UD study: Taming wind just takes a 'backbone'

Apr 6, 2010 - Aaron Nathans - The News Journal

Linking offshore farms could eliminate need for backup power

But a team of University of Delaware researchers say they've quantified a way to make that less of a problem -- and reduce the need to develop costly backup power plants on land or dip into the expensive peak-period electricity market when winds are limp.

Power from planned wind farms off Rehoboth Beach and the rest of the East Coast would be more reliable if they were connected by underwater transmission lines, UD researchers said in a study published Monday in the prestigious journal Proceedings of the National Academy of Sciences.

Linking the farms would reduce fluctuations in power when the wind fails in one area, and that could avoid the need for onshore backups or costly purchases of peak-period electricity, said Willet Kempton, a professor at the university's College of Earth, Ocean and the Environment.

The study is noteworthy because eliminating the problem of fluctuations -- and backups -- could help move projects toward fruition.

But the benefits that the UD study shows could result from linking farms with an underwater transmission line depend on bringing numerous offshore wind proposals online, said Kempton, the study's lead author.

"The scope we're talking about is much bigger than anyone's thinking about right now," he said.

The United States, the largest wind-power producer in the world, has no offshore farms. NRG/Bluewater Wind's plans for a farm 11 miles off the southern Delaware coast is one of six Atlantic Coast projects being planned independently to meet power demand in adjacent states.

Each would route power to the existing land distribution grid, with some provision made to replace the farm-generated current during slow-wind periods. Electricity from interconnected farms would be easier to manage and more valuable than from wind at a single location, according to the study.

In November, 10 eastern governors sent federal officials a letter urging the creation of a "backbone" power line that would connect the wind farms to one another, running parallel to the coast. That would make it easier to spread wind power from spots where the wind is blowing hard to states that need more electricity at any given moment.

The UD study takes this concept a step further, suggesting that the backbone could allow electric utilities to more predictably plan for a stream of wind power coming from offshore.

The study used wind data from 11 meteorological stations spread over 1,553 miles along the East Coast to examine the theoretical effect on wind farms. They estimated the electrical output that would be generated if there were a wind farm on each meteorological site.

Each station showed variability in wind speed, but when averaged together, showed changes of no more than 10 percent in any hour and power from a theoretical offshore transmission grid never dropped to zero. Fossil-fuel generators have a 5.6 percent planned outage rate.

What Kempton calls "the smoothing effect" from linked farms "would reduce one of the barriers to large-scale implementation of wind power," said Mark Jacobson, professor of civil and environmental engineering at Stanford University.

Although the linking notion relies on the widespread success of offshore wind power, "eventually, the farms will come. I don't see it as much of a risk," Jacobson said.

The variability of wind was a big point of discussion during the initial debate in 2007 over whether to place the Bluewater Wind project off the coast of Rehoboth Beach. Delmarva Power officials, initially critical of the proposal, argued the wind doesn't blow much on the hottest peak days.

That would require customers to pick up the added costs of firing up peak-period plants, they argued. The state Public Service Commission still is considering whether a natural-gas plant would need to be built in southern Delaware to back up the wind farm.

Leveling wind power would be "far more" economical, 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 of the farms.

"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.

In Europe, a similar project, called a "super grid" is under discussion to link existing wind farms there.

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.

The U.S. had 35,159 megawatts of wind-power capacity last year, 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.

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.

Today, Atlantic Coast developers are also planning three projects off New Jersey and one in Delaware, and serious discussions are under way to build a project off Rhode Island. Another is in the early planning stages for an offshore site near New York City.

In December, Gov. Jack Markell talked up the underwater power line in his address to the American Wind Energy Association in Boston. Since then, members of his administration have spoken with federal officials and power grid managers PJM Interconnection about testing the cost-effectiveness of the approach.

"The University's research demonstrates the need for these important conversations to continue as we work to maximize the economic development benefits from offshore wind development," said Collin O'Mara, Delaware natural resources secretary.

Kempton's co-authors were Felipe Pimenta, Dana Veron and Brian Colle.

Material from Bloomberg News was used in this story. Contact Aaron Nathans at 324-2786 or anathans@delawareonline.com.