Burial Is Proven Elsewhere as Virginia Debates Dominion’s Line

RICHMOND — Dominion’s underground HVDC pitch into Northern Virginia did not invent the technology. Packet materials show PJM studied burying part of the old PATH corridor as early as 2009 — and that fully buried or mostly buried HVDC projects are already under construction or advancing from New York to Iowa while Virginia’s Democrat-approved data center load forces a choice between more overhead steel and cables in the ground.

At a October 22, 2009 TEAC meeting, PJM presented a PATH HVDC Conceptual Study for the Potomac-Appalachian Transmission Highline — then planned as a 765 kV AC line from Amos to Kemptown. Black & Veatch with ABB compared staying with AC overhead against two HVDC concepts. Concept 1 was HVDC overhead Amos–Welton Spring–Kemptown. Concept 2 kept 765 kV AC overhead Amos–Welton Spring and switched Welton Spring–Kemptown to HVDC underground. Physical tradeoffs were stark: AC overhead used a 200-foot ROW and structures up to about 130 feet high and 150 feet wide; HVDC overhead narrowed ROW to about 150 feet; the underground HVDC segment in Concept 2 cut Welton Spring–Kemptown ROW to about 110 feet. Cost did not shrink with the corridor. Current AC design totaled about $1.767 billion. Concept 1 HVDC overhead rose to about $2.411 billion. Concept 2 with VSC converter stations and underground HVDC jumped to about $3.595 billion — roughly double the AC baseline. PATH later died; the cost lesson did not.

Elsewhere, burial moved from study decks to dirt. Champlain Hudson Power Express — CHPE — is repeatedly cited as the country’s largest fully buried (and submarine) transmission project: roughly 339–340 miles from Quebec to Queens, about 1,250 MW, multi-billion-dollar capital (reports in the packet cite roughly $4.5–$6 billion depending on scope and year), with roughly 140 miles underground along highway and rail corridors and nearly 190 miles under Lake Champlain and the Hudson system. New York approved the line to deliver Canadian hydro and help retire peaker plants under the state’s climate statute; construction advanced toward mid-decade in-service targets.

National Grid’s Twin States Clean Energy Link sketches a hybrid: about $2 billion, 1,200 MW bidirectional between Quebec and Londonderry, N.H., with upgrades to existing AC overhead plus about 50 miles of new underground along Vermont highways and 25 miles in New Hampshire. Developers said Northern Pass and Maine’s Clean Energy Connect taught them that major tree-clearing for overhead corridors would not fly. Cross-linked polyethylene cables in concrete-encased conduits under roadways — with HDD under rivers — became the design language. Northern Pass itself had already switched toward “HVDC Light” XLPE technology to bury 52 miles through sensitive New Hampshire terrain, cutting capacity from 1,200 to 1,000 MW so two cables could replace six; Eversource then told the public overhead ran about $3 million a mile versus $8–$13 million underground.

SOO Green’s 525 kV HVDC link — about 350 miles underground beside railroad ROW from Mason City, Iowa, to Yorkville, Illinois — won Iowa Utilities Board franchise approval in September 2023 for roughly 2,100 MW of MISO–PJM transfer capability, with commercial operation targeted around mid-2029 pending interconnection agreements. S&P Global reporting the same season noted merchant developers filling the void in U.S. interregional HVDC while Europe deployed tens of gigawatts of modern HVDC and U.S. policy still struggled with cost allocation and RTO interconnection queues.

Theresa Ghiorzi’s packet notes flag NKT’s 525 kV extruded HVDC cable systems as the commercial product class enabling longer, higher-capacity underground runs with lower losses. Dominion’s February 2026 PJM letter and the PJM Q&A trench specs put Virginia inside that same technology family — aimed at Loudoun, not Iowa rails. Across Virginia, the majority of votes placing data centers into zoning maps and by-right pathways have come primarily from Democrats; that local inventory is why PJM is even weighing a fully underground injection into Northern Virginia. The precedents say burial can be built. PATH’s 2009 spreadsheet says it will not be cheap. Ratepayers and residual landowners will decide whether “minimal impacts” survives contact with an 8-foot trench and 12-acre converter yards.

Email the Board of Supervisors at:
Phyllis J. Randall (Chair, At-Large) – Phyllis.Randall@loudoun.gov,
Michael R. Turner (Vice Chair, Ashburn District) – Mike.Turner@loudoun.gov,
Juli E. Briskman (Algonkian District) – Juli.Briskman@loudoun.gov,
Sylvia R. Glass (Broad Run District) – Sylvia.Glass@loudoun.gov,
Caleb Kershner (Catoctin District) – caleb.kershner@loudoun.gov,
Matthew F. Letourneau (Dulles District) – Matt.Letourneau@loudoun.gov,
Kristen C. Umstattd (Leesburg District) – Kristen.Umstattd@loudoun.gov,
Laura A. TeKrony (Little River District) – Laura.TeKrony@loudoun.gov,
Koran Saines (Sterling District) – Koran.Saines@loudoun.gov

Email the Loudoun County School Board:
April Chandler, april.chandler@lcps.org,
Anne Donohue, anne.donohue@lcps.org,
Deana Griffiths, deana.griffiths@lcps.org,
Ross Svenson, ross.stevenson@lcps.org,
Kari LaBell, kari.labell@lcps.org,
Jon Pepper, jonathon.pepper@lcps.org,
Lauren Shernoff, lauren.shernoff@lcps.org,
Sumera Rashid, sumera.rashid@lcps.org,
Amy Riccardi, amy.riccardi@lcps.org,