ORLANDO — Wind energy already accounts for about 5 percent of U.S. electricity generation, which crowned the nation as the global leader in wind production late last year. There is now more than 65 gigawatts (GW) of capacity in 39 states, but according to a new report from the U.S. Department of Energy (DOE), wind should easily have the potential to be installed in all 50 states. How can the industry accomplish this? Easy. Just follow Germany’s lead and install turbines with taller hub heights.
The U.S. currently installs turbines with an average hub height of 80 meters, but if it increases those heights to 110 meters, which is commonly found in Germany and other European countries, the potential output from wind turbines increases by 54 percent. Even more exciting, if the U.S. uses 140-meter turbines, potential increases by 67 percent. This may lead to entirely new markets in areas where wind was previously mostly ignored, like the Southeast.
Light blue coloring identifies land area that meets the capacity factor threshold today but sees an increase in the proportion of the area able to achieve this threshold as a result of turbine and hub height improvements. Orange coloring identifies new land area able to achieve the minimum 30 percent net capacity factor level as a result of turbine and hub height improvements. Credit: DOE 2015.
The report inspired wide discussion during a panel session at Windpower 2015. Jose Zayas, director at the U.S. Department of Energy’s Wind and Water Power Program, said that higher hub heights allow developers to see the industry in completely new ways. “Higher heights equate to better, more behaved wind, which gave us confidence to look at 110- to 140-meter hub heights,” said Zayas. “It is conceivable to see wind in every state of the union.”
These new opportunities could make wind economical in areas where it was not four or five years ago, said Paul Gaynor, executive vice president of North America Utility and Global Wind at SunEdison, which bought First Wind late last year and has been scooping up megawatts of projects since. “This is a great opportunity to think about the country a little differently. It opens up great areas with existing transmission, and if you can exploit these areas it might make wind farms economic all of a sudden.”
Installing turbines at these heights may even open doors for cost reduction, according to GE Power & Water’s CEO Anne McEntee. While wind turbine costs have come down nearly 60 percent in the last few years, there is still a lot of research and development to further reduce costs. Just last year, GE introduced its Space-frame tower that uses 50 percent less steel than traditional towers of the same height, and can also be shipped in standard shipping containers, rather than the oft-difficult methods used for traditional turbines. The tower can also reach 139 meters, which could be ideal for these new prospects. “Advancements like this are continuing to drive costs down,” said McEntee.
Karen Conover, vice president of DNV GL agreed, stating that larger hub heights can lead to even more advancements in other areas. “[Taller turbines] enable technology improvements in other areas like rotors — there are lots of improvements we can make,” said Conover. “We need to shift focus from increased capacity turbines to efficiency, to whole plant design and performance, to interacting with the grid.”
Lead image: Wind turbine. Credit: Shutterstock.