It's an exciting time in wind energy. We've seen some fascinating new wind technology ideas and countries have been setting new records for wind energy generation. If the new design for a giant offshore wind turbine is any indication, it's only going to get more exciting.
A large team of researchers from the University of Virginia, Sandia National Laboratories, University of Illinois, the University of Colorado, the Colorado School of Mines, and the National Renewable Energy Laboratory are working together to build a low-cost 50-MW wind turbine for use offshore. For reference, most wind turbines in use today are 1 to 2 MW and the largest on the market is 8 MW.
In order to have that much energy capacity in a single turbine, it will have to have blades more than 650 feet long, which is longer than the length of two football fields and also two and a half times longer than any existing turbine blade (pictured above is a cross section of a smaller version of the blade the team is working on).
Just building a bigger blade won't work though; it will require a unique design.
“Conventional upwind blades are expensive to manufacture, deploy, and maintain beyond 10-15 MW. They must be stiff to avoid fatigue and eliminate the risk of tower strikes in strong gusts. Those stiff blades are heavy, and their mass, which is directly related to cost, becomes even more problematic at the extreme scale due to gravity loads and other changes,” said Todd Griffith, lead blade designer on the project and technical lead for Sandia’s Offshore Wind Energy Program.
The team is instead focusing on a new design that mimics the way palm trees respond to extra strong wind. The Segmented Ultralight Morphing Rotor (SUMR) turbine responds to wind strength by changing the direction the lightweight blades are facing. In very high winds, the blades bend and align with the wind direction, much like a palm tree in a hurricane, which reduces the risk of damage. When the wind is blowing at lower speeds, the blades spread out to maximize energy generation.
The new blades would be manufactured in segments, which would make them easier to build and transport and also save money.
These segmented blades are ideal for where they will be located -- offshore in high winds. The areas of the U.S. well-suited for offshore wind energy generation are also areas where hurricanes and strong storms occur. These bendable, exascale wind turbines are built to withstand the stress with a hinge at the turbine hub that allows the blades to align themselves with the wind direction when necessary.
Giant offshore wind turbines will help the U.S. to meet the DOE’s goal of getting 20 percent of the nation’s energy from wind by 2030.