Offshore Wind Farms in U.S. Should Be Linked, Researchers Say

April 05, 2010, 3:16 PM EDT
By Jim Efstanthiou Jr.

April 5 -- Power from planned wind farms off the U.S. East Coast would be more reliable if the projects were connected by transmission lines, researchers at the University of Delaware said in a study.

Linking the farms would reduce fluctuations in power when the wind fails in one area, said Willet Kempton, a professor at the university’s College of Earth, Ocean and the Environment in Newark, Delaware. The study used wind data from 11 meteorological stations spread over 1,553 miles (2,500 kilometers) along the East Coast to examine the theoretical effect on wind farms.

The U.S., the largest windpower producer in the world, has no offshore farms. Six projects off the coastline from Massachusetts to Delaware are being planned independently to meet power demand in adjacent states. Electricity from interconnected farms would be easier to manage and more valuable than from wind at a single location, according to the study.

“If you take our approach, you say wait a minute, we’re not just going to pick the next wind farm based on where there’s a friendly state government,” Kempton said in an interview. “But rather we’re going to look at the next 20 wind farms and figure out how we’re going to get the most power out of them.”

The U.S. had 35,159 megawatts of windpower capacity last year, followed by China and Germany, according to the World Wind Energy Association. About 300 gigawatts will be needed, 54 gigawatts from offshore turbines, to reach an Energy Department target of producing 20 percent of U.S. power from wind by 2030, according to the Washington-based American Wind Energy Association.

Cost Competitive

Wind power accounts for 2 percent of U.S. electricity generation and is ahead of schedule to meet the 2030 target, according to the association, which represents more than 2,500 companies.

Leveling wind power with transmission lines is cost competitive with the traditional methods of using reserve generators and redundant power line routes, and “far more” economical than utility-scale electrical storage, according to the study. Linking all the planned Atlantic Coast offshore projects with 350 miles of undersea cable would add $1.4 billion to the $10.5 billion estimated construction cost.

“This is in line with the market cost of leveling wind via existing generation, currently estimated to add about 10 percent to the cost of energy,” according to the study.

Power Outages

During the five-year study period from 1998 to 2002, power from a theoretical offshore transmission grid never dropped to zero. Fossil fuel generators have a 5.6 percent planned outage rate.

“Each individual wind power generation site exhibits the expected power ups and downs,” according to the study. “But when we simulate a power line connecting them, called here the Atlantic Transmission Grid, the output from the entire set of generators rarely reaches either low or full power, and power changes slowly.”

Two-thirds of the offshore wind power in the Northeast can supply all electricity, light vehicle transportation fuel and building heat for states from Massachusetts to North Carolina, according to the study.

Source: http://www.businessweek.com/news/2010-04-05/offshore-wind-farms-in-u-s-should-be-linked-researchers-say.html

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