The young U.S. offshore wind industry has faced some setbacks since the COVID-19 pandemic disrupted supply chains and sent component costs and interest rates soaring. Several developers have pulled back from existing contracts over the last year and announced plans to rebid with offers that reflect these higher prices.
However, with the first major installation already coming online off the Massachusetts coast and other projects continuing apace, wind turbine manufacturers remain bullish on the technology. The new equipment they’re bringing to market could offer developers options to do more with less, with massive designs intended to meet or exceed generating targets with fewer turbines.
In the months before the pandemic, the offshore wind market was booming, with new projects announced on a near-weekly basis, from the Mid-Atlantic up through New England. The last year, though, has seen several companies pull back and pay big contract cancellation fees, including:
- Park City Wind: an 804-megawatt (MW) project off the Massachusetts coast
- Commonwealth Wind: 1,223 MW, also off the Massachusetts coast
- Revolution Wind 2: 704 MW, off the Rhode Island coast (Revolution Wind 1 is currently under construction)
- Ocean Wind I: 2,248 MW off the New Jersey coast (this project has been canceled)
However, several other major projects are progressing, and one is already beginning to contribute to local power supplies. The first turbine in Massachusetts’ 806-MW Vineyard Wind 1 was installed in October, and the entire $4 billion project is anticipated to come online by mid-2024. Onshore construction has begun for Revolution Wind, a 704-MW installation designed to provide power to Rhode Island and Connecticut, expected to be fully operational in 2025. Farther south, construction on the 2.6-gigawatt (GW) Coastal Virginia Offshore Wind project is expected to begin early next year, with completion by late 2026.
The recent slowdown isn’t unique to the United States, with the United Kingdom’s 1.4-GW Boreas project canceled in July. A September auction for new offshore leases failed to draw a single bid.
The promise of taller turbines
Nevertheless, manufacturers see opportunity in producing larger wind turbines. While these towering machines might cost more individually, they may enable developers to meet targets with smaller installations.
The Vineyard Wind project offers an example of the promise taller turbines offer. Early plans called for 84 turbines rated at 9.5 MW each. However, in 2021, developer Avangrid announced it had shifted the specification to GE’s Haliade-X turbines, with a capacity of 13 MW each. This change cut the number of turbines required to hit the project’s 800-MW target to 62. This will mean considerable installation savings on everything from seafloor foundations to cabling, along with a faster time to market—important advantages given the economic challenges offshore companies now face.
Designers of Dominion Energy’s Coastal Virginia Offshore Wind project have gone even bigger, opting for 14.7-MW turbines from Siemens Gamesa. According to the company’s website, the rotor blades for these turbines are each 492 feet long, for a rotor diameter of 774 feet. These dimensions create a “swept area,” or the area defined by the rotor diameter, of more than 468,000 square feet.
Growing the swept area is critical for increasing turbine electricity output, because longer blades can capture more energy from passing winds. So, manufacturers are pushing size boundaries ever further. Chinese company Mingyang Smart Energy is designing a 22-MW turbine, planned for production in 2025, with a rotor diameter of some 1,017 feet and a swept area of at least 812,425 square feet. To ensure clearance, from water surface to blade tip, it will be taller than New York City’s Chrysler Building.
The bigger units might help developers reach their production goals with fewer turbines, but they also could pose installation challenges—especially with transporting components to installation sites. Specialized ships are required, and there’s currently a global shortage. The first U.S. flagged installation ship is now under construction in Texas. It’s designed to carry 12-MW turbines, with some flexibility for larger equipment. However, it could prove quickly obsolete if 20-MW turbines become a new standard.
The U.S. Department of Energy sponsored research in 2017 to help understand if there’s an upper limit to offshore turbine size. Engineers studied what would be needed to build and operate a 50-MW turbine and found that such designs could be feasible, with a few innovations needed. Among these—creating segmented turbine blades that flip backward in high winds to allow them to survive passing hurricanes.
stock.adobe.com / AIGen