantia’s expertise in submarine technology further enhances the collaboration's potential to deliver next-generation submarines tailored to the Indian Navy's requirements.

Beyond Project 75(I), L&T and Navantia are exploring opportunities in other defence and green energy sectors. Their partnership reflects a strategic alignment that could open avenues for collaboration in diverse areas, from renewable energy initiatives to advanced military platforms.

Strengthening Naval Power in the Indo-Pacific

With regional security concerns on the rise, the integration of AIP submarines into India’s naval fleet marks a significant leap forward in ensuring maritime dominance. These advanced submarines will provide the Indian Navy with enhanced stealth, endurance, and operational flexibility, crucial for securing the Indo-Pacific against emerging threats.

Project 75(I) is more than a defence acquisition; it is a testament to India’s growing self-reliance and global partnerships. By blending cutting-edge technology with indigenous manufacturing, the program sets a benchmark for future defence initiatives while fortifying India’s position as a maritime power.