Buried Transmissions Lines in Transportation ROWs Could

by Rowleys Electrical

Buried high-voltage direct current (HVDC) lines in the rights-of-way along highways, waterways and railroad tracks have the potential for carrying more renewable energy cross-country more reliably than overhead power lines. There are challenges, but there are also incentives to make it worthwhile.

To encourage the development of “Clean Energy and Connectivity” projects along highways to expand and modernize the grid, the U.S. Department of Transportation (USDOT) provided guidance about using existing ROWs for new lines. In addition to proposing the creation of a Grid Deployment Authority to leverage existing ROWs, the Biden administration dedicated $100 billion of its American Jobs Plans for new transmission infrastructure. The U.S. Department of Energy announced financial tools for building high-voltage electric transmission lines, and the USDOT indicated prioritization of projects that use these funds.

Buried HVDC transmission has a 40-year lifespan and requires a 5-foot ROW. Each section is connected about every ½ mile inside a joint vault. Converter stations are aboveground outside the ROW.

Buried HVDC lines reduce carbon emissions without disturbing the landscape like overhead power lines do. Installation costs are commensurate. Besides requiring less space, benefits over current AC systems include energy networks that are more stable, efficient and environmentally friendly. HVDC also experiences lower losses over long distances, even when conveying large amounts of electricity.

Several projects to install buried HVDC transmission technology within existing transportation ROWs are underway, including the SOO Green HVDC Link along railway corridors in Iowa and Illinois. The $2.5 billion SOO Green project will carry wind-generated power from the Midwest to the mid-Atlantic coast. Cost parity with overhead transmission lines and financial backing enable the project to move forward, but several challenges prevent similar projects from advancing, such as:

  • Siting
  • Permitting
  • Cost-sharing disagreements between utilities, state regulators and grid operators
  • Legal challenges from state legislatures, county agencies, private landowners and state regulators
  • Disconnect between federal and state authorities over the interstate highway system

While the SOO Green project follows railroad tracks, HVDC transmission along highways could facilitate charging stations for cars and trucks.            

The existing 45,000 charging stations nationally won’t be sufficient to keep up with expectations that 61% of global new passenger vehicle sales will be zero-emission by 2030 and 100% by 2038, according to a BloombergNEF analysis. Thus, Congress has designated $7.5 billion to build a nationwide network of half a million charging stations.

Maine and New Hampshire passed laws to encourage placing transmission along transportation ROWs, according to a Federal Energy Regulatory Commission report.

Other states such as Minnesota are conducting feasibility studies on integrating existing transportation, communications and electric infrastructure. The Minnesota Department of Transportation (MnDOT) is working with the NextGen Highways Team to study opportunities and barriers related to burying HDVC within highway ROWs. MnDOT is evaluating the environmental impact, the impact on existing infrastructure, accessibility for maintenance and repair work, permitting and costs.

With the rise of electric and autonomous vehicles, electric infrastructure must evolve and expand to support them.