In February, we reported that the coast of Maine would be the first test site for floating wind turbines in the US.
The first of those floating turbines is now installed, resting on a platform made out of composite concrete.
"The Castine offshore wind project represents a critical investment to ensure America leads in this fast-growing global industry, helping to bring tremendous untapped energy resources to market and create new jobs across the country,"
says Jose Zayas, director of the Department of Energy’s Wind and Water Power Technologies Office.
In Maine, as with many coastal areas in the US and the world, wind energy is strongest in deeper water where conventional turbine technology isn’t practical. Floating offshore wind turbines can be installed in water up to 2,300 feet deep.
Designed by the Advanced Structures and Composites Center at the University of Maine, the VolturnUS prototype is 65-feet-tall – 1/8th scale of a commercial turbine. Data will be collected to validate and improve the design, and identify technical barriers to reducing the cost of offshore wind.
Creating the design and testing it in a swimming pool:
Built by engineering students, the design uses materials that cut the cost of the system while maintaining high performance and efficiency. For example, the wind turbine sits on a semi-submersible platform made from a lower cost concrete foundation and has a lighter weight composite tower.
An electric cable connects the tower to a small outbuilding on land, where it links to Central Maine Power’s network.
The beauty of this turbine is that it can be built on land and simply towed into place and anchored. Gone are the huge barges, the pile-driving ships and the complexities of construction in the ocean – the reason off-shore wind is so expensive in Europe.
"The most common design method is the mono-pile design," Habib Dagher, the professor who designed the floating turbine, told Bangor Daily News. "A barge comes over and pounds a 15-20 foot diameter steel pile into the sea bed. These piles can be 120 feet long. Think about transporting something this big 10 miles off shore. Then you have to lift the tower in sections, 300 feet high above the ocean, then you have to lift the turbines. The cranes you would need, the vessels you would need, are very expensive."
On the other hand, this much less expensive process of making and placing floating turbines should bring the cost down to 10 cents per kilowatt hour in he next couple of decades, says Dagher.
Offshore wind has yet to get going in the US, as much as we’ve been hearing about test sites and leases. There’s over 4,000 gigawatts of energy potential – four times the amount we have on land right now. It also has the potential to support about 200,000 jobs across the wind supply chain and $70 billion in economic value by 2030 … if it would ever get off the ground.
Read our article on the trend toward floating wind turbines.