By Liz Burdock, President and CEO, Business Network for Offshore Wind
Visitors who brave the trip from the Rhode Island mainland to the five-turbine wind farm three miles off of the Block Island coast invariably rave about the massive size and the majestic nature of the turbines, especially when they are right underneath these amazing structures. What they don’t know is that the project’s designers made a key decision to tie the wind farm to both the island and the mainland via underwater cable, and that has made all the difference in fully utilizing the wind farm’s clean power for consumers both on Block Island and the larger Rhode Island community.
In the same way, offshore wind farm supporters like to debate the layout of wind farm turbines, including orientation, distance from shore, distance between turbines, etc., but when it comes to project cost, impacts on the ocean floor, connecting to the mainland grid and other critical issues, offshore wind cables play a vital role.
“Cables are a critical component for offshore wind farms, but in the past they have not always received the attention they deserve,” as John Manock, editor of SubCableWorld magazine, has pointed out. Cables connect the turbines to each other, and then an exit cable runs from the wind farm to an offshore power substation and then directly to an onshore substation to be connected into the land-based electrical grid.
These heavyweight cables are heavy and expensive, and it can take two to three years to manufacture them to the specs required by a particular wind farm. They require special offshore wind vessels to dig a trench along a carefully designed route, drop in the cables, and then backfill them with four to six feet of soil or sand to both protect the cable and the ocean bottom wildlife living in the area.
The ocean bottom is a harsh environment, and cable damage accounts for as much as 80% of insurance claims at offshore wind farms. If something does go wrong with a subsea cable, divers often have to plunge more than 100 or 150 feet to the ocean floor to make the repair.
Of course, offshore wind cables are also a major business opportunity as a vital piece of the supply chain, which is why my organization is encouraging the top global cable manufacturers to set up shop in the U.S. to serve this market. As a part of that effort, we are partnering with SubCableWorld to hold the first conference focusing specifically on offshore wind cable supply chain issues in the United States.
The one-day event, entitled “Subsea Cables: A Critical Connection,” will be held on October 10, 2019, at the Houston Aquarium in Houston, Texas. The conference will cover issues related to the development of the US cable supply chain, insurance and risk management, technological advances in cable designs, installation and maintenance and other topics. In addition, SCW will present its demand forecast for the US offshore wind market. Click here for information on this conference. We encourage those who follow offshore wind to go to the SCW site to learn more about subsea cables.