The equipment through which a site takes its power off the grid’s transmission lines. Chapter 4.
From The AI Compute Race. Read the book
Where the book uses it
- Chapter 4 — One Rack
How a datacenter is actually built, from a converted factory in Memphis to a greenfield campus in Texas, and what the clock from first ground to first power really measures.
Where the record uses it
- Campus IREN Sweetwater
- Dated test Chapter 4, permanent power, due 31 December 2026
Sources that use it
- Dominion Energy, Q3 2026 Earnings Conference Call Slide Presentation, 30 October 2026, slide 5 (data center capacity contracted or in process in its Virginia territory at September 2026 about 54.9 GW, of which 12.2 GW under electric service agreements, 9.8 GW under construction letters of authorization and 32.8 GW under engineering letters of authorization, up about 6.3 GW, 13 percent, on December 2025; the first stage, called a Substation Engineering Letter of Authorization on the July deck, is called an Engineering Letter of Authorization here) In the Sources
- Dominion Energy, “Q4 2024 earnings call,” slides, 12 February 2025; Dominion Energy, second-quarter 2026 earnings call slides, 31 July 2026 (“Data center contracted capacity” in Dominion Energy Virginia’s territory: “~40.2 GW” at December 2024, “ESA: 8.8 GW”, “CLOA: 5.2 GW”, “SELOA: 26.2 GW”, slide 18; “~53.8 GW” at July 2026, “ESA: 12.0 GW”, “CLOA: 9.4 GW”, “SELOA: 32.4 GW”, slide 5; the stages as the slides define them: an Electric Service Agreement “Includes revenue requirement whether customer takes service or not”, under a Construction Letter of Authorization the “Customer must reimburse Dominion Energy for all spent costs should they walk away”, and a Substation Engineering Letter of Authorization is a “Detailed engineering plan” with “Costs reimbursed to Dominion Energy”) In the Sources
- Greater Memphis Chamber, “xAI Phase One Substation #63 Providing 150MW of Power to Facility,” press release, 7 May 2025 (the substation energized and 150 MW flowing from 1 May 2025; a second substation, #22, “already in construction”, its completion and connection to the electric grid “planned for the Fall of 2025”). In the Sources
- Frederick County, Maryland, Office of the County Executive, Executive Order No. 05-2026, “Temporary Hold on Accepting, Considering, and Processing Applications for Critical Digital Infrastructure Facilities and Critical Digital Infrastructure Electric Substations,” effective 14 September 2026, signed by Jessica Fitzwater, County Executive, and John K. Peterson, Chief Administrative Officer, and Fitzwater’s letter of 14 September 2026 to Michael Kuykendall of Quantum Maryland, LLC (the order supersedes Executive Order 04-2026 of 1 July 2026, directs the Planning and Permitting Division staff to stop accepting, considering, processing or reviewing the applications, exempts a property with an approved Adequate Public Facilities Ordinance Letter of Understanding “prior to June 17, 2025,” and “shall expire on July 1, 2027”; the letter rejects the company’s application for a Development Rights and Responsibilities Agreement because “the provisions that would have shielded the development from all future local laws are unacceptable”; both read as page images by this book, the scanned PDFs held whole). In the Sources
- Loudoun County, Virginia, “Board Approves Process that Could Pause Legislative Data Center & Substation Applications,” county news, posted 17 September 2026, updated 24 September 2026 (the Board’s vote of 15 September 2026: a resolution that, if approved, “would pause the Board’s action on data center and electrical substation applications that require legislative approval for up to 12 months, the maximum allowed by Virginia law”; “The Board’s vote to consider a resolution follows a legal opinion from the Loudoun County Attorney indicating that a moratorium on data center approvals is not legal.”; “Developers may continue to submit applications to the county”; “the Board’s final votes on data center and substation applications would be paused for one year”; the resolution to be considered “during its October 20, 2026, meeting”). In the Sources
And 4 more: search the Sources.
Related terms
From the glossary of The AI Compute Race.
How to cite this page
Dryburgh, Lee S. “Substation.” In The AI Compute Race. DRYBURGH. https://dryburgh.com/vol1/glossary/substation (accessed 2026-11-01).
BibTeX
@misc{dryburgh-substation-2026,
author = {Dryburgh, Lee S.},
title = {{Substation}},
howpublished = {In \emph{The AI Compute Race}, DRYBURGH},
year = {2026},
url = {https://dryburgh.com/vol1/glossary/substation},
note = {Accessed 2026-11-01}
}