Fibre needs bigger bend radii proportional to the cable size, but they’re still rarely over 15mm diameter cables so you can bend them in like 150mm.

Once you start getting to 11kV MV cables, they do like 2m bend radii.

Yeah, directional thrusting is a thing. It was used a lot when contractors were installing NZ’s new fibre network about a decade ago. I don’t think it’s in as widespread usage for power because power cables tend to have much wider bending radii.

Regular trains don’t run underground. Lots of opencast mines exist .

Basically all mines have an above ground terminal where whatever you mined is unloaded from your underground trains, lifts, haul trucks or whatever else onto storage piles, then loaded onto the actual long distance trains.

If the mine entry is up a mountain, then the trip down from that point will be a net energy producer regardless of anything else.

Two religions is not more statistically significant than one.

Referring to yourself in the third person and acting like this comes off as extremely condescending.

I wouldn’t be surprised if there are electrified railway lines doing the same. Regenerate large amounts of energy into the grid while descending loaded; consume a relatively small amount of energy to haul the empty train back uphill.

If you’re thinking of that CGI crane lifting concrete blocks, it’s unfortunately a really bad idea.

Pumped hydro stores energy by lifting weight uphill, instead. Water is basically the cheapest thing you can get per tonne, and is easy to contain and move.

To store useful amounts of energy using gravity, you need pretty large elevation differences and millions of tonnes of mass to move.

I expect structural life of the tunnels isn’t much longer than the services within them, especially with roads above.

Boring through rock is super slow and expensive, plus now your tunnel needs to be big enough to walk & run machines through, and needs aircon to keep it cool. It is done, but usually only in CBD areas where you need lots of cables and room for future expansion. Google ‘cable tunnel’ and you’ll find lots of examples. Trenching machines go through very expensive consumable digging teeth whereas bucket trucks are just a fancy forklift, burning fuel and needing hydraulic & engine maintenance.

With high voltage cables, the (really thick) insulation gets really expensive, plus you need more conductor (copper/aluminium) because the insulation needs to stay cool. Aerial lines are directly air cooled (better cooling), and can run hotter, because the limit is the metal getting too hot and sagging, not the plastic degrading. Glass insulators are only needed at every tower and can be easily replaced.

Because keeping the conductor small is important, you need to use expensive copper rather than cheap aluminium for cables.

You also need regular joints which are very labour intensive, because they have to be perfect and you can’t make a cable the full length because you can’t ship a drum that big.

If a cable fails, fixing it is much harder than fixing an aerial issue. There was a cable fault in LA in 1989 that took 8 months of round-the-clock work to fix. When a tower falls over (usually because of slope failure or undermining), temporary structures are usually up in a couple of days.

Digging trenches under roads is much more invasive than pulling cables over roads, and rivers are even worse to deal with. It’s very common for underground cables to be converted to overhead when they cross a river before heading back underground.

The Western HVDC Link between Scotland and England was built as an undersea cable because it’s so hard to get planning permission and land rights to do major projects in the UK, as High Speed 2 found out.

Yeah, we have lots of underground services here in NZ. It’s when you start getting to low population densities that you start having trouble doing it.

Plenty of cities have ‘steam tunnels’ used for far more than just steam pipes, and sometimes no steam in there at all. It’s an awesome solution where you have reasonable density, and especially for within a facility/campus.

I don’t think you’re going to see it happen in surburban streets. It’s the tyranny of the car.

I can’t find the exact shot, but I used to have a picture of the 220kV lines parallel to the Desert Road as my desktop background. Something like this:https://johnmathews.smugmug.com/Nov-18-Desert-Road-North-Island/i-CkSm5tK

Underground works well for greenfields construction, where you can map everything out ahead of time and don’t have to deal with existing underground services.

It’s manageable on low-density streets where its really only three waters and maybe some telephone lines.

It’s a nightmare to underground existing infrastructure in dense environments. Underground is already full of three generations of critical comms, corroding gas, water, HV lines that will fail if you look at them wrong, and if you’re really unlucky, steam pipes too.

Still about a 10x cost difference, plus (particularly on transmission lines) there’s issues with extra capacitive loading.

Oh, I mixed up your post. Sorry.

If you’re considering the US federal government (excluding the newly elected carrot…) ‘tyrannical’, what civilisations are you considering not tyrannical? The list has to be very, very small.

None of the definitions of tyranny I see have a restriction on scale. You can be a tyrant ruling a hundred people or a billion. It’s technology (transport, food storage, writing/communication) and geography that limit the size of a tyranny. I’d argue lots of small tribal societies wander into tyranny; it’s just hard to rule over multiple islands when you don’t have writing or metals.

There’s religions in Asia other than Buddhism.

There was rampant cannibalism in Polynesia along with all kinds of infighting. Maori gods have plenty of murder and war in the mythology.

War in Asia goes far wider than just one empire. Imperial Japan were thoroughly tyrannical during WW2, as well as many other conflicts.

Any civilisation that could spare, mobilise, and feed enough people to form an army basically did so, sooner or later. It’s a supply lines and population problem. Small populations can’t raise large armies and send them long distances.

25kV railway electrification is normally very separate from local electric grids.

Grid ‘reliability’ issues are normally load shedding or damage at the distribution level; the 10-22kV local networks. DC networks like third rail and 1500V are often supplied from local substations.

Long distance 25kV lines are almost always fed directly from big substations on the grid backbone - here in NZ, they’re all from the 220kV substations at roughly 140km spacing; I believe in the UK it’s almost all from 400kV subs. Those are extremely reliable and well monitored because no-one wants to be doing a grid black start, and loss of a grid backbone substation gives you a pretty good chance of the whole grid falling over. 25kV railway electrification is rock solid.

NZ’s grid is roughly 93% efficient; half of that is in the transmission (long-distance) and the other half in distribution. We have one of the worst grid layouts for transmission efficiency because most of the generation is in the deep south while the load is in the north, with an underwater section in between.

Batteries and charging is IIRC around 90% efficient, round trip. Call it 75% from generator terminals to motor terminals.

If you’re not generating the hydrogen right at the generator, you’ll also be incurring grid losses to get the power to the hydrogen plant.

If you are generating hydrogen at the generators, you’ll then need to transport the hydrogen even further. I’m struggling to find exact figures for losses in natural gas networks, but my understanding is that leakage is several percent. Any large-scale hydrogen system could end up being similar, plus you now need a shipping industry to move the hydrogen to the point of consumption.

New Zealand is famously a very old country.

Hydrogen has a major efficiency problem. Unless the electricity to create the hydrogen is practically free (i.e. grid price is zero, you’re turning off generators) it’s not worth it. You’re at like 30% round trip efficiency whereas batteries and overhead lines are well above 90%.

Using hydrogen also prevents regenerative braking, which is one of the big advantages of battery or overhead electric.