While the US is only on the verge of bringing its first wind farm online, Audrey Leon surveys some of the prospects slated for the country’s federal waters.
LEEDCo’s mono bucket foundation. Photo from DOE.
Unlike Europe, the US has been a bit slower to adopt renewables as part of the energy mix. According to the US Energy Information Administration, in 2015, renewable energy sources accounted for about 10% of total energy consumption and about 13% of electricity generation in the country. Petroleum and natural gas make up approximately 63% of total energy consumption.
In May of this year, the US Department of Energy announced three offshore wind projects that would be eligible to receive up to US$40 million each in additional funding.
DOE chose the Atlantic City Wind Farm, developed by Fishermen’s Energy, offshore New Jersey; Lake Erie Energy Development’s (LEEDCo) Icebreaker project, near Cleveland, Ohio; and the University of Maine’s New England Aqua Ventus I project.
The 24MW Atlantic City Wind Farm will feature six 4MW Siemens turbines, about 3mi offshore Atlantic City, New Jersey, in approximately 12m water depth. The project will utilize a fixed bottom, “twisted jacket” foundation, or Inward Batter Guide Structure, from Keystone Engineering, which DOE says is easier to manufacture and install than traditional foundations.
“During operation, the Fishermen’s project will act as an at-sea laboratory to further our knowledge about offshore wind, investigate the interactions between turbines, test new control systems, and provide information about potential environmental impacts of offshore wind while reducing the levelized cost of energy from offshore wind,” says DOE.
Keystone Engineering’s “twisted jacket” foundation to be used on the Atlantic City Wind Farm.
The Lake Erie project, developed by LEEDCo, will see six 3.45MW direct-drive turbines installed on mono bucket foundations (a design which takes elements of gravity-based structures, monopiles and suction buckets) approximately 7mi off the coast of Cleveland, Ohio, in Lake Erie.
The mono bucket foundation was selected through significant engineering analysis, DOE says, and is expected to reduce installation time, costs, and environmental impacts compared to traditional foundations that require pile driving.
The third project championed by DOE is the University of Maine’s. This involves a pilot floating offshore wind farm with two 6MW direct-drive turbines on semisubmersible foundations at a test site off of Monhegan Island, Maine. DOE says due to the project’s deeper water depths traditional foundations are not practicable. The university will instead develop a new floating platform called VolturnUS.
According to the University of Maine, the VolturnUS design uses a concrete semisubmersible floating hull and a tower made from composite materials designed to reduce both capital, operation and maintenance costs, and to allow local manufacturing.
Denmark takes US interest
The twisted jacket foundation upright. Photos from Keystone Engineering.
In February, Denmark’s DONG Energy said it would take over an offshore New Jersey wind lease previously held by RES Americas Developments. The New Jersey lease encompasses 160,480 acres, approximately 10nm offshore in 80ft of water. DONG said the area could potentially accommodate more than 1000MW of offshore wind.
“The US is an interesting market for offshore wind with the potential to become a significant area for future development,” says Samuel Leupold, executive vice president of wind power, DONG Energy.
The New Jersey lease is the second US lease area for DONG Energy. The first was acquired in June 2015, offshore Massachusetts. That project, Bay State Wind, calls for the construction and operation of a utility scale offshore wind farm off the southern coast of Cape Cod with an installed capacity of up to 1000MW. With water depths between 130-165ft, this site sits approximately 15nm from shore.