Even with AIP/Lithium batteries, there are major limitations with a conventional submarine in the Arctic.
A submarine can only go for so far with using the AIP, before the submarine runs out of embarked AIP reactants (liquid oxygen (LOX) and hydrogen). And to the best of my knowledge, there is no submarine tenders nor replenishment ships in the world (? yet ? ) that replenish such. Nominally such replenishment of reactants have to be done at a shore facility (mind you - I could be wrong here).
That means, I believe, in the Arctic, even an AIP/Lithium battery submarine will need to snorkel (or simply surface) and use diesel engines so not to consume too much of the AIP reactants (and save the AIP reactants for under ice or other deliberate under water operation). I made a rough back of the envelope calculation reference AIP/lithium battery range (without using diesel engines) and my calculation suggested a Type-212CD could not patrol the Arctic without spending a fair amount of time snorkeling or on the surface using diesel engines. If it uses the AIP too much, it will consume its AIP reactants too soon.
It did have me pondering other aspects on this ... and how such aspects could lead to new projects or activities needing to be started sooner rather than later, but I have spammed this group a lot with such ... so maybe I should wait a day or two re posting about such.
Good points are being raised that AIP/Lithium battery equipped submarines are limited in any potential Arctic operation. One can only travel so far with an AIP system before its reactants (LOX and hydrogen) run out.
Nominally replenishing such can only be done from a shore facility but even that is not without complications.
My understanding is that naval bases around the world, for navies that currently operate fuel-cell Air-Independent Propulsion (AIP) submarines, do not typically manufacture liquid oxygen (LOX) nor manufacture high-purity hydrogen on-site. Instead, navies buy both of these reactants from commercial gas companies, which deliver them to the naval bases in heavy transport trucks. Liquid oxygen arrives in refrigerated tanker trucks and is either held temporarily in base storage yards or pumped directly into the submarine's internal insulated tanks. Hydrogen gas arrives in high-pressure tube trailers. Because the submarine's storage metal gets extremely hot as it absorbs hydrogen gas, the base hooks up a cooling system that pumps cold water around the external tanks while the hydrogen is being transferred.
I believe this makes the point, that obtaining reactants for a Type-212CD submarines is not something available in every port of call. Just the contrary. This is a complex operation.
As Canada advances the Canadian Patrol Submarine Project (CPSP) to procure up to 12 conventionally powered, AIP equipped submarines—selecting the TKMS Type 212CD design as the preferred baseline—the Royal Canadian Navy (RCN) is likely to face logistical hurdles if sustained Arctic operations of this submarine are desired. Because the production and handling of LOX and hydrogen typically require specialized infrastructure that does not currently exist at any Canadian naval facilities — and given the lack of northern facilities capable of any Canadian naval support, evaluating mobile, forward-deployed reactant generation for a Type-212CD represents one potential operational concept worth considering.
One technical approach to examine is the integration of commercial containerized, sea-going reactant generation modules aboard future RCN auxiliary platforms, such as the
Protecteur-class Joint Support Ships (JSS) or even into the design of future concept ships such as G-LAAM. Utilizing standard 20-foot or 40-foot ISO container footprints, modern water-electrolysis units, hydrogen and cryogenic air-separation units (for LOX) could theoretically be powered by a supply ship’s electrical grid and fed by its fresh-water desalination capacity. If this is proven to be viable, and if such commercial containerized modules are available, then embarking modular processing plants on an auxiliary vessel may establish an ocean-going replenishment capability for AIP, with reactants directly created on the mobile base ship or supply ship.
Evaluating this as a potential inclusion in an Arctic mobile base ship would also allow the RCN to assess the feasibility of resupplying AIP submarines in remote regions—such as the Arctic, or distant Indo-Pacific sectors—without relying on shore-based industrial gas infrastructure. Given the multi-year timelines required to study, possibly test, and integrate shipboard reactant systems into either new supply/G-LAAM ship design, or into existing ship refit planning, means early technical assessments would be necessary to determine the viability, cost, and most important, the safety implications of such an approach.
Obviously (again – like a number of my posts) there is truly massive amounts of speculation in the above.