Insight: What is the way forward for the propulsion systems of conventional submarines?
In September 2024, Naval Group was awarded a contract to deliver four Orka-class submarines as part of the Walrus Replacement Programme (Image: Naval Group).
Recent advancements in lithium-ion battery (LIB) technology have led to a resurgence of conventional diesel-electric submarines. As a result, shipbuilders like Naval Group have opted to move away from air-independent propulsion (AIP) systems and instead focus on a range of submarines equipped with a full LIB configuration.
AIP has served as a reference point for all countries operating non-nuclear submarines for decades. For example, the Netherlands, which operates older diesel-electric submarines equipped with traditional batteries, has long viewed the future adoption of next-generation AIP submarines as the most logical choice for their procurement needs. Recent developments in LIBs, however, have shuffled the deck in the underwater domain, making AIP-equipped submarines a less obvious procurement option.
Air independent propulsion vs full lithium-ion battery configuration
Whether based on fuel cells or Stirling engines, the AIP system provides energy directly to the electric motor that drives the submarine propeller. The
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