Transmission Lines: Issues Associated with High-Voltage Direct-Current Transmission Lines along Transportation Rights of Way

Electricity is central to the national economy and the daily lives of many Americans, powering homes, businesses, and industries. Today, an extensive system consisting of more than 150,000 miles of high-voltage transmission lines works to provide reliable electricity service and transport electricity from power plants to consumers. Federal and state entities share responsibility for regulating the electricity system. On the federal level, the Federal Energy Regulatory Commission (FERC) regulates interstate transmission of electricity and wholesale rates, among other regulatory activities. State public utility commissions are generally responsible for regulating retail electricity sales and, in some cases, planning for new power plants and transmission lines. However, as studies have shown, growth in electricity demand has strained the nation's transmission system, resulting in less flexibility to respond to system problems and an increased risk of potential blackouts. These issues have led some to suggest that new lines or other investments in the transmission system may be required to increase capacity and accommodate growing electricity demand. Several companies have recently introduced proposals to build new high-voltage direct-current (HVDC) transmission lines. Some of these proposed lines would follow active transportation rights of way, such as railroads, highways, and pipelines. Some stakeholders have raised concerns about the potential economic, safety, and security issues related to collocating new HVDC transmission lines along transportation rights of way, particularly for nearby residents and consumers of electric power. Given these issues, Congress included a provision in the Implementing Recommendations of the 9/11 Commission Act of 2007 requiring us to assess the siting of HVDC transmission lines along active railroad and other transportation rights of way and report to appropriate congressional committees. In response to this requirement and after discussions with the committees, we examined (1) the role of the federal government in siting HVDC electric transmission lines along active transportation rights of way, (2) advantages and disadvantages of adding transmission lines and using HVDC technology, and (3) benefits and risks associated with the siting of HVDC electric transmission lines along active transportation rights of way.