As you are probably aware, utilities construct, operate and maintain two types of lines to serve customers. Transmission lines haul large amounts of electricity, at very high voltages, from power plants to neighborhood substations. Smaller distribution lines then carry the power to homes and businesses.
Agencies here in Virginia, as well as in other states, have conducted numerous studies on the cost and feasibility of placing distribution and transmission lines underground. The studies have come to the same conclusion: while it is theoretically possible to bury existing distribution lines, such projects would be exorbitantly expensive and disruptive.
Also, the studies have found that, in the vast majority of cases, placing transmission lines underground is not economically viable. Advantages such as improved aesthetics and reliability simply would not outweigh the tremendous additional expense that would burden consumers.
At the request of the General Assembly, the Virginia State Corporation Commission (SCC) in 2005 evaluated placing all distribution lines in the Commonwealth underground. The Commission found that burying all existing overhead lines would cost approximately $80 billion and could take decades to complete. This would increase the bill for the average residential customer by approximately $3,000 per year. In Dominion Virginia Power’s case, this would raise the typical residential consumer’s annual bill by almost 240 percent. The study also found wholesale conversion of overhead facilities to underground placement would cause “significant disruptions” due to construction operations. The full text of the SCC report can be found at this link: http://www.scc.virginia.gov/comm/reports/report_hjr153.pdf
While widespread conversion of overhead facilities appears to be neither practical nor economical, I would like to note that many distribution lines are already placed underground. Developers and utilities routinely install distribution lines underground in newly established subdivisions. Also, some lines have been placed underground in densely developed urban areas such as downtown sections of cities.
Regarding transmission facilities, the Joint Legislative Audit and Review Commission (JLARC) in 2006 reviewed underground placement of high-voltage transmission lines. The JLARC study, done at the Assembly’s request, determined that undergrounding transmission lines would typically cost four to ten times more than overhead construction. For example, placing a 230 kilovolt (kV) line underground would cost $6.42 million per mile, while overhead placement would cost just $1.06 million per mile.
Based on legislation enacted by the Assembly in 2008, the SCC did establish a pilot program for placing a limited number of new transmission lines underground. Three of the four projects authorized under the pilot are already complete or underway, including two in Loudoun County and one in Arlington County. The Commission will evaluate and release its final report on the pilot program by December 2014.
Also, state law already allows localities to set up special tax or assessment districts to provide funding to cover the additional cost for utilities to place new transmission lines underground. These districts are subject to several conditions, including approval by the SCC, an agreement with the utility, and consent of at least 60 percent of the property owners within the proposed district. So far, no localities have created such districts.
A few localities, none in Northern Virginia, also have the right to impose taxes or fees on owners of adjacent property owners to pay for existing overhead distribution lines to underground facilities.
Service reliability, including the possibility of burying utility lines, has been a topic of great interest to both regulators and legislators in recent years. However, at this point, there appears to be no realistic or economical option for widespread conversion of existing overhead facilities, in Northern Virginia or anywhere else in the Commonwealth.