Science that makes you cringe

[Cudzoziemiec]

I think DC transmission is used in Siberia and Russia's Far East, due to the enormous distances.

And according to that Wikipedia, Britain is Europe's nexus of HVDC transmission, albeit not overhead:

https://en.wikipedia.org/wiki/High-voltage_direct_current

[Kim]

The economics shift further in DC's favour as soon as the medium you're stringing the cables through is water, rather than air, as the losses from AC become greater.

[Mr Larrington]

There's quite a lot of it about, it seems: https://en.wikipedia.org/wiki/List_of_HVDC_projects

[Kim]

And according to that Wikipedia, Britain is Europe's nexus of HVDC transmission, albeit not overhead:

https://en.wikipedia.org/wiki/High-voltage_direct_current

It makes a lot of sense to trade electrons with BRITIAN, on account of us having our own timezone, and (for viewers in Scotland) an occasional surplus of wind power.  Thanks to Putin, it's recently made economic sense to off-load LNG here, burn the gas and sell the resulting electrons to Europe, where there's been a shortage of gas terminal capacity.

IIRC the North Sea Link paid for itself in about a year.

[mrcharly-YHT]

The economics shift further in DC's favour as soon as the medium you're stringing the cables through is water, rather than air, as the losses from AC become greater.

That's something I hadn't heard.

Some dielectric effect coupling with the water?

There is a rumbling of concern about the effect of electric cables on sealife.

They've found that crabs are reluctant to cross the HVDC cables, which is an issue when the crabs migrate for breeding.

[Kim]

The economics shift further in DC's favour as soon as the medium you're stringing the cables through is water, rather than air, as the losses from AC become greater.

That's something I hadn't heard.

Some dielectric effect coupling with the water?

I think it's more that a rugged cable (rather than an uninsulated wire strung from pylons) is in itself a fairly effective capacitor.

There is a rumbling of concern about the effect of electric cables on sealife.

As featured in the documentary Jaws 2   

They've found that crabs are reluctant to cross the HVDC cables, which is an issue when the crabs migrate for breeding.

That's not going to end well.  Never underestimate crabs.

Presumably burying the cables would mitigate that, but that's a whole lot more expense...

[Cudzoziemiec]

I think burying the cables would be not only a whole lot more expense, it would introduce an whole extra level of sea-bed disturbance. Something similar is being observed in some places with buried (in land) cables and pipes.

[Tim Hall]

More electrically based nonsense:

The specialist global investment manager revealed the Kent-based project, which consists of 373MW of solar and “more than” 150MW of battery energy storage, is expected to be fully completed by the end of 2024.

My bold.

That from a solar power trade comic, where you might hope they know the difference between MW and MWh. I guess it's a regurgitated PR piece that was written by someone who doesn't.

(Ob. Cycling: The Whitstable FNRTTC goes past it.)

[ElyDave]

I think burying the cables would be not only a whole lot more expense, it would introduce an whole extra level of sea-bed disturbance. Something similar is being observed in some places with buried (in land) cables and pipes.

Pipelines are generally trenched and protected against overtrawling. I'd have assumed the same kind of protection for cables

[Kim]

More electrically based nonsense:

The specialist global investment manager revealed the Kent-based project, which consists of 373MW of solar and “more than” 150MW of battery energy storage, is expected to be fully completed by the end of 2024.

My bold.

That from a solar power trade comic, where you might hope they know the difference between MW and MWh. I guess it's a regurgitated PR piece that was written by someone who doesn't.

The clue's in the first part of the sentence (my bold).

[mrcharly-YHT]

I think burying the cables would be not only a whole lot more expense, it would introduce an whole extra level of sea-bed disturbance. Something similar is being observed in some places with buried (in land) cables and pipes.

Pipelines are generally trenched and protected against overtrawling. I'd have assumed the same kind of protection for cables

You'd assume wrong.

seabed Power cables are just draped on the seabed. Very vulnerable to anchors and beam trawling.

Hence why Lewis lost its interconnect a couple of years back.

[LittleWheelsandBig]

There are different environmental consequences to breaking cables and oil pipelines, hence protection or not.

[Tim Hall]

More electrically based nonsense:

The specialist global investment manager revealed the Kent-based project, which consists of 373MW of solar and “more than” 150MW of battery energy storage, is expected to be fully completed by the end of 2024.

My bold.

That from a solar power trade comic, where you might hope they know the difference between MW and MWh. I guess it's a regurgitated PR piece that was written by someone who doesn't.

The clue's in the first part of the sentence (my bold).

GPWM

[ElyDave]

I think burying the cables would be not only a whole lot more expense, it would introduce an whole extra level of sea-bed disturbance. Something similar is being observed in some places with buried (in land) cables and pipes.

Pipelines are generally trenched and protected against overtrawling. I'd have assumed the same kind of protection for cables

You'd assume wrong.

seabed Power cables are just draped on the seabed. Very vulnerable to anchors and beam trawling.

Hence why Lewis lost its interconnect a couple of years back.

Every day's a schoolday

[rafletcher]

See also trans-oceanic data and communications cables, and the keenness of the RN to keep Russian vessels at bay.

[mrcharly-YHT]

they don't just lay them in a straight line, shorestation to shorestation, but do a detailed seabed survey, trying to avoid draping the cable over seamounts, or sudden crevasses, etc. A nice soft bottom is preferred, to avoid damage from being sawed back and forth by currents.

[ElyDave]

Pipelines may have a concrete coat to stop them floating as well (gas ones definitely), and are then gently puddled into the silt by a couple of meters using a water jet as I understand it.  They may also have rocks dumped along the line as trawl protection at certain points, or even artificial rock "mattresses" where there are exposed sections.  Anything like a junction or a valve that sticks up tends to have a large structural protection.

I'm slightly mind boggled that we don't even shallow-bury the cables.

[Mr Larrington]

There's a whole appendix to the e-book edition of Neal Stephenson's “Cryptonomicon” dedicated to the subject of international telecommunications cables.

[Giraffe]

Article about moving bagged waste along 'vacuum' tubes said that the bags were moved by negative pressure.

[hellymedic]

Article about moving bagged waste along 'vacuum' tubes said that the bags were moved by negative pressure.

Sub-atmospheric pressure is known as negative pressure in medical & other jargon.

[Kim]

I don't think it's wrong to refer to gauge pressure (which is clearly what they mean in this context) as negative.  Absolute pressure would be another matter.

[Feanor]

There's a whole appendix to the e-book edition of Neal Stephenson's “Cryptonomicon” dedicated to the subject of international telecommunications cables.

Ah, that's not in the Dead Tree version which I recently finished.

There is, however, a detailed discussion of the Solitaire Cipher by Bruce Schneier, the original author of the cypher.
Stephenson actually had Schneier invent this playing-card based cypher just for the book!
It's a cipher designed to be performed by hand, and required nothing more incriminating than an ordered deck of playing cards.
In the event the Secret Police come to the door, you simply shuffle the deck and the key is destroyed.

In the book, it is referred to as Pontifex.

[Mr Larrington]

And early editions contained an error in the Perl script.  Easily done give its resemblance to line noise.

[Giraffe]

I don't think it's wrong to refer to gauge pressure (which is clearly what they mean in this context) as negative.  Absolute pressure would be another matter.

Indeed - so say so.

[mrcharly-YHT]

Article about moving bagged waste along 'vacuum' tubes said that the bags were moved by negative pressure.

this grinds my gears.
'Vacuums don't suck' is something I'd like taught in all schools.

Regardless of the use of negative, the bags are definitely not moved by negative pressure, but by a pressure differential. In lots of situations, they are moved by the weight of the atmosphere.