Submarine Cables

Ocean planning helps Martha's Vineyard stay on the grid

The Challenge:

In our increasingly connected world, we expect electricity and high speed internet to be readily accessible. If you live on an island, however, there are limited ways to connect to a grid. Only four electricity and two internet cables connect Martha’s Vineyard, Massachusetts, to the mainland. When one of the electric cables was damaged in 2011 and another in 2012, the island had to rely on generators to meet the demands of a population that swells from 16,000 residents to over 100,000 during the summer. It was time to install a new hybrid submarine cable that would include both electrical conductors to deliver power and fiber optic cables to provide internet access. The challenge lay in identifying the best place to do the job. The last one had been installed in 1990 and since then, awareness about environmental impacts, intersections with other ocean uses, and permitting requirements have increased dramatically.

 

The Process:

In 2009, the State of Massachusetts completed an ocean plan that seeks to balance the needs of all ocean users. It defined a standard for avoiding special, sensitive, or unique marine life or habitats when considering projects. The plan also included detailed maps of the seafloor between the mainland and the island, showing areas of rocky bottom as well as eelgrass beds, both of which are important marine wildlife habitats. The plan promotes co-location of linear infrastructure like cables into corridors, encouraging electrical and fiber optics companies to work together. In 2012, a proposal was submitted for a 4.6 mile new submarine cable to the island.

 

The Results:

According to a study by Seaplan, the management guidelines in the plan improved the regulatory efficiency of state agencies that led to the project review period being cut in half. The installation of the cable started in November 2013 and was completed just six months later. The reliability of electrical and cable service to Martha’s Vineyard improved and ocean planning has proven to be of value to a multitude of people including developers, citizens, conservation groups, and resource managers at all levels of government.

 

Relying on the ocean plan also succeeded in minimizing interference with recreational boating—an important part of the Massachusetts economy—and reducing impacts on seabirds. Disturbing eelgrass beds in shallow waters along the mainland and the island was averted through an innovative tunneling technique. The remaining cable was laid using a trenching and burial process approximately 6 feet down through sandy bottom along a zigzagged route to circumvent the rocky areas.

 

As our need for high speed communication and technologies like offshore renewable energy accelerates, cables will continue to be laid offshore. The Northeast Ocean Data Portal now has a map of potential proposed and alternative areas for a new proposed submarine cable. It is investing in the idea that if proposed and alternative routes can be visualized and discussed with industry and ocean users upfront, the ocean can work better for everyone.


Photography by US Navy (background)

Map provided by Epsilon Associates Inc.