The amount of energy generated by America’s offshore winds last year, exceeded by more than four times the total amount of energy consumed by the nation’s people and industry in the same year. Only a tiny fraction of that wind resource has been harnessed commercially so far. The following map shows average wind speeds off U.S. coasts at a height of 100 meters and extending to the country’s 200 nautical-mile EEZ (Exclusive Economic Zone). The richest wind areas (fastest wind speeds) are off the N. California and New England coasts.
The country’s first offshore wind farm became fully operational December 2016. It lies 3 miles SE of Block Island RI. The electricity it generates is delivered by sub-sea cable, first to a substation on Block Island, then on to the Rhode Island mainland where it connects to the state’s electrical grid. Operated by Deepwater Wind Co., the 30 Megawatt (MW) wind farm consists of 5 wind turbines, each rated at 6 MW. Together, they generate annually about 125 Gigawatt-hours (GWh) of clean energy, enough to serve about 17,000 households. Ørsted, the Danish wind company, acquired Deepwater in 2018 for a reported $510 million.
Offshore wind farms are set to become common features along the NE coast in the coming decade. The Rhode Island wind farm is the pioneer. To see it, take a day trip to Block Island. If you’re driving between NYC and Boston, exit the I-95 at Hwy RI-138 (about 30 miles south of Providence); head east to Kingston. In Kingston turn right at Hwy RI-108 (traffic lights but no sign) and head south to Galilee and the Pt. Judith ferry terminal. Park your car at the ferry terminal (the ferry does carry vehicles). The Ferry departs for New Shoreham, Block Island, four times each day, year round. The trip, port to port, takes 55 minutes (scheduled). Rent a bike in New Shoreham, ride 15 minutes south (or walk the 1.8 miles) to Mohegan Bluffs. The wind farm’s five turbines are located about 3 miles to the SE, clearly visible from the island.
Construction of the first large-scale offshore wind project, an 800 MW, 84 unit farm, will likely begin this year. The project is owned by New Bedford MA based Vineyard Wind Co., a 50-50 partnership Between Copenhagen Infrastructure Partners and Avangrid Renewables. The array of wind turbines will be located about 14 miles south of Martha’s Vineyard MA (see map below). At that distance, the wind turbines will not be visible from land. The project will deliver electricity to Massachusetts for an initial price of 6.5 cents per KW hour, the price to rise by 2.5% year subsequently.
According to the National Renewable Energy Laboratory’s (NREL) 2016 study ‘Offshore Wind Energy Resource Assessment for the United States’, the Gross Resource Potential of the country’s offshore winds (excluding Alaska) is 10,800 GW. Of that amount, 2058 GW is listed as Technical Resource Potential, that is, the amount that could be harnessed today using currently available technology. Areas of the offshore wind zone that are not considered technically available at the present time include: areas where the depth is greater than 1,000 m (3281 ft); areas where the average wind speed is less than 7 m/second; shipping lanes; marine protected areas.
The existing electricity generating capacity of the U.S. is 1072 GW (2017). Of that, about 64% or 646 GW is generated by fossil fuel plants. The electricity from those polluting plants could be replaced three times over by clean electricity generated from Technical Resource offshore wind. The Trump administration is promoting offshore oil/gas exploration. What is the justification for spending billions hunting for fossil energy offshore while clean, cheaper, renewable energy blows past the rigs needed to do the drilling? There isn’t one. As electric cars displace fossil powered cars in the coming years, more clean electricity will be needed, not more petroleum.
1 Kilowatt (KW) = 1,000 Watts
1 Megawatt (MW) = 1,000 KW = 1,000,000 Watts
1 Gigawatt (GW) = 1,000 MW = 1,000,000,000 Watts