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Comment by vel0city | Hacker News Reader

> Southern Spirit connecting the Texas grid for the first time to southeastern U.S. power markets

That doesn't make sense about "first time". Southern Spirit is a new HVDC transmission line (which is awesome and what we need, more please!). There are already Eastern DC grid ties. This would be a good bit bigger (not sure existing ties are even GWs) but I don't understand first. Could someone shed more light on that for me?

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Definitely not the first, surprisingly hard to find clear data about the endpoints of the ties themselves but this random court document has a fairly clear diagram on page 3: https://www.nrg.com/assets/documents/energy-policy/ferc_work...

ERCOT also reports flows for the four existing DC ties: https://www.ercot.com/gridmktinfo/dashboards/dctieflows

With that said the biggest tie is like half a GW, so my guess is that they used the term "power markets"" rather than "power grids" because the current links don't really function as a way to transfer bulk power between markets, even if the Texas grid is technically already connected outwards. Like in an emergency they can import a miniscule amount of power, but nobody's going to be seriously arb'ing power with the existing ties.

The Wikipedia article[3] is not entirely clear and has a shocking failure to cite sources, but it claims the the Texas grid connects to the Eastern grid in two place with DC lines, and has an AC connection that has only been activated once in the Houston area.

What I suspect this is referring to is connecting to the SERC[1] area. I can't find a good source, but I suspect the existing connections are to the MRO[2].

1: https://en.wikipedia.org/wiki/SERC_Reliability_Corporation 2: https://en.wikipedia.org/wiki/Midwest_Reliability_Organizati... 3: https://en.wikipedia.org/wiki/Texas_Interconnection#Ties

The existing active connections are to SPP. The one inactive AC tie is to MISO I believe (which is getting one of the new HVDC ties) and yes these new connections will be to SERC (MISO and SOCO).

That means these new ties will be directly supplying the local grids of about half of the southeastern market which is a first all things considered.

> There are already Eastern DC grid ties.

Strictly speaking there are only three ties into any NERC interconnection. Two of them are ties into SPP. The other is a single AC tie into SERC but it was only briefly activated after Hurricane Ike and hasn't been activated since.

This new project has ties being built directly to both MISO and SOCO which means the texas grid will be connected directly to two of the four main operators of SERC (the southeastern grid/power market).

Ah ok, so I take it the other "East" ties are to MRO and this will be the first to SERC. Thanks for that clarification.

I'm having so much trouble finding details of the existing DC ties. I'd love to know more.

A quick search on ERCOT's website comes up with this doc

https://www.ercot.com/files/docs/2020/07/30/ERCOT_DC_Tie_Ope...

This is great and leading me to answers for lots of questions I have. Thanks!

> That doesn't make sense about "first time".

ERCOT (Texas grid) is famous for operating independently of neighboring grids to avoid federal regulation under FERC.

https://www.utilitydive.com/news/congress-texas-should-rethi...

Failing to actually answer the question posed. And this wouldn't be an interconnection requiring that same kind of federal regulation so pretty irrelevant in the end too. And besides your point is already obvious from the above comments.

But I guess we'll just state random Texas facts now. Did you know the state flower is the Bluebonnet?

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