Underwater Cable an Alternative to Electrical Towers

[Rhiannon12866]

Generating 20 percent of America’s electricity with wind, as recent studies proposed, would require building up to 22,000 miles of new high-voltage transmission lines. But the huge towers and unsightly tree-cutting that these projects require have provoked intense public opposition.

Recently, though, some companies are finding a remarkably simple answer to that political problem. They are putting power lines under water, in a string of projects that has so far provoked only token opposition from environmentalists and virtually no reaction from the larger public.

“The fish don’t vote,” said Edward M. Stern, president of PowerBridge, a company that built a 65-mile offshore cable from New Jersey to Long Island and is working on two more.

The projects have even drawn cautious enthusiasm from some environmental groups that say the new power lines serve their goal of getting the United States to use more renewable power.

“Environmentalists need to be open-minded to technology improvements, and looking at the big picture,” said Phillip Musegaas, program director for Riverkeeper, a New York environmental group focused on the Hudson River.

http://www.nytimes.com/2010/03/17/business/energy-environment/17power.html?ref=business

[Merchant Marine]

1. I'm wondering if the cold of the ocean floor would help with transmission

I know that you can super-cool a line to make it conduct better, but would the ocean be cold enough?

At least we definitely have the technology for this. Moving electricity across the seabed is way easier than moving oil, the offshore industry has been doing that for years.

[Rhiannon12866]

2. I remember reading about an underwater ocean line awhile ago...

I'm trying to remember what it was used for so I can look it up. It worked just fine, until it needed repair, and fixing it was both difficult and time consuming. :-(

The ocean is probably cold enough, depending where the line is. Using underwater cable would certainly meet with less opposition, unless it affects sea life adversely. Fish may not be able to vote, but advocates for the ocean sure do... ;)

[Kolesar]

5. Could use smaller gauge conductors because the ocean would sink the heat

Of course, this assumes that the designers *want* the additional resistive losses.

[bananas]

3. There's an underwater superconducting cable between Long Island and New Jersey

and underground superconducting cables will increasingly be used on land.
See http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=226387&mesg_id=226411
and http://demopedia.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x234277

In the near term, regular non-superconducting cables will be mostly used,
because we already have a lot of experience with them,
I just want to point out the developing technologies.

[muriel_volestrangler]

12. FWIW, that isn't from New Jersey to Long Island - it's just a 600m section internal to Long Island

in the area of Holbrook and Lake Ronkonkoma (the area, not necessarily the actual lake, I think): http://www.amsc.com/documents/lipa_cable2.pdf

[bananas]

15. Oops, you're right

There's a new HVDC cable between LI and NJ, I must have thought they were talking about the same thing.

http://tdworld.com/underground_transmission_distribution/lipa-neptune-cable-savings/

Neptune Submarine Cable Saved $20 Million for LIPA
Oct 11, 2007 2:26 PM

The Long Island Power Authority saved over $20 million this summer by using the new Neptune electric transmission cable to bring nearly 1.2 million MWh of low-cost power to Long Island during the peak summer season in July, August and September when demand for electricity is highest.

The Neptune cable, which is privately owned and operated and links Long Island directly to Mid-Atlantic power supply resources for the first time, is estimated to save LIPA hundreds of millions of dollars in energy supply costs over the next 20 years.

When coupled with the nearly $200 million in savings by importing lower cost energy via the Cross-Sound Cable since June, 2004, the savings derived by the Neptune cable will help LIPA’s efforts to minimize its power supply costs.

“This historic power project has given Long Island direct access to a lower cost, more diversified power supply in the Pennsylvania, New Jersey and Maryland (PJM) power market that stretches from New Jersey to Illinois,” said LIPA President and CEO Kevin S. Law. “The money saved this summer is significant and in the long term will help us meet our objective of holding down our power supply charges as much as possible.”

The 65-mile long Neptune Regional Transmission System began commercial operations on June 30, 2007. It is an undersea and underground High Voltage Direct Current (HVDC) cable that runs from Sayreville, New Jersey, to New Cassel in the Town of North Hempstead in Nassau County. It can carry 660 MW of power, which is enough to meet the average electric demand of about 600,000 homes.

<snip>

[TexasProgresive]

4. That's fine until some freighter drags anchor

and ruptures the cable. This has been the trouble with submarine telecommunications cables. High tension transmission lines have a whole host of issues to deal with as under sea and in the ground. It is very difficult to prevent leakage to the ground or water when air makes such a cheap alternative.

[kristopher]

6. Is that more or less likely than an suto taking out an elevated transmission line

[TheWraith]

7. Elevated HV transmission lines are pretty robust.

They use large full-steel towers to run those, not regular wooden utility poles. A single car couldn't really take one out.

[TexasProgresive]

8. Maybe it's happened but I don't recall ever hearing of a

transmission line (on steel towers) being knocked out by a car or even a truck. Distribution lines on wood poles is a different matter.

[kristopher]

9. I was making the point that risks to transmission are always present.

Given the number of towers and the number of automobiles (includes all types) it seems likely the issue has presented itself before. The same could be said of the underwater cable idea. They will bury the cable planned for the sand flats of the Eastern OCS, and the general area will be marked on charts.

This is a very good proposal IMO.

[Rhiannon12866]

10. I live in Northern NY where we have rough winters, snow, ice, storms and wind...

My Dad was manager of the utility in this area, so I'm familiar with power outages as the result of downed lines or power poles. However, in the newer developments, like where I live now, the lines are underground so we rarely lose power, even in the worst weather...

[TexasProgresive]

11. Ask your Dad about putting transmission lines underground

These are the high capacity lines that are on large steel towers not lower capacity distribution lines on wooden poles or buried.

That's what is what the OP is suggesting be put under water. I'm no big fan of these things. There are 2 within sight of my house- one on steel towers the other on 60 foot "H" frames made of poles. It would be nice if they weren't there but, Hey, I use electricity and it has to get from the power plants to the grid somehow.

[Rhiannon12866]

19. You're right. My bad.

My point was that putting lines underground or beneath the sea makes more sense, since they're less susceptible to damage. My only concern would be the environmental impact of underwater cables... :shrug:

And my Dad used to talk about the complaints they received about the high tension lines. I remember that farmers complained that they affected the cows... But you're right, we all use electricity. I've experienced enough power outages in my life to realize how tough life can be without it... :-(

[Statistical]

13. Your local low voltage distribution lines are underground.

We put High Voltage long distribution lines in the air for one reason and one reason only.
Air is a great insulator. Earth especially wet earth is very good conductor.

[Kolesar]

14. Capacitive coupling to earth would cause energy losses

And it's gotta be cheaper to place towers on a vacated right of way than to dig trenches. So there are two more reasons.

[Throckmorton]

17. That is the plus for DC transmission lines

No eddy current losses, and no Xc losses. There is a conversion loss, but its not nearly as large as for AC lines, and of course the huge expense for the converter stations at each end. Factoid, for 345 KV 60 Hz transmission systems, 50% of the input power is lost after 400 miles. The charging currents for these lines is staggering.

[Throckmorton]

16. H-Frame towers

That are commonly used are vulnerable to guy-wire damage, more than impacts on the tower bases.

[kristopher]

18. Interesting 'Dymaxion map' of global grid...

http://www.geni.org/globalenergy/library/buckminster_fuller/dymaxion_map/dymaxion_projection.shtml


A New Perception of Earth

World maps are symbolic tools which help to shape our perception of Earth. Every world map projection must make certain compromises as information is transferred from a spherical globe to a flat surface. With this in mind, as early as 1927 Buckminster Fuller, an educator, engineer, architect, author, cartographer and futurist, set out to develop the world's most accurate 2-dimensional world map.

He wanted to provide a view of the whole Earth at once which would have the ability to reveal major trends in world affairs and show the shortest air routes between land masses. Fuller predicted even then that global travel would shift from the sea to the sky and anticipated the emergence of what he termed 'a OneTown Air-Ocean World.'

Designing for Accuracy

Using the some mathematical principles on which his world famous geodesic domes were to be based, Fuller carefully designed a way to display the world all at once, with the least amount of visual distortion. Throughout the next 26 years he refined his world projection through many successive versions in order to reach the highest level of accuracy.

In 1954 Fuller called his final icosahedral projection the 'Dymaxion Air-Ocean World.' (The term 'Dymaxion' was coined in the 1930's from Fuller's most commonly used words: dynamic, maximum and tension.)

In 1980, an even more elegant and accurate Dymaxion Map was developed by Fuller associates Rob Grip and Christopher Kitrick, by using computer-generated algorithms for latitude and longitude information. Now a brand new edition of Fuller's remarkable map, 'The Fuller Projection' has been designed and updated by the Buckminster Fuller Institute using the distinguished cartographic services of R.R. Donnelley & Sons.

[muriel_volestrangler]

20. Going off on a tangent about maps

I was idly googling map projections, and came across some stuff comparing Fuller's projection to an earlier one by a guy called Cahill, from 1909.

http://www.genekeyes.com.nyud.net:8080/1909-Cahill-OT-100mm.jpg

I quite like that - somehow it's more aesthetically pleasing to me than Fuller's straight edges, and it's symmetrical. And, whether by coincidence or not, it has a fair similarity to human expansion over the globe; for instance, New Zealand is separated from Australia, instead being in with the Pacific, but for when and whence people first found it, that's pretty accurate.

And, for a final coincidence, the Global Energy Grid map has a quote from (then-)Senator Al Gore. I found out today what the roughly triangular sections of a map like the Fuller, Cahill or Goode's projection are called: gores (from the name for a triangular section of cloth for a sail, umbrella etc.)

[kristopher]

21. Yes, they are very similar.

The thing I connected the dymaxion map with was an article I read a couple of years ago regarding the use of triangles in 3D rasterizaion for computer graphics. IIRC it was a pretty significant advance that was expected to bring the technology to a state where it compared with filmed images. I have no foundation by which to judge such a claim but I took the map as evidence of the concept.

[eppur_se_muova]

22. Thanks, interesting find. nt