Unique underground power line would send renewable energy from Midwest to Eastern markets

[mahatmakanejeeves]

Business | Technology

Unique underground power line would send renewable energy from Midwest to Eastern markets

Oct. 18, 2021 at 6:00 am

By Mike Hughlett
Star Tribune

The Soo Green Line would be a unique addition to the U.S. electricity grid. Running along a railroad corridor, the big underground power line would ship low-cost renewable energy from the Upper Midwest to Eastern markets. ... Now, if it can only surmount barriers in the power line approval process.

The 350-mile high-voltage direct current (HVDC) line would run from Mason City, Iowa, to a town about 50 miles west of Chicago. The firm behind the $2.5 billion project, Direct Connect Development Co., is based in St. Louis Park, Minnesota, and funded by a global consortium of energy heavyweights.

Soo Green Line has a deal with the Canadian Pacific Railway (successor to the Soo Line Railroad) to host the power line along its right of way, alleviating the biggest problem in plotting transmission lines: resistance from landowners and unwanted environmental impacts.

“Underground transmission makes a tremendous amount of sense for projects that are bigger,” said Joe DeVito, Direct Connect’s president. “The primary issue most people have is the ‘view shed’ — they don’t like to look at it.”

The Soo Green Line has other benefits. As an HVDC line, its “line loss” of electricity due to heat would be less than in a traditional alternating current (AC) power line. And at 525 kilovolts, it would be able to push through considerably more electricity than a standard 345-kilovolt AC line.

{snip}

Mike Hughlett

[Yonnie3]

1. I was wondering the capacity of the line but it was not in article.

I found 2,100 Megawatt stated as the capacity on other websites. https://www.soogreenrr.com/soo-green-transmission-line-will-innovate-energy-transportation/

[mahatmakanejeeves]

2. It's probably in there, and I left it out. I'll go back and add that if I can. Thanks.

{edited}

You're right. The power-handling capacity is not mentioned in the article.

Thanks for the link.

I'm trying to figure out what's so special about Mason City, Iowa, other than that Buddy Holly incident back in 1959.

[Yonnie3]

3. Mason City - Biofuels

google Mason City renewable energy

[Yonnie3]

4. EDIT: I also read that Turner wanted to build a wind farm around there

but no way to connect to the grid. I don't recall where. I was focused on that 2100 MWatts.

Browser history is useful!

The idea for the Soo Green Line sprung from a plan years ago by CNN founder Ted Turner to build a wind farm on his South Dakota property. With no transmission option, Trey Ward, a lawyer working for Turner, developed the idea for a long-distance underground power line.

https://www.seattletimes.com/business/unique-underground-power-line-would-send-renewable-energy-from-midwest-to-eastern-markets/


South Dakota isn't all that near Mason City so it is the concept they are crediting to Trey Ward/Turner

[hunter]

5. Mason City Iowa is on an odd eastern extension of the Southwest Power Pool

Chicago is a western connection to the PJM



https://en.wikipedia.org/wiki/Regional_transmission_organization_%28North_America%29

Using a High Voltage Direct Current (HVDC) line allows long distance transmission on underground or underwater lines (which is not possible with High Voltage Alternating Current lines) and avoids a lot of synchronization issues.

The disadvantage is that you must have expensive AC/DC conversion stations on each end of the HVDC line.

[mahatmakanejeeves]

6. I know you worked on this. Why is HVAC unsuitable for long-distance

Last edited Thu Jun 15, 2023, 07:14 AM - Edit history (1)

underground or underwater lines, when HVDC does not pose a problem?

{edited to add the left-out "not"}

Thanks.

[hunter]

7. Simple explanation: Water and wet earth conduct electricity.

In a buried or underwater HVAC power line the electric current moves from positive to negative at fifty or sixty cycles per second. This creates a fluctuating electromagnetic field that induces electric currents in the water or soil surrounding the line, wasting energy.

The problem isn't so pronounced in cables strung from towers.

HVAC lines on towers can carry power for hundreds of miles with acceptable losses, but just tens of miles underground or under water.

In an HVDC power line the electromagnetic field doesn't fluctuate so long as the power going through the line is constant. Currents that don't fluctuate don't generate electric currents in the surrounding medium.

HVDC lines can carry power for hundreds of miles under ground or under water, and a few thousand miles on towers.

It is of course more complicated than that -- all about resistance, capacitance, inductance, impedance, insulation, inverse square laws, etc. -- but that's the gist of it.

The safety aspects of an underground HVDC line are similar to large high pressure gas lines. There's a lot of potential energy in a fully charged HVDC line. It's not something you'd want to hit with a back hoe.

[mahatmakanejeeves]

8. Thanks. NT