India’s Defence Research and Development Organisation (DRDO) is poised to install an indigenously developed Air Independent Propulsion (AIP) system on the INS Kalvari during its major refit scheduled for September next year. This initiative marks a significant milestone in India’s efforts to bolster its maritime capabilities and counter emerging regional threats effectively. The AIP system, currently in the production phase following successful trials, will enhance India’s submarine fleet’s operational endurance and augment its stealth and survivability in critical maritime environments.
The integration process involves complex modifications to accommodate the new AIP technology, underscoring India’s growing naval defence research and development prowess. After integration and successful trials on INS Kalvari, the remaining five Kalvari-class submarines will also be fitted with the AIP system. Additionally, the Indian Navy is in price negotiations to procure three more Kalvari-class submarines, which are likely to be equipped with the AIP system during their construction phase. This comprehensive upgrade positions India as a key player in enhancing regional maritime security.
Advancing Kalvari-class Submarines with DRDO’s AIP System
Traditional diesel-electric submarines rely on diesel engines that require atmospheric oxygen to burn fuel and generate electricity to recharge batteries. This process necessitates periodic surfacing or snorkelling every 2-5 days, exposing submarines to detection by sonar systems, maritime patrol aircraft radars, and helicopters scanning for periscopes. These surface intervals compromise stealth and increase vulnerability during critical missions.
In contrast, Air Independent Propulsion (AIP) systems represent a significant technological advancement. AIP systems, such as those utilising fuel cells, steam turbines, and Stirling engines, use stored oxygen to generate electricity, allowing submarines to remain submerged for extended periods without needing to surface. AIP systems enhance mission endurance and operational flexibility by reducing dependency on atmospheric oxygen.
The DRDO has developed an advanced AIP system based on fuel cell technology, known for its efficiency and safety. Fuel cells generate electricity through a chemical reaction between hydrogen and oxygen, requiring significantly less oxygen than traditional diesel engines. The DRDO AIP system specifically allows Kalvari-class submarines to stay submerged for up to 14 days. This fuel cell-based AIP system not only enhances endurance but also reduces acoustic and thermal signatures, enhancing overall stealth capabilities.
This technological leap strengthens India’s maritime dominance strategy in the Indian Ocean region by mitigating detection risks and ensuring sustained operational effectiveness in diverse naval environments.
India’s Strategic Move Amid Pakistan Navy Modernization
In 2015, Pakistan finalised a substantial $5 billion agreement with China to acquire eight Hangor-class submarines equipped with advanced Air Independent Propulsion (AIP) systems. Following several delays, China launched the first of these submarines in April 2024, with delivery scheduled in the next 2-3 years. This development highlights significant advancements in submarine capabilities within the region, particularly in AIP technology. The deployment of these advanced submarines presents strategic implications for India’s maritime security framework.
India’s proactive integration of AIP on Kalvari-class submarines underscores its strategic imperative to uphold naval supremacy and ensure regional stability. By enhancing operational capabilities and stealth, India aims to effectively navigate and counterbalance evolving regional dynamics, safeguarding its maritime interests amidst these emerging challenges.
Vinay Sadham
