The recent decline by France’s Naval Group to participate in the P-75I Project has brought into focus the country’s need for Air-Independent Propulsion (AIP) technology. This article aims to elaborate on the concept of AIP, the P-75I project and its implications for India’s naval power.
Understanding the P-75I Project
Initiated in June 1999, the P-75I project was put forth by the Cabinet Committee on Security which approved a 30-year plan for the navy to construct and incorporate 24 submarines indigenously by 2030. This project was divided into two production lines—P-75 and P-75I. Each line was planned to produce six submarines entirely constructed in India at an estimated cost of Rs. 43,000 crore. Currently, the six P-75 submarines use diesel-electric engines but can adopt AIP technology later.
Exploring the Concept of Air Independent Propulsion (AIP)
AIP is a technology used in non-nuclear submarines. Ordinary diesel-electric submarines have to surface almost every day to obtain atmospheric oxygen for fuel combustion. With AIP system, this requirement is reduced to once per week, resulting in increased efficiency and reduced detection risk. The Naval Materials Research Laboratory (NMRL – DRDO) has developed an indigenous AIP considered one of the ambitious projects for the Navy.
Fuel Cell Based AIP System
In a fuel cell based AIP, an electrolytic fuel cell combines hydrogen and oxygen to release energy. Water is the only waste product, leading to minimal marine pollution. These cells are notable for their high efficiency and low acoustic emission due to the absence of moving parts.
Advantages and Disadvantages of AIP
An AIP system has several advantages over conventional systems. It increases the submerged endurance of a diesel-electric submarine several fold. AIP technology also allows a conventional submarine to remain underwater for more extended periods compared to ordinary diesel-electric submarines, reducing chances of detection.
On the flipside, installing AIP results in a heavier and longer submarine which also requires pressurised liquid oxygen storage onboard. Certain AIP systems like MESMA and the Stirling engine create acoustic noise whereas the unit cost of a submarine fitted with AIP technology increases by approximately 10%.
Indian Submarines: Current Scenario
At present, India has 16 conventional diesel-electric submarines, classified as SSKs. With the commissioning of the last two Kalvari Class submarines under P-75, this count will rise to 18. In addition, India has two nuclear ballistic submarines, classified as SSBN (Submersible Ship Ballistic Missile Nuclear). Upon completion of the P-75I scheme under the 30-year plan, India aims to have six diesel-electric, six AIP-powered, and six nuclear attack submarines.
Overall, the development and implementation of AIP technology offer a strategic advantage in submarine warfare. Despite some drawbacks, embracing such advanced technologies is essential for strengthening India’s maritime security, which is crucial in an ever-evolving geostrategic environment.