This report by the National Renewable Energy Laboratory (NREL) was funded by the U.S. Department of Energy to evaluate potential overlap between U.S. marine renewable energy resources and existing footprints and spatial needs of the U.S. submarine telecommunications cable industry. Submarine cables are vital to the telecommunications industry, and marine renewable energy—including offshore wind, tidal, and wave energy—has the potential to diversify the U.S. renewable energy portfolio, create jobs, and power the emerging blue economy. Marine renewable energy can complement other renewables by offering consistent, reliable energy in high demand times (e.g., during morning and evening hours), and by siting in proximity to coastal areas with high population density. The first U.S. commercial marine renewable energy facility—the Block Island Wind Farm (Rhode Island)—went into production in December 2016. As implementation and other costs for these technologies continue to drop and increasingly ambitious targets for renewable energy are adopted, marine renewable energy planning and development will need to effectively evaluate the presence of co-occurring ocean uses and resources, like submarine cables.
Repair and maintenance of submarine cables require safe access to cables unfettered by structural obstacles, including infrastructure associated with marine renewable energy development. The submarine cable industry handles 95% of intercontinental internet, data, and voice traffic (Communications Security, Reliability and Interoperability Council IV 2014), thus is vital to the U.S. and global economy. Traditional methods of cable repair require a significant amount of space on the ocean surface, which has motivated the cable industry to recommend “setback” distances (horizontal buffers to either side of cable paths) that define the potential spatial extent of cable repair operations. These cable setbacks hold no legal or regulatory authority, but instead are generally used as best practices or guidelines defining the area over which the cable operator (and more generally the cable industry) has an active stake and potential operational interests.
This work uses publicly available data sets to identify nearly 100,000 kilometers (km) of submarine cable currently installed within the U.S. exclusive economic zone (EEZ). The Code of Federal Regulations (CFR 585.301) specifies that the legal right of way for submarine cables is 100 feet (ft) (~30 meters [m]) to either side of the cable (i.e., 200 ft wide). This narrow corridor has a very small total footprint; currently occupying approximately 0.05% of the total U.S. EEZ area (Table ES-1). Because this area occupies such a small footprint, the authors chose to present the remainder of this analysis using the cable industry’s advised horizontal setback: the maximum of 500 m, or three times the bottom depth (3z setback in Table ES-1). The cable industry advises this setback distance to facilitate cable maintenance and repair.