Larger wind turbines can lead to 50% more deployment — DOE report
Wind hub heights — from the ground to the center of the blades — soaring to 110 meters would lower the overall costs of the renewable energy source because it could capture more power from the same amount of wind with longer turbines and larger rotors compared to current 80-meter technology, the report says.
If the United States pursued hubs as high as 140 meters, the nation would have the technical potential to increase suitable areas by 67 percent, DOE said.
The new technology would open more viable sites with “slow wind,” primarily in the Southeast, as well as in states bordering the Ohio River Valley, the Great Lakes Region, the Northeast and portions of the interior Western states and Pacific Northwest.
Capturing the energy in these low-wind-speed areas is necessary for wind to supply 20 percent of U.S. electricity by 2030, DOE said — on a path for it to provide 35 percent of U.S. power by 2050 projected in a companion wind report DOE released earlier this year (Greenwire, March 12).
The technology report — focused on the next 15 years — notes that the United States actually lags behind Europe in hub heights. More than 45 percent of wind turbines recently installed in Europe were 121 to 150 meters tall, boosted by relatively poor wind resource quality at lower above-ground-level heights, higher population density in wind resource areas and price competition with other energy resources.
Most U.S. turbines installed in 2013 had hub heights lower than 100 meters and towers no taller than 120 meters, according to the report.
The report also examines current barriers to higher, larger wind turbines, including transportation, manufacturing and wildlife impact. Although more difficult, boosting heights to 110 meters is not expected “to trigger key transport or logistics threshold constraints,” DOE said.
Still, transporting these large blades on rural roads and under bridges could increase project capital costs by 10 percent, the report says, although the greater energy capacity could overcome these costs over the long term. Crane availability to lift more than 600 tons is also in short supply, DOE said. The agency is supporting research on finding lighter-weight materials such as cloth for blades and lattice structures for towers, as well as processes to manufacture or build components on-site that are cheaper alternatives, the report says.
DOE is also researching technology that could make the wind turbines more friendly to the birds, bats and people who live around the blades. The report acknowledges that the larger blades could have more of an impact on migrating birds at the higher heights and particularly on bald eagles in the Southeast — compared to the golden eagles that researchers are currently focused on in the West and Midwest.
The agency also announced last month almost $2 million to support the development and demonstration of bat deterrent technologies around wind facilities.