> Known as ocean thermal energy conversion or ‘OTEC,’ the technology was first invented in 1881 by French physicist Jacques Arsene d’Arsonval. He discovered that the temperature difference between sun-warmed surface water and the cold depths of the ocean could be harnessed to generate electricity. [...]

> For OTEC to work it requires a temperature difference between hot and cold water of around 20 degrees Celsius. This can only be found in the tropics, which is not a problem in itself.

How much of a thermal gradient is there with submerged polar datacenters?

IIUC it is possible to tube solid-state thermoelectric devices to certain ranges?

What's the thermal gradient between a crawlspace or a subterranean basement and an attic under a dark roof?

OTEC: Ocean thermal energy conversion: https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversio...