EMF

[Steven P]

Higher voltage overhead transmission lines are not insulated so don't suffer as much

[Rich Rule]

Far from an expert in these things but I will share this.

 

The area I grew up in the North East had HV cables towards the far end of our estate.  They were horrendously noisy in the damp weather.  I had three school friends who lived almost directly under the cables.  They were at least within 100m of the towers.

 

Of these three families.  My friend had testicular cancer when he was around 18, his father also had cancer.  The kid over the road, his father died of cancer.  My friend Caroline passed away in 2000 from an aggressive for of Leukemia and her brother also had some form of childhood cancer.  Another family friend lost their son at 18 years old.  They lived a few roads away but in the vicinity of the lines.

 

I don't know of the other families in the area but that was enough for me to not want to live anywhere near the cables.  We used to hang out at the youth club which were directly below the lines.  The noise and humming/crackling was really noticeable but we didn't think anything of it.  It was the 80/s after all.

 

But looking back and knowing what I know about the families is enough for me. 

[GarethM]

Always wondered if it was ozone, as the high voltage does create it and it's damaging to health.

 

Had experience with it on aquatics, it literally eats anything organic or plastic.

[Steven P]

Yes, a bit of ozone - imagine each of the crackles like a tiny lightning bolt. In damp and wet weather the resistance of the air is reduced and the electricity can jump between phases - tiny lightning bolts (or sparks, whichever), nothing to worry about but that is what the noise is.

 

 

I wouldn't be living within at least 100m of a pylon either, passing underneath them, the further you are away the more the effects drop off - an inverse square, double the distance and the effect goes down 4 fold. However I have no problem walking or working on or under them.

[nepia]

3 hours ago, Johnsond said:

Educate yourself as I advised. 

I live in Aberdeenshire the North East of Scotland, the links I put up reference SSEs activities in “ The North East of Scotland “ look up “ New  Deer” sub station. 

Regarding the Blyth comment, that town after a long hard period of neglect t is on the  up big time which is nothing but a good thing, as for aesthetics there is a lot more that can and should be done From Lynemouth heading south down the coast to improve things but removing the scars of the areas industrial past ain’t a simple fix. 

 

Some idea of the scale of the construction involved. First pic is, I believe a cable laying boat. In the second cop the orange and yellow people on the roof; the building's 25m tall and sunk 4m into the ground.  Having scraped off as much as possible with machinery more depth was still needed hence the video

[Steven P]

I like the explosion!

 

Grand scheme of things, there are bigger sheds for Amazon

[nepia]

Sheds bigger than 25m tall?!

[Steven P]

Some of the warehouses are huge.. though never stopped to measure them

[openspaceman]

2 hours ago, Steven P said:

Higher voltage overhead transmission lines are not insulated so don't suffer as much

Which is much what I said, there is a big difference between air and seawater.  All transmission lines can be modeled as a pair of wires with resistors and inductors along each wire and capacitors between them in a ladder like formation, with AC there is always reactive power involved and that causes increased I2R losses. HVDC only suffers resistance losses but the cost of the equipment for inverting HVDC to HVAC is much greater and was near enough impossible when the grid was built from 1931 onward. Transformers for stepping up and down AC were well understood (as were the losses). It's 55 years since I studied transmission lines and that was mostly to do with high frequency signals transmission.

 

It's a strange thing but before the gas and electricity grids homes had to manage their own energy requirements, with the economies of scale of fossil fueled generation we became dependent on pipes and cables across the country and into our homes. Now with the advent of cheap PV panels and lithium phosphate batteries a high degree of independence is possible.

[Steven P]

36 minutes ago, openspaceman said:

Which is much what I said, there is a big difference between air and seawater.  All transmission lines can be modeled as a pair of wires with resistors and inductors along each wire and capacitors between them in a ladder like formation, with AC there is always reactive power involved and that causes increased I2R losses. HVDC only suffers resistance losses but the cost of the equipment for inverting HVDC to HVAC is much greater and was near enough impossible when the grid was built from 1931 onward. Transformers for stepping up and down AC were well understood (as were the losses). It's 55 years since I studied transmission lines and that was mostly to do with high frequency signals transmission.

 

It's a strange thing but before the gas and electricity grids homes had to manage their own energy requirements, with the economies of scale of fossil fueled generation we became dependent on pipes and cables across the country and into our homes. Now with the advent of cheap PV panels and lithium phosphate batteries a high degree of independence is possible.

 

 

Likewise a few years (too many possibly) since I was at college, I think your 55 years trump mine here though. Yes, big difference between installation methods, what is actually installed and the power losses in each, and I think we are pretty much saying the same here - my clouded memories and it is quite reassuring that my mind isn't just making stuff up. I wasn't so sure that arborist wanted to go into formulas though - the concepts are good enough? Enough to say in the cable it is more efficient with power losses to go DC, but for the actual kit it is cheaper to go AC. Long distance cables (like Norway to UK) and the equipment costs are a smaller thing than the electrical power losses? Overland going to have to live with transmission towers.

 

 

I think you are right and the grid is working towards a more distributed power generation model - lots of small generation schemes all over the country, interconnected with cabling rather than a few very large power stations - home solar and wind included in the calculations. 

Edited May 28 by Steven P