Wind Energy FAQs: Offshore

U.S. Electricity from Offshore Wind

There is only one offshore wind farm currently in operation and it is located a few miles off Rhode Island’s Block Island and about the same distance off the eastern end of New York’s Long Island: the Block Island project consists of five wind turbines with a total capacity of 30 megawatts (MW). It was commissioned in December 2016 and, in its first year of operations, has generated approximately 130 gigawatt hours of electricity or about 3/100ths of one percent of the US total.

Block Island is plainly visible also, in the top left, the northern end of Long Island.
Image via ArsTechnica ‘First offshore wind farm in US waters delivers power to Block Island

Although Block Island’s contribution is small, more is coming! The Department of Energy, and multiple states, have ambitious expansion plans. At the present time, due mainly to high regional electricity prices and broad, shallow, seafloors; most offshore wind activity is concentrated in the Atlantic off the Carolinas in the South to Maine in the North. In this region there is already a pipeline of 29 gigawatts (GW) of projects which have been awarded in 16 leases to eight different developers across nine states. These projects – which are shown in the following graphic from the Bureau of Ocean Energy Management (BOEM) – will be built between 2019 and 2035 and, once operational, will be generating almost 20% of the East Coast’s electricity.

This is, however, only the beginning.

The Department of Energy’s ‘Wind Vision’ report demonstrates that, by 2050, wind turbines could be generating 35% of U.S. electricity of which 86 GW of offshore wind could be generating 7-8% of total national electricity needs. The states with the highest wind resource are shown in the following graph (from an NREL report ‘2016 Offshore Wind Resource Assessment for the U.S.‘).  Note that the amount shown, the Net Technical Energy Potential (NTEP), eliminates 84% of the gross resource potential. Nonetheless the NTEP still has an energy potential (7,203 terawatt hours or TWh) which is 80% greater than total 2017 U.S. electricity demand (4,100 TWh). The amount of offshore capacity, required to generate 7,203 TWh, would be 2,058 gigawatts (GW). By comparison, the amount required to meet the 2050 ‘Wind Vision’ target (86 GW) is only 4.1% of this amount.

The state-by-state comparisons indicate an abundance of resource potential in all U.S. regions relative to their electricity consumption. However, the best resource – based on quality and quantity, is found in the the northeast states of Maine, Massachusetts, Rhode Island, New York and New Jersey. Southern states such as Florida, Texas and Louisiana all have large resource areas because of long coastlines and wider continental shelves, but the quality of that resource is lower due to lower wind speeds.