New underwater cable

pc1966 · Oct 3, 2021

Just looking at this article:

Full power ahead for UK to Norway under-sea power cable

The 450-mile cable connects Blyth in Northumberland with the Norwegian village of Kvilldal.

www.bbc.com

Trying to work out how they get this bit: "At full 1,400 megawatt capacity it will import enough hydro-power to supply 1.4 million homes, National Grid said"

Are they really saying the assumed average per home is 1kW?

PEG · Oct 3, 2021

No,those numbers stack up....it's 14 kW for one property,which is about right with LED's and hydrogen heating.....and 14 properties with the power off ?

Hunger Games here we come ?

snowhead · Oct 3, 2021

Yes I believe that's the figure the DNOs use as an average.
I did see it published once but haven't managed to find it again.

Dustydazzler · Oct 3, 2021

How long before another country tries to Spur off the cable ?

UNG · Oct 4, 2021

At 450 miles I hope they got the volt drop calcs right

littlespark · Oct 4, 2021

Is this to replace the burned out cable down south?

?

telectrix · Oct 4, 2021

how many Transits will the pikeys need to nick all that cable?

pc1966 · Oct 4, 2021

snowhead said:
Yes I believe that's the figure the DNOs use as an average.
I did see it published once but haven't managed to find it again.

I guess it would be a long-term average equivalent to around £144/month cost.

But it just seems very wrong to claim it covers so many houses as at many times folks will be far over that, cooking, EV charge, etc.

snowhead · Oct 4, 2021

I'm sure the figure used for cable cals for the DNO is around 4amps per house.
So for a group of 25 houses all fed from the same feeder and source the cable would only need to support a load of 100amps.

The DNOs have got years of historic data on actual loads on thier systems.
Even in a group of 25 I bet you'd be lucky to find 1 E.V let alone on charge as well.
Of find more than 1 electric shower in use at exactly the same time

snowhead · Oct 4, 2021

Right, found it, must be because I've had Shredded Wheat for Breakfast.

The best search term is ADMD, After Diversity Max Demand.

This is from Western Power, used for the design of networks for new housing estates;

[ElectriciansForums.net] New underwater cable

And this is a study by Strathclyde Uni on the effects of going all electric.
They were not convinced by the industry published ADMD figures so have used higher ones as a base.
It's surprising how far the existing network can going before it starts to get strained, although it's all averages so some parts of the Network will have reached failure point earlier whilst others, possible older ones where industrial load has been removed, will cope with an even higher demand.

brianmoooore · Oct 4, 2021

UNG said:
At 450 miles I hope they got the volt drop calcs right

450 miles - that's just a short extension lead! How about the losses on this: Tiny Devon village at centre of energy revolution - https://www.devonlive.com/news/devon-news/north-devon-africa-tiny-village-5989455?IYA-reg=704bc3c3-a5be-47f5-8445-fde516a7a9c6

pc1966 · Oct 4, 2021

snowhead said:
I'm sure the figure used for cable cals for the DNO is around 4amps per house.
So for a group of 25 houses all fed from the same feeder and source the cable would only need to support a load of 100amps.

The DNOs have got years of historic data on actual loads on thier systems.
Even in a group of 25 I bet you'd be lucky to find 1 E.V let alone on charge as well.
Of find more than 1 electric shower in use at exactly the same time

I guess that is it, enough properties ad they average out to a low value. Still, it would also be interesting to see how much it varies by day, as I have in my memory a value closer to 5kW/home allowed for sizing substations (eg. 500kVA = 100 homes or thereabouts, not 500 homes).

Zerax · Oct 4, 2021

pc1966 said:
But it just seems very wrong to claim it covers so many houses as at many times folks will be far over that, cooking, EV charge, etc.

I think they use the number of houses figure so that the non-technical general public can understand it... most don't even know that electricity is bought by the kWh !

snowhead · Oct 4, 2021

And going back to the original statement, that would be group of 1.4m homes of average size in an area of average network cabling and equipment.
Not any random 1.4 m homes.

Won't be much good if Norway gets a prolonged dry spell tho.?
They'll be after our Wind generation then.