AIP Technology

In Context

  • Recently, the French company Naval Group announced that it is unable to participate in India’s P-75I project  due to conditions mentioned in the request for proposal (RFP) related to the Air Independent Propulsion (AIP) system.

About AIP Technology

  • Submarines are essential of two types: Conventional and Nuclear.
    • Conventional submarines use a diesel-electric engine and must surface daily for oxygen for fuel combustion
      • If fitted with an Air Independent Propulsion (AIP) system, the sub needs to take in oxygen only once a week.
    • Many naval powers, including India, have acquired nuclear-powered submarines for deep-sea operations.
  • AIP is a mechanism that allows the batteries to be charged even while the boat is submerged. 
    • However, even with AIP, the submarine needs to surface every three weeks or so. 
  • It offers the possibility of increasing underwater endurance by a factor of up to 3 or 4, which reduces the indiscretion ratio significantly.
  • It has a force multiplier effect on the lethality of a diesel-electric submarine as it enhances the submerged endurance of the boat severalfold
    • Fuel cell-based AIP has merits in performance compared to other technologies.
  • India has been working to develop AIP technology indigenously as well.
    • There are different types of AIP mechanisms available and India is looking for the P-75I project to be AIP based on fuel cells. 
      • These cells convert chemical energy into electrical energy, recharging the batteries of the submarine.
  • Significance 
    • It helps to make the diesel generator less dependent on surface air.
  • It is known to deliver better performance compared to other technologies. 
  • Downsides 
    • Installing AIP increases the length and weight of the boats, requires pressurised liquid oxygen (LOX) storage on-board and supply for all three technologies”. 
    • Also, “MESMA and the Stirling engine have some acoustic noise from moving parts; and the submarine’s unit cost [increases] by around 10%.”

What is the P-75I project?

  • In June 1999, the Cabinet Committee on Security approved a 30-year plan for the Navy to indigenously build and induct 24 submarines by 2030.
  •  In the first phase, two lines of production were to be established — the first, P-75; the second, P-75I
    • Each line was to produce six submarines.
  • The contract for P-75 was signed in 2005 with the Naval Group, then known as DCNS, in partnership with Mazagon Dock Shipbuilders Ltd (MDL).
    • The first Kalvari Class (Scorpene Class) submarine under the project was commissioned in December 2017. 
  • While P-75 deliveries were delayed, P-75I has seen long delays even before it has kicked off. 
    • The first Request for Information was issued in 2008, then again in 2010, but the RFP was issued only in July 2021.

Source:IE

 
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