New Jersey’s new project will consist of five 5-megawatt wind turbine about three miles out from Atlantic City. Atlantic City itself was an early wind adopter in the state and it already has wind turbines on the grounds of its wastewater treatment plant, which have attracted the interest of tourists.
The turbines will be installed by Fishermen’s Energy using a new “twisted jacket” foundation designed with ease of manufacturing in mind, thereby lowering costs. The Energy Department describes it as a trussed structure, kind of like a radio tower, consisting of three legs that twist around a central column.
Aside from providing a live demo of the new foundation, the turbines will serve as a research lab for studying the interaction of offshore wind turbines.
The new Oregon project will use a new type of semi-submersible foundation called WindFloat, developed by the company Principle Power. Principle is tasked with installing five 6-megawatt direct-drive wind turbines in water more than 1,000 feet deep, about 18 miles out from Coos Bay.
As with the twisted jacket foundation, WindFloat was designed with simplicity of installation in mind, without the need for highly specialized ships. The entire thing can be assembled on shore and towed out to sea.
As for the foundation itself, the basic concept is like a ship, which sits partly under water and partly above water. The challenge is to anchor it in one place, in deep water. Principle’s solution is a triangular, three-column foundation moored to the sea floor with a system of lines and anchors. The turbine is located on one of the three columns and the other two act as ballast for stability.
According to the Energy Department, more than 60% of US offshore wind resources are in deep waters beyond the reach of conventional fixed-bottom foundations. That includes virtually all of the West Coast, so the success of the Coos Bay project should kickstart private sector interest in the deepwater wind power.
The Virginia project is focused on a hurricane-resilient turbine design, in order to demonstrate that the East Coast’s storm vulnerability need not interfere with its wind power potential. For this project, the utility Virginia Power (aka Dominion Virginia Power) will install two 6-megawatt turbines about 26 miles out from Virginia Beach, using the twisted jacket foundation.
All three projects are going to use direct-drive turbines. Direct drive is a relatively new technology replacing the standard gearbox configuration. One major advantage of direct drive is to reduce the number of moving parts in the turbine.
The Virginia project will use DD turbines from Alstom, the Oregon project will go for Siemens, and New Jersey will go with a company called XEMC.
As for scale, bigger is better: all of the turbines in the three projects will have blades that almost top the length of a football field.