Jump to content


Photo
- - - - -

Underwater Suspension Tunnels Prevent Global Warming


  • Please log in to reply
37 replies to this topic

#1 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 05 October 2007 - 06:08 PM

What the heck I'll just post the idea here and see what happens.

----- Original Message -----
From: Stackgenerator
To: EDITED
Sent: Thursday, August 23, 2007 12:14 AM
Subject: TUNNELS REVERSE GLOBAL WARMING AND WEAKEN HURRICANES PRIOR TO LANDFALL!


Judith,
I have this theory I have thought about for years now! I need someone to computer model it! (EDITED) at HRD says I need to get it modeled along with (EDITED)and many other scientists! HRD says they can't model it because they are not funded for it! The Idea involves mixing ocean waters in the Gulfstream using Pascal and Bernoulli principles! The Idea can regulate SSTs anywhere from 72 degrees on up to 90+ degrees if needed! The tunnels basically upwell cooler waters to the surface like a Scoop as (EDITED)once told me long ago! Flow occurs because of the pressure differential between the two openings.Basically, the inlet which I call F1 is > F2 at the tunnel outlet! Pascal says any pressure differential within an enclosed system where energy is conserved a flow will occur! Therefore, Pascal's law can be interpreted as saying that any change in pressure applied at any given point of the fluid is transmitted undiminished throughout the fluid including agai
nst the walls. F1 at depth opposes the flow of the gulfstream while F2 near the surface is faced away from the gulfstream causing this pressure differential! I call this the cooling stage of the tunnels as this will mix the warm surface waters with the cool water exiting the tunnel thus cooling them prior to a hurricanes landfall. Only if a storm is forecast to hit our coastlines will this stage be used to weaken the storm! During cooling stage the tunnels remove 26 trillion BTUs from the SSTs per/day. This now cooler layer of water flows at the rate of 120 miles per day to the North in the gulfstream. In just three days the whole East Coast, GOM states, and Mexico can be offered protection from any hurricane that may hit them! There are three tunnel locations one in the Yucatan Channel, near Key West and just offshore in St. Lucie Fla.! They cover the width of the Gulfstream and Yucatan Current. I keep getting emails like this:


From: EDITED
Sent: Saturday, November 12, 2005 4:40 AM
To: Pat McNulty
Subject: RE: Bernoulli's equation used to modify hurricanes and tornado's



Sounds plausible. Questions I would ask include the cost of construction, cost of maintaining the system, side effects to the local marine environment. Whether it actually would work ought to be tested with some modeling. You could contact Kerry Emanuel at MIT to see what he thinks of the possibility of modeling it to see if it actually works as envisioned.



From: EDITED
Sent: Thursday, December 15, 2005 6:26 AM
To: Pat McNulty
Subject: RE: Pascal's and Bernoulli's principle weakens hurricanes

Pat: I have not had time to run calculations on your idea, but I do
not see an obvious reason why it might not work. The technical issue
would be with the volume of water required. Since you are effectively
mixing heat in ocean columns, you would be warming water at depth in
proportion to the surface cooling, and one should explore the
consequences of this.


As you may imagine, this past season's storms have renewed interest
in hurricane modification and quite a few proposals are being
fielded. I am working with some other faculty at MIT to initiate a
funding program for such proposals as yours; if we succeed I will let
you know and there would then be a mechanism for you to get funding
to work on this.

Yours,
(EDITED)


From: EDITED
>Sent: Saturday, October 22, 2005 6:13 PM
>To: Pat McNulty
>Subject: Re: Scoops( Under water Tunnels)
>Hugh,
>I bet those tunnels are cost effective now???? ANY THOUGHTS?

As I wrote earlier, the loop current is hundreds of kilometers across and its position varies greatly from year to year. What makes the scoops not completely nuts as a proposal is the narrowness and fixed position of the Gulf Stream in the Straits and off Florida's SE coast. In terms of climatology, Greater Miami is the most vulnerable major city in the US. Only Miami has the configuration of a deep "western boundary" current directly offshore. Thus this scheme, if it proves feasible, would work only for Miami and only for Andrew-like storms. The city would remain vulnerable to late season storms, which approach from the SW, like WILMA


hew


----- Original Message -----
> From: EDITED
> To: "Stackgenerator" stackgenerator@cableone.net
> Sent: Monday, October 30, 2006 2:19 PM
> Subject: Re: TUNNEL IDEA??
>
>
> > Unfortunately there is a dearth of models capable of testing
> such a
> > hypothesis. The operational models are coupled to the ocean in
> a 1-D
> > sense eliminating any advection in the ocean. Research models
> are coming
> > along that could be used to look at 3-D interactions, but they
> are so
> > new I am not sure that you could be sure the results was caused
> by the
> > changes you induce or by other issues the new models have not been
> > tested for yet. The big challenge is the ocean modeling (there
> are some
> > good research ocean models, but the issue of forcing in a
> hurricane > environment is not completely understood yet - spray,
> wave breaking,
> > etc), and then the coupling of it to the atmosphere to get the
> > appropriate feedback. We are working on that for the next
> generation > operational models, but it still a work in progress.
> I think in a few
> > years we may have such a tool ready to test your idea in a
> credible
> > manner.


Whew! Were are almost there!

There are two stages for this idea, the one above prior to the emails is just 1/2 the story of the Tunnels! During both stages of operation I have designed them to produce electrical power through a venturi section of the tunnel near the discharge end. All totaled up I have calculated they produce 23 trillion joules of electrical power per /hour during both stages of operation! When not in cooling stage, which is only about 6 % of the time the flow is shunted or bypassed back to the surface where the warm surface water flows through the Tunnels and no cooling occurs!


I know it may sound complex but I hope you can see what I am trying to do with the Tunnels! I think they are the answer to the problem we face with the fossil fuels and Global Warming. Trust me I know it exists I was a control room operator for FPL at the Cutler Ridge Power plant for over 20 years and I am presently in the control room at the Anniston Army Depot in Alabama destroying this countries chemical stockpile of weapons of mass destruction! This is just an idea I came up with when hurricane Andrew rocked my world. It took about five years of thinking everyday. If you have any questions please feel free to get back with me! I also have a blog up about them at Jeff Masters Weatherunderground. If you would like to comment feel free, you are not intruding! Right now I am just having fun with it and kid around a lot. But trust me they are based on sound scientific principle!

My name is Cyclonebuster!

Wunder Blog : Weather Underground

Yours truly,
Patrick McNulty

#2 CraigD

CraigD

    Creating

  • Administrators
  • 7,123 posts

Posted 13 January 2008 - 01:02 PM

I don’t understand precisely what’s being proposed. Specifically, what part of the ocean is being connected to what via the tunnel/tube? Is some sort of hot heat sink (eg: undersea volcanic vent zones) involved?

All totaled up I have calculated they produce 23 trillion joules of electrical power per /hour during both stages of operation!

Perhaps just posting your calculations and notes would answer my questions above.

As far as funding goes, approximate computer modeling is essentially free if you either have programming skills, or can describe the physics of your scheme in a forum frequented by programmers, like hypography.

#3 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 13 January 2008 - 02:04 PM

I don’t understand precisely what’s being proposed. Specifically, what part of the ocean is being connected to what via the tunnel/tube? Is some sort of hot heat sink (eg: undersea volcanic vent zones) involved?Perhaps just posting your calculations and notes would answer my questions above.

As far as funding goes, approximate computer modeling is essentially free if you either have programming skills, or can describe the physics of your scheme in a forum frequented by programmers, like hypography.


Basically what they do is convert the KE of the gulfstream into electrical power. All we need to do is build enogh of them to provide ~12 trillion joules of electrical power! Here are some calculations. They will differ based on how many and the size of the tunnels.
Enough to supply the USA with electrical power many times over! 3.050 Million Megawatts!



Since you need volume to get your answer, I made the assumption that the water is also 100 ft long. Kinetic Energy equals (1/2)m*v^2 so we got .5*299,025,900,000kg*(8.941 m/s)^2 = 149,512,950,000kg*79.941(m^2/s^2) = 11,952,214,735,950 joules.

BTW, thats for the entire 100 ft. So over the 100 ft, your 100 ft tall and 20 mile wide wall of water exerts nearly 12 trillion joules. If you want watts find out how long it took to go that 100 ft in seconds and divide the joules by that time. Then you have joules/second which equals watts. And watts can easily be converted into mega watts.

#4 CraigD

CraigD

    Creating

  • Administrators
  • 7,123 posts

Posted 13 January 2008 - 08:25 PM

Basically what they do is convert the KE of the gulfstream into electrical power.

The Gulf stream, or many other flows of water, can certainly be used as power sources.

A common means to generate power from ocean currents is with water turbines of various kinds, connected to electric generators. The ideal power of such turbines is given by
[math]P = .5 p A V^3[/math]
where: p is the density of the fluid (eg: [math]1000 \,\mbox{kg/m}^3[/math] for fresh water);
A is the area of the cross section of the turbine;
And V is the speed of the fluid.
Well-designed real-world turbines typically generate about 0.3 to 0.5 of this ideal power.
(Source: http://www.cyberiad....aper25apr06.pdf).

This means that, were one to anchor an efficient 10 m wide propeller-like turbine, which sweeps an area of about [math]78 \,\mbox{m}^2[/math] in the surface currents of the Gulf stream, where maximum currents are about 2.5 m/s, it would generate about [math].5 \cdot 78 \cdot 2.5^3 \cdot 0.5 \dot= 300000 \,\mbox{W}[/math]. Given the total US power requirements of all kinds of about [math]3 \times 10^{12} \,\mbox{W}[/math], about 10 million such turbines would have to be anchored in the Gulf stream to satisfy them.

Though promising, there are substantial engineering and economic challenges to such a scheme. The gulf stream is fairly far off shore and in fairly deep water along most of the US east coast, requiring an extensive anchoring structure (cables, etc.) for each turbine, lengthy transmission lines to reach land, and a much increased system of long-distance lines to reach distant inland. The south-flowing California current, is substantially slower, around 0.6 m/s, so would require around 70 times the size and/or number of turbines to supply the power-hungry US west coast, necessitating many trans-continental power transmission lines. Or perhaps other power/energy transport schemes would be more workable.

Ocean current generators would be exposed to difficult conditions, and likely be difficult and expensive to maintain.

Though such a scheme appears at present to be prohibitively expensive, it’s comforting, I think, to note that it’s not particularly technically unfeasible.

Kinetic Energy equals (1/2)m*v^2 so we got .5*299,025,900,000kg*(8.941 m/s)^2 = 149,512,950,000kg*79.941(m^2/s^2) = 11,952,214,735,950 joules.

I’m still unclear precisely what sort of power generating devices you’re describing here, or where you’re getting figures like 8.841 m/s. :QuestionM

Commenting just on the use of units in the preceeding, joules are not units of power, but of energy. They need to be divided by some time interval. For example, for [math]12 \times 10^{12} \,\mbox{J}[/math] to produce a power of 3 million megawatts ([math]3 \times 10^{12} \,\mbox{W}[/math], it would have to be produces ever 4 seconds.

What sort of devices are you describing, and how are they superior to present day water current power generating devices?

#5 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 14 January 2008 - 07:22 AM

What sort of devices are you describing, and how are they superior to present day water current power generating devices?

They are set within the "TUNNEL" in a venturi section where the velocity of the gulfstream is increased to 20 mph at 30 psi. So if you were to make such a tunnel 200 foot tall by 200 feet wide and a hundred foot long, at the narrow venturi section of the tunnel that has an area of 10,000 square feet, the flow of the water should increase to about 20 mph. A 20 mph current with about 30 psi behind it should make a water turbine such as these much more effective rather than just sitting in the open underwater where only a 5 MPH current exists.

The Gulf Stream Turbine - A System to Capture Renewable Energy from Coriolis Currents

#6 CraigD

CraigD

    Creating

  • Administrators
  • 7,123 posts

Posted 19 January 2008 - 12:43 PM

They are set within the "TUNNEL" in a venturi section where the velocity of the gulfstream is increased to 20 mph at 30 psi.

The cyberiad.net paper I link to in post #4, and I think nearly all the literature, calls this a ducted turbine, and notes that, as you suggest, it’s a good way to improve the efficiency of turbines in slower currents, and considerably (by a factor of about 3) improves the efficiency of a turbine in fast currents even when the duct intake area is only slightly larger than the turbine area.

However, efficiency decreases as speed increases, so there’s a limit to how much can be gained by this approach. In addition, turbulence issues become more troublesome as speed increases.

For a large-scale power generator, the trade-off in using a very large duct is one of cost – once the duct and its supporting structure, anchors, etc. becomes more expensive than a similar area of turbines with small ducts, it becomes uneconomical.

Though there appears to be a lot of research on the subject, it looks pretty easy. Rather than computer modeling, one can just build small scale models, and test them in currents of various speeds using a boat. The cyberiad paper has photos of their test barge, a pretty big one, but I think you could use a much smaller boat of the sort that can usually be had for next to free in any lake or costal community.

Distribution appears to me to be a major challenge with hydroelectric power of all sorts, whether the more common dammed river kind, costal/tidal, or ocean current. Basically, the energy to be had from the water is far away from major inland consumers. While a fossil fuel, nuclear, or other land-based power plant can be constructed nearly anywhere, hydro can only be built where a large current is – and, unfortunately, not that many people are present to use the generated electricity, requiring a large power transmission system, which at present means lots of overhead wires.

#7 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 21 January 2008 - 03:37 PM

The cyberiad.net paper I link to in post #4, and I think nearly all the literature, calls this a ducted turbine, and notes that, as you suggest, it’s a good way to improve the efficiency of turbines in slower currents, and considerably (by a factor of about 3) improves the efficiency of a turbine in fast currents even when the duct intake area is only slightly larger than the turbine area.

However, efficiency decreases as speed increases, so there’s a limit to how much can be gained by this approach. In addition, turbulence issues become more troublesome as speed increases.

For a large-scale power generator, the trade-off in using a very large duct is one of cost – once the duct and its supporting structure, anchors, etc. becomes more expensive than a similar area of turbines with small ducts, it becomes uneconomical.

Though there appears to be a lot of research on the subject, it looks pretty easy. Rather than computer modeling, one can just build small scale models, and test them in currents of various speeds using a boat. The cyberiad paper has photos of their test barge, a pretty big one, but I think you could use a much smaller boat of the sort that can usually be had for next to free in any lake or costal community.

Distribution appears to me to be a major challenge with hydroelectric power of all sorts, whether the more common dammed river kind, costal/tidal, or ocean current. Basically, the energy to be had from the water is far away from major inland consumers. While a fossil fuel, nuclear, or other land-based power plant can be constructed nearly anywhere, hydro can only be built where a large current is – and, unfortunately, not that many people are present to use the generated electricity, requiring a large power transmission system, which at present means lots of overhead wires.



Well if you encase the electrical cable in liquid nitrogen the distance you can send it is much further. Near St.Lucie Fla. your in the gulfstream a mile or two off shore. Same for Key West and just a few miles off shore in Miami!
This power can be sent by fiber optic cable and some cables are out there that can carry over a million watts of light energy! This can be converted to electrical power once ashore!

#8 CraigD

CraigD

    Creating

  • Administrators
  • 7,123 posts

Posted 21 January 2008 - 06:57 PM

Well if you encase the electrical cable in liquid nitrogen the distance you can send it is much further.

I’m guessing you’re referring to superconducting power transmission cables. It’s a promising technology, though still limited by the need to use power to refrigerate the liquid nitrogen or other coolant required by present day high-temperature superconducting materials, which must still be kept very cool.

Near St.Lucie Fla. your in the gulfstream a mile or two off shore. Same for Key West and just a few miles off shore in Miami!

Even if tens of kilometers offshore, transmitting power this distance is a minor challenge compared to that of reaching major inland consumers such as, say, greater Chicago, IL, 1300+ km away from the nearest strong ocean current.

None of this is to say that tidal and ocean hydroelectric is not a promising power source, only that the economic and engineering challenges it presents are formidable!

This power can be sent by fiber optic cable and some cables are out there that can carry over a million watts of light energy!

As far as I know, fiber optic cables aren’t used for power transmission lines. Even transoceanic communication fiber optic cables, which I believe are among the most powerful, must be amplified every 50-100 km or so via a power supplied by a conventional aluminum electric conduction, or it’s power loss is so great that its signal can no longer be detected. Most of the fiber optics cables with which I’m familiar are very low power (less than 1 W) communication cables. I’ve seen some higher power (100-200 W) bundles used for illumination, but never a cable in the MW (1,000,000 W) range.

:) Cyclonebuster, do you have an example of such a cable? I wasn’t able to find one with several minutes of googling.

A large single conventional AC power line carries about 1 GW (1,000 MW). Typical loss is less than 5% over distances of several hundred km.

#9 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 22 January 2008 - 05:53 PM

Found this pretty quick and it doesn't have to be the suns light it can also be a laser.

Welcome to IEEE Xplore 2.0: Electricity over glass [fiber optic to transfer electric power]

#10 freeztar

freeztar

    Pondering

  • Members
  • 8,432 posts

Posted 22 January 2008 - 07:30 PM

Found this pretty quick and it doesn't have to be the suns light it can also be a laser.

Welcome to IEEE Xplore 2.0: Electricity over glass [fiber optic to transfer electric power]


Cool! I wonder what the efficiency of such a setup is?

#11 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 22 January 2008 - 09:27 PM

Cool! I wonder what the efficiency of such a setup is?


From what I hear it is more efficent than copper or silver!

#12 freeztar

freeztar

    Pondering

  • Members
  • 8,432 posts

Posted 22 January 2008 - 09:39 PM

From what I hear it is more efficent than copper or silver!


So, from where do you hear this?

#13 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 22 January 2008 - 10:08 PM

So, from where do you hear this?


I will show you in a little bit but this is not the only way to get the power from off shore to on shore. It can also be microwaved.

You can set up transmitters on each tunnel. Then shoot the beam about 40 miles from the furthest tunnel to on shore to receivers.

Wireless energy transfer - Wikipedia, the free encyclopedia

#14 CraigD

CraigD

    Creating

  • Administrators
  • 7,123 posts

Posted 24 January 2008 - 09:40 PM

Found this pretty quick and it doesn't have to be the suns light it can also be a laser.

Welcome to IEEE Xplore 2.0: Electricity over glass [fiber optic to transfer electric power]

Cool! I wonder what the efficiency of such a setup is?

From what I hear it is more efficent than copper or silver!

The linked-to abstract describes a family of products documented here.

According to the documentation, these devices are very low power (less than 1 W per cable, comparable to that of ordinary fiber optic communication devices). Their power output varies considerable with the cable length. At 500 m, it is 0.65 W per channel. An 8 channel device requires 350 W of power. This device’s efficiency, therefore, is about 1.5%. The maximum distance it can transmit power is about 9 km.

These devices are designed for special, low-power application, so don’t represent the efficiency that could be achieved with a device designed for high-power applications. However, according to the JDSU documentation, their efficiency is limited to the efficiency of the photoelectric efficiency of the remote (receiver) unit, so is at best about 50%. This compares poorly to conventional high voltage AC power transmission lines, which average about 93% over the various distances encountered in countries such as the US and UK, usually using aluminum alloy conductors.

Copper and silver have lower resistance than aluminum, but are less used because of their greater cost and mass (which requires larger, stronger towers to support).

I will show you in a little bit but this is not the only way to get the power from off shore to on shore. It can also be microwaved.

Microwave power transmission is indeed a proven technology, with documented large-scale experiments involving the transmission in the multi-kW power range with efficiencies approaching 90%. Though only a design study, this page describes a system intended to transmit 10 kW over a distance of 700 m with an efficiency of 57% in La Reunion island.

A problem with microwave power transmission is that microwaves are absorbed fairly strongly by water, so energy loss in humid air – which is common near the surface of oceans – is significantly greater than in dry air.

Submarine conventional power lines are a proven technology, with typical (90%+) efficiency for short (10 km or less) runs. Where practical, above water power lines (using towers) have significantly greater efficiencies, so would be preferred. I suspect that these technologies would be preferred for the Gulf Stream hydroelectric generators cyclonebuster proposes.

#15 freeztar

freeztar

    Pondering

  • Members
  • 8,432 posts

Posted 24 January 2008 - 10:12 PM

Their power output varies considerable with the cable length. At 500 m, it is 0.65 W per channel.


Uh, that's as far as I had to read into your post to get my answer.

Fortunately for me, I read on and learned more. Great post Craig. :(

#16 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 25 January 2008 - 03:32 PM

The linked-to abstract describes a family of products documented here.

According to the documentation, these devices are very low power (less than 1 W per cable, comparable to that of ordinary fiber optic communication devices). Their power output varies considerable with the cable length. At 500 m, it is 0.65 W per channel. An 8 channel device requires 350 W of power. This device’s efficiency, therefore, is about 1.5%. The maximum distance it can transmit power is about 9 km.

These devices are designed for special, low-power application, so don’t represent the efficiency that could be achieved with a device designed for high-power applications. However, according to the JDSU documentation, their efficiency is limited to the efficiency of the photoelectric efficiency of the remote (receiver) unit, so is at best about 50%. This compares poorly to conventional high voltage AC power transmission lines, which average about 93% over the various distances encountered in countries such as the US and UK, usually using aluminum alloy conductors.

Copper and silver have lower resistance than aluminum, but are less used because of their greater cost and mass (which requires larger, stronger towers to support).Microwave power transmission is indeed a proven technology, with documented large-scale experiments involving the transmission in the multi-kW power range with efficiencies approaching 90%. Though only a design study, this page describes a system intended to transmit 10 kW over a distance of 700 m with an efficiency of 57% in La Reunion island.

A problem with microwave power transmission is that microwaves are absorbed fairly strongly by water, so energy loss in humid air – which is common near the surface of oceans – is significantly greater than in dry air.

Submarine conventional power lines are a proven technology, with typical (90%+) efficiency for short (10 km or less) runs. Where practical, above water power lines (using towers) have significantly greater efficiencies, so would be preferred. I suspect that these technologies would be preferred for the Gulf Stream hydroelectric generators cyclonebuster proposes.


The tunnels can be placed 200 feet from one another much shorter distance than 700m transmitting the microwave beam from tunnel to tunnel. I wonder if wiring them in series or parallell would make a difference??

#17 cyclonebuster

cyclonebuster

    Questioning

  • Members
  • 193 posts

Posted 25 January 2008 - 03:38 PM

Submarine cables for AC
Nelson Island - Texada Island - Vancouver Island (500kV)
Sweden-Bornholm (110kV)
Spain-Morocco (380 kV)
Öresund (380 kV)
Strait of Messina (380kV), replaced overhead line crossing (Pylons of Messina)
Isle of Man to England Interconnector (90kV) - World's longest
New Brunswick - Prince Edward Island(200 MW)
Cebu - Negros, Philippines(138 KV)
Negros - Panay, Philippines(138 KV)
Leyte - Bohol, Philippines(138 KV)

[edit] Submarine cables for DC
Baltic-Cable (between Germany and Sweden)
Basslink (between Victoria, Australia and Tasmania, Australia) (500kV DC) (with a length of 290km underwater)
Cross-Skagerrak (between Norway and Denmark)
Cross Sound Cable (between New York's Long Island and Connecticut, USA)
Estlink (between Estonia and Finland)
Fenno-Skan (Powerline between Sweden and Finland)
HVDC Cross-Channel (Submarine cable between UK and France)
HVDC Gotland (the first commercial HVDC submarine cable installation)
HVDC Hokkaido-Honschu (between Hokkaido and Honshu)
HVDC Inter-Island (Power line between the islands of New Zealand)
HVDC Italy-Corsica-Sardinia (SACOI, Submarine cable link between Italy, Corsica and Sardinia)
HVDC Italy-Greece (between Italy and Greece)
HVDC Leyte - Luzon (between Leyte and Luzon)
HVDC Moyle (between Scotland and Northern Ireland)
HVDC NorNed (between Eemshaven and Fedafjord)
HVDC Vancouver Island (link between Vancouver Island and the Canadian mainland)
Kii Channel HVDC system (through Kii-channel, Japan)
Kontek (between Germany and Denmark)
Konti-Skan (Powerline between Sweden and Denmark)
Swepol (between Poland and Sweden)

[edit] Longest
Basslink (between Victoria, Australia and Tasmania, Australia) (500kV DC) (290km underwater)