Yeah tunnels underground would be better for superconducting cables, but it is indeed not really a thing as the cooling and installing and maintainance would be waaaay more expensive, than just using higher voltage. Or if one really cares about the loss, use direct current - but we are talking aber very small distances here.

If superconducting would be easy, we likely just would have fusion plants everywhere with no need for transporting electricity long distances.

https://en.wikipedia.org/wiki/London_Power_Tunnels

https://ee.eng.cam.ac.uk/index.php/2025/09/22/from-gridlock-...

An interesting article, I’ll download the IoP report and maybe read it.

But it talks about doing the hard work to improve the Technological Readiness Level from 7 to 9. Although these cables need rare earths so might be problematic.

https://cdn.ca.emap.com/wp-content/uploads/sites/9/2018/04/l...

* Cable thermal expansion under current load: https://www.ahelek.com/news/cable-thermal-expansion-and-its-...

* The amount pictured is in excess of that required for thermal expansion. The excess is to have some spare length in case of modifications. For example if you have to replace the transformer and the terminals are not in the same location. You cannot extend a massive cable like that easily or without degrading its specs.

* The sine wave pattern makes it into AC of course (/s)

I think that's just cables sagging, which is a requirement to accommodate thermal and seismic displacements.

There are many examples of how the UK is London-centric. This isn't one of them.

Cool to see cycling down there - much safer than on the roads above.

1. Cost per kWh transmitted?

2. Cost per person served?

3. Cost per pound of GDP generated?

Please provide this for London and the other locations you have in mind.

https://www.ons.gov.uk/economy/governmentpublicsectorandtaxe...

It’d be super, smashing, great! for the cities to be far better connected together across the Pennines.

And I wish people would understand how costs work.

Pylons need space right, they also need maintenance corridors and access. Every ~360m you need a space to put a pylon[1]. Can you imagine the cost of buying 400m2 every 360 in zone 1?

what about the scaffolding when you need to re-string the cables? can you imagine how expensive that would be? what about if a lorry smacks into it? Its just not practical.

I grew up in norfolk, next to a bunch of HV pylons. No-one commented on them, because they were always there. THey are going to put some more in, and suddenly "its a blot on the land scape" and its "ecological damaging" Then its proposed that the cables are buried. apparently a 200 meter clearing 30km long is more ecologically friendly than pylons ever n hundred meters.

but thats an aside.

[1]https://www.quora.com/What-is-the-distance-between-electrici...

That means the path through the air to some conducting materials needs a certain distance, and that even when wet or iced over or whatever can happen up there.

The cost of oil insulated cables that can do 132kv is about £900 a meter. Whilst there are HV cables that exist on the outskirts of london, they are much rarer in zones 1-3.

I assume that the cost of pylons with raw cables is much much cheaper. The problem is planning permissions, physical clearance. planning permission and now one wants to live near HV cables (that they know of. There are a bunch of 33kv cables buried outside posh people's houses in zone 5, and a bunch in canals.)