How offshore wind can power New York and Boston

There is one thing most people probably don’t know about offshore wind.

Unlike land-based wind, which tends to blow strongest at night and in the early morning hours — when energy demand is low — offshore wind usually peaks during the day, when demand is highest.

Just one more reason, argue Stanford University scientists in a new paper [PDF], to get to work on reaping the vast bounty of power off the East Coast of the United States.

And we do mean vast.

The Stanford team determined that after taking into account typical transmission losses and inefficiencies common to offshore turbine arrays, “the U.S. East Coast offshore winds were found to produce from 965 to 1,372 terawatt hours of electricity annually, enough to satisfy the demands of one-third of the United States, or all of the East Coast, from Florida to Maine,” according to a Stanford release.

The bulk of the East Coast wind resource is found from Virginia north – a good thing, since that portion of the coast is far less likely to face devastating hurricanes. The researchers say that turbines can withstand category 3 hurricanes, and nothing beyond that strength hit the Virginia-to-Maine zone from 1851 to 2006.

So how many turbines would it take to power the East Coast? Oh, just 140,000 5-megawatt turbines, the researchers say.

Considering how daunting it has been to get a single U.S. offshore wind array built – the Cape Wind project has been muddling along for more than a decade, and construction still hasn’t begun – this at first blush sounds stupidly unrealistic.

However, unlike with Cape Wind, under the Stanford scenario most of the turbines would be out of sight. “The analysis assumed the use of only one-third of available shallow water locations out to 30 meters depth of water, and two-thirds of remaining sites out to 200 meters depth,” according to the university.

That actually might be feasible, given the strides being made toward developing floating turbines that could be placed in waters more than 50 meters deep.

Whether this scenario ever comes anywhere near close to panning out, it does highlight the advantages of offshore wind over land-based wind (even if development costs are two or three times as high). In addition to the wind blowing when we need the energy, this resource also happens to be very close to major population centers.

“This study enables the planning and development of very large wind farms offshore of New York City or Boston. Connecting the power to the grid would be technically as easy as laying a cable in the sand and hooking it directly into the grid without the need to build often controversial transmission lines on the land,” said team member Mike Dvorak.

Pete Danko, EarthTechling