Thinking outside the box a bit I think there could be lots of applications for “long extension cords”. Especially when you consider how light and thin a cord could be when you use high voltage.
I recently replaced my mower with an old push mower [1], someone local restores them and sells them for a reasonable price (much less than anything new or even a petrol or electric second hand mower.
It works so well I wouldn't go back unless I had more than about 200 sqm to mow. Modern push mowers are junk and put me off in the past, but the older ones are much heavier and better built. They cut grass cleaner than a rotary mower which is supposedly better for the grass too.
[1]: trademe.tmcdn.co.nz/photoserver/full/1857940265.jpg
They really really are in NZ at least. I saw some at Mitre10 the other day and they were pretty much all plastic, wtf?
Someone local to me as well buys second hand mowers and fixes em up, puts a better motor on etc. Works well - been a very long time since I've touched an old push mower though!
My old man runs a landscaping/gardening/mowing business so I grew up helping mow lawns etc and you're quite right they've just gotten so bad. We'd buy those commercial ones, and over the years they just got bigger, heavier and shittier - breaking all the time. Dad went back to using just basic older mowers and they work just as well.
You're correct that those old push mowers are better for the grass if you don't have the catcher on - which is the reason for some mowers having that "mulch" function (spitting cut up grass back out without a catcher).
Ok, now I'm wondering how much one can decrease the weight of a rocket if it starts plugged to some cable.
Any ISP gain at the beginning of the trip helps decreasing a lot of weight, but cables weight something too, and 1km or 2 of cable falling vertically is a hell of a hazard...
Is it possible to have a 10KV x 100A power tether snaking around like this ?
There is a whole basket of safety requirements which kick in with higher power scenarios
And in mining they run portable medium voltage wiring through the tunnels to baby substations. They even make plugs and sockets rated to 15kV or possibly to 35kV, the upper limit for "medium voltage" in NA.
Obviously you aren't going around plugging these cables in like they're attached to a reading lamp. They are on disconnects or circuit breakers and the circuit is de-energized before connection or disconnection. Otherwise arcing would destroy the connector. A faulted circuit would cause an explosion on connection likely killing or severely injuring an operator.
Electricians working on medium voltage circuits must have medium voltage training and certifications.
To extend that to extension cords -- if your boat/tool or whatever needs 5kw of power, at household voltage of 120v, you'd need a #4 wire which weighs 1.3 lbs/10 ft. At 240V, you'd need a #10 wire which weighs 0.3 lbs/10 ft. At 360v, only a #14 wire which weighs 0.13 lbs/10 ft.
So by tripling the voltage, you can cut down the weight of the cable by roughly 10x.
It turns out that our insulators are much more efficient than our conductors, so the trade-off is a non-brainier up to extremely high voltages.