Block Island Wind Farm: Historic project enters final stage
Alex Kuffner
akuffner@providencejournal.com
Deepwater Wind is making history this week as it installs the first offshore wind turbine in the United States.
The giant machine is being mounted on a steel platform that rises above the Atlantic Ocean about 3 miles southeast of Block Island. It is going up in stages in a process that started Tuesday morning.
Three tower sections were fitted together first, one atop the other, totaling 270 feet in height. They were followed by the boxy nacelle that houses the generating equipment at the heart of the turbine. It was gently lowered on top of the tower Wednesday morning. Later Wednesday, in the trickiest step of the installation work, crews were set to start attaching the three blades that will soon capture the powerful winds off the ocean.
The six-megawatt turbine made in France by General Electric Renewable Energy is one of five that is going up in the next few weeks as part of the Block Island Wind Farm, the approximately $300-million demonstration project that Deepwater has been working on for eight years.
After returning to the island from an observation boat Wednesday afternoon, Jeffrey Grybowski, CEO of the Providence-based company, said the project is coming together fast.
"For so long we were dealing in months. And now we're dealing in hours. It's amazing to see the same nacelle I was touching in a factory a few months ago sitting on top of the tower," he said as he prepared to head back out to sea to watch the blades go up.
The work this week kicked off a month-long push to complete construction of the 30-megawatt wind farm. A couple months of testing will follow before the turbines go into full operation sometime this fall, sending power first to Block Island and then the mainland electric grid through underwater cables.
Putting up the wind turbines — which will each rise 589 feet above the ocean's surface when the blades reach their highest point — may be the part of the 18-month construction process that captures the imagination, but, in truth, the hardest part of the project is over.
That took place over four and half months last year when Deepwater installed the latticework "jackets" that hold the wind turbines above the ocean's surface. The foundations were custom-built in Louisiana to suit the unique geology off Block Island and each one was a little different because of the varied water depths across the project site. Securing them to the ocean floor with piles driven deep into the bottom was painstaking work, but once the last of the structures was set in place last November, Deepwater had flat, level spots to erect the turbines.
The final round of work involves three main ships: the Brave Tern, a 433-foot-long Norwegian vessel that specializes in putting up offshore wind turbines; and two 137-foot-long support ships, the Caitlyn and the Paul, both owned by Louisiana-based Montco Offshore. All three are jack-up vessels that can extend telescopic legs down to the ocean floor and raise their hulls above the water for stability unmatched by regular floating ships.
The Brave Tern is at the center of the action. Deepwater hired the vessel owned by Oslo-based Fred. Olsen Windcarrier because there is no ship like it in the United States. Not only can it lift an object of up to 800 tons to a maximum height of 335 feet, it can do so with extreme precision because of its jacking ability. That is critical when the ship installs the turbine nacelles, which each weigh 400 tons and are filled with sensitive equipment that a violent jolt could damage.
Since it was built in 2013, the ship has installed 200 turbines off Europe, including a previous version of the GE model that Deepwater is using, said Eskil Roset, a project manager for Fred. Olsen who is coordinating the company's work off Block Island. This type of work is nothing new for the vessel.
"It's what we do," Roset said. "The difference is only the location."
The Brave Tern arrived in Narragansett Bay Sunday morning after a 16-day journey from Saint-Nazaire, France, where it picked up the nacelles. It set anchor off Goat Island so it could be inspected by the Coast Guard and take on additional crew members that flew in from Europe. That same morning, the Caitlyn and the Paul, carrying the turbine towers and blades that had been in storage at the Port of Providence, set sail for the project site off Block Island.
The Brave Tern followed Monday night. Everything went smoothly and it lifted the first tower section onto its foundation by noon on Tuesday.
Deepwater has budgeted three days to put up each turbine, but, says Grybowski, that's based on a conservative schedule. In Europe, where thousands of offshore wind turbines are in operation, the standard is a day and a half.
Fitting the blades in the nacelle is expected to be the most difficult part of the operation because they are long, flexible and unwieldy.
"We're lifting something that's designed to catch the wind," Grybowski said.
Deepwater is planning on completing the work in 25 days. But that time frame includes potential weather delays, so the installation could be quicker if there are no strong winds or high seas.
"The weather is good so far and all the contractors know what they need to do," Grybowski said. "Things are going according to plan."
- akuffner@providencejournal.com