"A 385 km subsea power cable, billed as one of the world's largest, has
come ashore in the UK this week"
"The cable reached shore at Ardneil Bay in North Ayrshire, Scotland as
part of the £1bn ($1.25bn) Western Link HVDC project, which aims to
transfer renewable power from Scotland's transmission network to
consumption centres in England and Wales"
With the closure of Longannet and the forthcoming closure of Scottish
nukes, I wonder if the current flow is going to stay one-way.
(='.'=) systemd: the Linux version of Windows 10
On Tue, 24 Jan 2017 08:23:22 +0000, Mike Tomlinson
The project website says it's a 2.2GW capacity cable, which should
draw down a lot more of the surplus wind power from Scotland, and save
National Grid (and us) from paying the wind generators not to generate
when there's more than the existing England - Scotland links can
carry, so bringing the maximum capacity to 5.5GW, up from the 3.3GW
estimated from the Mearns link you give.
On Tue, 24 Jan 2017 13:18:44 +0000, The Natural Philosopher
Hmm... in 2015 we paid £90 million in constraint payments to UK wind
generators not to generate (Figure 7 in Mearns' blog on the topic:
http://euanmearns.com/uk-wind-constraint-payments/ ). The Western Link
is going to cost £1 billion. Plotting Mearns' data for 2012 - 2015,
and assuming a quadratic increase in payments year by year (which may
not be the case), means that we will have paid out a little over £1
billion in total in constraint payments by 2019. Even if we just
continue to pay constraints at about £100 million per year, we will
have paid for the Link in ten years.
On that basis I would say the Link is value for money.
There is 3.5GW of England & Wales to Scottish border transfer, this is not a
single interconnector and is the current combined five feeder (4 x 400kV & 1 x
132kV) thermal limit, that is public knowledge to anyone who really needs to
This limit will increase to 4.4GW with current and ongoing transmission
upgrades onshore, then to 6.6GW with the Western HVDC Link
and ultimately to around 8GW by 2025 with further onshore transmission upgrades
and the Eastern HVDC Link.
On Wed, 25 Jan 2017 13:19:35 +0000, The Other Mike
Interesting. Thanks. OOI does the 4 x 400kV feeder constitute four
separate power lines, with pylons etc, or is it a single set of pylons
strung with groups of four cables separated by spacers as in this pic
http://tinyurl.com/gqrvhbn ? And what do they do to upgrade such a
line; more cables, thicker cables or what?
That's a 475kV tower, there is 3 phases each side and they run in
parallel for resilience. All power lines above 33kV run two parallel
supplies but the 33kV and 66V on wooden poles may be separated by ~50
You mean because of increased risk?
Trees/branches are all categorised depending on distance from
conductors , voltage of conductor and what bits might fall on
conductor. Any that are too dangerous to be worked on live require a
One pylon like that is two feeders, almost always operating at the same voltage,
and if the image title is correct that'll be 400kV as is everything along the
Some have operated at 400kV on one side and 275kV on the other, but built with
400kV insulators and clearances. That was the case for around 20 years with the
pylons strung alongside the A74 / M74 or whatever they are calling the road from
Carlisle to Glasgow these days.
Each cluster of four conductors is one phase and historically most 400kV and
275kV lines were strung in that manner. Upgrading can be done with four
conductors of a higher specification but since the mid 1990's double and more
recently triple conductors can be used. The physical cross sectional area is
not necessarily increased so there is the benefit of reduced wind loading with
the advantages of significantly higher current ratings.
On Thu, 26 Jan 2017 19:23:35 +0000, The Natural Philosopher
In my post earlier in this thread, I cast doubt on your suggestion
that it would be cheaper to pay them not to generate. If the Eastern
link is going to cost the same as the Western link, say another
billion, to which is added another great chunk of cash for upgrading
the overland links down the middle, then I think you were right!
One billion quid for an asset with a 60-75 year life, that can transfer around
650 million quids worth of electricity (assuming £35/MWh) per annum is fantastic
value for money if you look at the wider picture.
It very significantly increases grid resilience in a number of areas, all but
eliminates constraint payments North of the border, which it should be noted are
consistently and significant higher in monetary value across the UK for gas
fired generation than they are for 'renewables' and it also enables the future
UK-Norway interconnector to operate without constraint.
While the Eastern HVDC link may also be deemed 'expensive' being of a similar
cost the onshore transmission system improvements are considerably cheaper as
much of the work is simply conductor restringing.
Grid upgrades and expansion are, by their very nature, examples of proper well
thought out long term infrastructure thinking, something sadly absent from much
of the UK and Europe.
Well let's say at cost of capital 7.5%, lifetime 70 years, O & M 5%,
that cable needs to generate £139m a year just to break even.
The opportunity cost is between paying ~£2bn for the renewable
electricity because it doesn't cost £35/MWh. Its AT LEAST £100/MWh...
plus £139m, to get it to the UK, where it will offset a mere billion of
fossil energy that doesn't have to have a grid surcharge slapped on top..
versus paying the ~2bn to not generate the electricity, and not paying
the £139m. But instead paying a £650m to get some reliable fossil
Well its marginally worthwhile, except that of course the electricity is
NOT going to fully utilise that grid link is it Only about 20% of the
electricity it COULD take WILL be taken because the rest of the time the
wi9ndymills aren't spinning.
So that means it has to charge £139m for £200m worth of juice: way more
expensive than locally sourced gas
Which is why its cheaper in times of high wind to pay the scottish
windfarms (and gas sets) not to generate.
If you think it will ever be built..
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
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