Electricity Cables *under* SUDS ponds

[Ferdinand]

We have a new outline proposal for a housing estate nearby, and I will be making some comments - supporting principle but pointing out inadequate quality features in the scheme.

 

This is a clip from the "Illustrative Master Plan". We all know how "illustrative plans" proposed at Outline without full compliance, somehow turn into the final plan and the non compliances can get forgotten about at Detailed.

 

1 - Is it normal to bury large 'lecky cables under a Balancing Pond in a housing estate? (These are *big* - they may be 33kV ,and serve thousands of people)?

2 - That looks a little close to the houses, assuming the brown road is about 5m wide.

 

 

The scheme is not dissimilar to another one taken through planning nearby; not sure how the cables ended up there.

 

Edited August 21, 2019 by Ferdinand

[ProDave]

Cables can pass under rivers and streams (the 33KV underground line passes under our burn just upstream under our neighbours garden) so I don't see why not under a pond providing the depth is correct.

 

There are minimum distances for building next to underground lines, I would have to look them up for 33KV but as long as the house is built greater than that distance from the underground line there is no problem.

 

If choosing a house on that development I would be choosing one opposite the underground line, it would quite effectively prevent further houses being added the other side of the road.

[Conor]

It's normal, as long min cover is maintained. If the utility company has an issue, they'll request for the developer to divert the lines (assuming they are existing power cables)

 

[Ferdinand]

Thanks both. Still getting to grips with this. There is a certain amount of nice features that have a look of being designed to be taken out later - eg those nice permeable paths are quite emphasised, yet the people who own the land have not been approached.

 

That is probably normal at Outline, but I have seen other developers salami slice backwards later.

[ProDave]

7 minutes ago, Ferdinand said:

Thanks both. Still getting to grips with this. There is a certain amount of nice features that have a look of being designed to be taken out later - eg those nice permeable paths are quite emphasised, yet the people who own the land have not been approached.

 

That is probably normal at Outline, but I have seen other developers salami slice backwards later.

That sounds strange.

 

While you can apply for PP on land you don't own, that would increase the land value so the owner would then want building plot price for the land, if indeed he agreed to sell.  Normally there is some form of agreement with the land owner before applying for PP.

[Ferdinand]

2 minutes ago, ProDave said:

That sounds strange.

 

While you can apply for PP on land you don't own, that would increase the land value so the owner would then want building plot price for the land, if indeed he agreed to sell.  Normally there is some form of agreement with the land owner before applying for PP.

 

Sorry. No - the people who own the land through which the proposed pedestrian pathways will run have not been approached.

[ToughButterCup]

Walking along the saltings on sea-front just south of Heysham power station I saw a man  way out on the marsh, apparently aimlessly wandering about.  He looked lost, perhaps confused. Given that the tide was coming in, and the areas reputation for suicides I trudged across the marsh to have a chat.

 

He was a botanist, measuring the frequency of a unique and very rare marsh  moth. His theory was that the temperature increase caused by the underlying electricity cable - the supply from the offshore Morecambe Bay Wind Farm - heats the underlying sand sufficiently to drive the moths away.  God knows how big the cable is, but it isn't 10mm. 

 

How much warmer will your cable make the ground above it? Might it drive the Great Crested Newts away? Might it cook a few moths?  Could you fry and egg on the earth above the cable?

 

 

 

 

[SteamyTea]

1 hour ago, AnonymousBosch said:

How much warmer will your cable make the ground above it?

If you know the maximum power of the windfarm, the length, diameter, resistance and specific heat capacity of the cable, then look at the conductance to the round, you should be able to get a figure.

 

[Ed Davies]

Wikipedia lists 5 windfarms in Morecambe Bay, total nameplate capacity 1745 MW. Long-distance HVDC cables have losses of about 3%/1000km. I think it's reasonable to assume that the short cables from the windfarms would have similar orders of magnitude but slightly higher losses, maybe 5%/1000km. If they all come ashore through one cable (which I doubt) the heating at full capacity would be 87.25 W/m. It's hard to imagine a string of incandescent lightbulbs, one every metre, having much effect on the temperature of a salt marsh.

[Pete]

2 hours ago, AnonymousBosch said:

Walking along the saltings on sea-front just south of Heysham power station I saw a man  way out on the marsh, apparently aimlessly wandering about.  He looked lost, perhaps confused. Given that the tide was coming in, and the areas reputation for suicides I trudged across the marsh to have a chat.

 

He was a botanist, measuring the frequency of a unique and very rare marsh  moth. His theory was that the temperature increase caused by the underlying electricity cable - the supply from the offshore Morecambe Bay Wind Farm - heats the underlying sand sufficiently to drive the moths away.  God knows how big the cable is, but it isn't 10mm. 

 

How much warmer will your cable make the ground above it? Might it drive the Great Crested Newts away? Might it cook a few moths?  Could you fry and egg on the earth above the cable?

 

 

 

 

Is this what you get upto on your day off?

[ToughButterCup]

1 hour ago, Ed Davies said:

[...]

If they all come ashore through one cable (which I doubt) the heating at full capacity would be 87.25 W/m. It's hard to imagine a string of incandescent lightbulbs, one every metre, having much effect on the temperature of a salt marsh.

 

Wish you'd been with me Ed: it would have been informative to listen to you both discussing the issue. I might just spend a little time looking to see if he published anything online.

As it was, I thought the guy was one of those lucky people who can become delightfully focused on a tiny, rare something-or-other. And then do something about it.

 

Would that we had more people who cared quite so much, eh?

[SteamyTea]

2 hours ago, Ed Davies said:

full capacity would be 87.25 W/m

 

1 hour ago, AnonymousBosch said:

And then do something about it.

But he probably already assumed that there was something wrong, 

He should have done the heat calculations first, then based on that, looked for evidence.

(he may have, but my experience of dealing with ecology students is that they assume that 'man' will change everything for the worse, and the food chain will always collapse)

[Onoff]

So if the 33kV line heats the ground that much it should heat the lake up a bit.....suggest a ground loop?

[ToughButterCup]

14 minutes ago, SteamyTea said:

[...]

He should have done the heat calculations first, then based on that, looked for evidence.

[...]

 

I do remember our discussion about dependent and independent variables : he knew his stuff. I remember that  just as clearly as the water coming in over my soggy running shoes - the sand and mud stinks out there:  he was working on the saltings a mile or so out from the shore.

He had had the sense to wear boots.