The Indian Navy is on the brink of a significant upgrade that promises to reshape its operational capabilities in the face of evolving maritime threats. The integration of the Air Independent Propulsion (AIP) system into the Kalvari-class submarines marks a pivotal moment in India’s naval strategy. With the steel cutting ceremony for the AIP system held at the Larsen & Toubro (L&T) Hazira facility, the momentum is building for a transformation that could redefine underwater warfare for India.
The AIP technology, developed by the Defense Research and Development Organisation (DRDO), is a game-changer for conventional submarines. It allows these vessels to remain submerged for extended periods without the need to surface for air, significantly reducing their vulnerability to detection. Traditional diesel-electric submarines can only stay underwater for a few days before needing to recharge their batteries, but with AIP, that endurance can stretch to two weeks or more. This capability is crucial given the increasing naval presence of adversaries like China and Pakistan in the Indian Ocean.
The INS Kalvari, the first of the six Scorpene-class submarines, is set to undergo a major refit in September 2025, during which the AIP will be installed. This process won’t be a walk in the park; it involves cutting the submarine in half to integrate the AIP system, which adds both length and weight. Such an operation raises questions about the submarine’s operational readiness during the upgrade, but the long-term benefits far outweigh the short-term challenges.
The urgency of this upgrade is underscored by the fact that both China and Pakistan already possess AIP technology. Pakistan has long relied on AIP-equipped French Agosta-90B submarines and is collaborating with China on the Hangor-class submarines, which also feature AIP. With the stakes so high, the Indian Navy must act swiftly to level the playing field. The AIP technology is not just a nice-to-have; it’s becoming a cornerstone of India’s submarine strategy under Project-75I, which aims to procure six additional submarines equipped with AIP.
The competition for Project-75I is heating up, with contenders like MDL and L&T vying for the contract alongside their foreign partners. The German Thyssenkrupp and Spanish Navantia are both offering submarines with AIP capabilities tailored to Indian specifications. The stakes couldn’t be higher; the winner will not only shape the future of India’s underwater fleet but also its strategic posture in the region.
Navantia’s AIP Bioethanol Stealth Technology (BEST) system, which uses bioethanol to generate hydrogen onboard, offers a tactical advantage by allowing submarines to remain submerged longer while carrying more energy. On the other hand, TKMS’s Type 214 submarine boasts a Lithium-Ion battery that enhances long-range endurance and speed. Both technologies promise to elevate India’s combat prowess, but the Indian Navy remains cautious, as none of the tested AIP systems have fully met its stringent requirements yet.
What’s clear is that the Indian Navy is not merely looking to keep pace with its adversaries; it aims to outmaneuver them by becoming the quietest and most lethal force in the Indian Ocean. The successful integration of AIP technology into the Kalvari-class submarines is a vital step in this direction. As the geopolitical landscape continues to shift, the Navy’s ability to operate undetected will become increasingly crucial in safeguarding India’s maritime interests.
The upcoming years will be telling. If the Indian Navy can successfully implement AIP technology and follow through with Project-75I, it will not only enhance its operational capabilities but also send a strong message to adversaries about India’s commitment to securing its maritime domain. The integration of AIP is not just an upgrade; it’s a strategic imperative that could redefine naval warfare in the region.
