Posts Tagged ‘interconnection’

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Economics for Tres Amigas

October 17, 2009

Michael Giberson

Tres Amigas is a proposed project to link the Eastern Interconnection, Western Interconnection, and the Texas Interconnection (ERCOT) by means of a high-tech three-way superconducting AC-DC-AC connection. You might wonder what economics has to say about such an unprecedented and innovative proposal.

Consider this summary from Ralph Turvey, “Interconnector Economics,” Energy Policy, 34 (2006) 1457–1472:

Interconnectors yield undoubted benefits, but whether their likely level would justify their probable cost is in most cases subject to great uncertainty. Benefits from an existing interconnector could be maximised if a single system operator was responsible for both unit commitment and dispatch in the connected areas. But when there is no such single operator, securing optimal utilisation of an interconnector presents great difficulties, even with a single DC link, as the phenomenon of two-way nominations attests. The vastly more complex problem of achieving an approximation to optimal use of multiple AC links raises additional difficulties….

In the Tres Amigas case we can rule out the idea of “a single system operator responsible for both unit commitment and dispatch in the connected areas.”  Theoretically ideal.  Ain’t gonna happen.

Fortunately, it is possible to approach that ideal by implementation of concepts like “virtual regional dispatch.”  Turns out that VRD has been a tough sell even in cases like New York ISO and ISO New England where it seems to make a lot of sense.  At least the Tres Amigas proposal doesn’t rise to the level of a “vastly more complex problem of … multiple AC links.”  And besides, we don’t need to attain optimal in order to capture a worthwhile amount of gains from trade.

Here’s another related article, Laura Malaguzzi Valeri, “Welfare and competition effects of electricity interconnection between Ireland and Great Britain,” Energy Policy, 37 (2009), Pages 4679-4688. From the abstract:

… Social welfare increases with interconnection, although at a decreasing rate. As the amount of interconnection increases, there are also positive effects on competition in Ireland, the less competitive of the two markets. Finally, it is unlikely that private investors will pay for the optimal amount of interconnection since their returns are significantly smaller than the total social benefit of interconnection.

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FERC is to ERCOT as SPIDER is to ______.

May 6, 2009

Michael Giberson

“Will you step into my parlor?” said the spider to the fly;
“’Tis the prettiest little parlor that ever you did spy.
The way into my parlor is up a winding stair,
And I have many pretty things to show when you are there.”

Jon Wellinghoff, the chief spider at the Federal Energy Regulatory Commission, invited ERCOT to step into the federal parlor. Or, at least, that is what it will sound like to some folks in the ERCOT area.

Actually, Platts reported FERC chairman Wellinghoff was only suggesting that the “Electric Reliability Council of Texas should consider increasing the capacity of ERCOT’s now-minimal interconnects with neighboring grids.”

“If Texas could be more strongly interconnected to the Midwest, forexample, they could integrate even more wind into the system,” Wellinghoff said in a teleconference from Chicago.

“It would be a benefit to them, from that standpoint, and should be something that they ought to consider. Maybe we could still give them an exemption from FERC,” Wellinghoff said, making a reference to ERCOT’s desire to remain largely outside FERC jurisdiction.

Did he say “Maybe we could still give them an exemption”? “Maybe”? Just “maybe”?

Wellinghoff is going to have to be a little more wily if he hopes to get this particular fly into the FERC parlor.

By the way, there are sound economic reasons for strengthening interties between the regions. And whether or not the interties are strenghtened, the rules governing power flows over interties could be made more dynamic and responsive to changing spot prices in the two regions. But for some of the same reasons that federalists applaud states as “laboratories of democracy,” it is useful to have a part of the U.S. power system under somewhat separate regulatory authority. ERCOT can do its own thing to a degree not possible elsewhere in the States, and FERC and the rest of the world can learn from the successes and failures.

However, there is an alternative to strenghtening the interties between ERCOT and the Eastern Interconnection (and banking on the “maybe exemption”), and that is to expand existing transmission lines from the Southwest Power Pool into the wind power rich areas of central west Texas, and allow wind farms in the region to choose between delivering into SPP or into ERCOT.

It is already the case that ERCOT will build power lines into the Panhandle and South Plains portions of Texas, an area long outside of ERCOT and in SPP, in order to encourage wind power resource development in that area.  Another transmission project proposes to reach out from ERCOT to interconnect generation currently linked to the Entergy Texas system in the southeast corner of the state. A few existing generators are connected both to ERCOT and to the Eastern Interconnection.  So this kind of competition around the ERCOT fringes is already happening a tiny bit.

SPP is already planning to add more transmission capability into the Panhandle and South Plains part of Texas.  All the feds would need to do is encourage SPP to add lines a little deeper into the state, and the PUC of Texas should accommodate the effort.  Overlapping transmission capability would make it easier for both systems to accommodate variable wind power output.

The move would enhance wholesale power competition in the region and encourage the development of renewable energy resources, both priorities of the current Commission.

ERCOT may well be wary of too readily accepting the Chairman’s invitation. The fable of the spider and the fly turned out badly in the end, from the fly’s point of view. But there is real value from increasing the ability to trade power between systems, so some sort of deal should be pursued.

(N.B.: When you go into arm’s length negotiation with a spider, always remember it has eight arms.)

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