Ask Lemmy

There are several environmental factors that generally contribute to underground viability.

Ground water- obviously flooding, but evem heavy rain areas, or just high humid soil levels can create problems (cables produce heat, while soil's usually cool so condensation can be a problem wherever theres a splice/ junction)

And speaking of cables producing heat, this can become its own problem. Dirt acts as an insulator for heat. Since the transfer of large amounts of electricity produces heat, unless your ground is cold enough to actively cool them, this means derating the cables (using much larger ones to transfer the same power) which greatly raises the cost.

This is why even in cooler climates, hi voltage / long range transfer is done above ground.

Earthquakes and ground frost difference issues can also cause cables to get sheared.

Ofc, above ground power has plenty of its own issues- trees falling forest fire areas, just general exposure to the elements.

But generally, ease and expense to fix issues, and relative lack of disruption to infrastructure while doing so, win out, Making above ground preferable if there are any potential issues with underground.

Theres also a bit of a political aspect that should be mentioned- who owns the lines- burial is always more costly, so if energy co's own the lines like in america, theyre rarely going to want to spend the extra money burrying and unburrying to fix/ add, unless its really more cost effective. (Or the municipality is footing the bill/ has already done the infrastructure, like a lot of denser urban areas in the US, like NYC and DC. )