Long wind turbine blades require new composite materials

As Denmark is getting yet greener and focus on wind energy is increasing, challenges are appearing, too. The reason is the possibility of not being able to reach the Danish goals of wind energy to account for half of the Danish electricity consumption, if wind energy is not to going be developed any further. If we wish to supply the customers with cheaper wind turbine power, we are going to build larger wind turbines with longer wind turbine blades than seen so far.

“If building a wind turbine blade from the materials which have been using until now the weight of the blade is going to be increased fivefold when doubling the length”, Professor at DTU Wind Energy Bent F. Sørensen explains.

New composite materials

With the project DACOMAT (Damage Controlled Composite Materials) DTU Wind Energy, in cooperation with among others Norwegian SINTEF and LM Wind Power, look into the possibility of making a wind turbine blade of 107 meters more tolerant to breaks and manufacturing defects. With this very size, two problems appear:

“Firstly, the weight is a large problem. Secondly, keeping tolerances and avoiding small manufacturing defects such as pockets of air in the composite material and glue seams is going to be challenging”, Bent F. Sørensen explains and continues: “With DACOMAT we are looking into the possibility of making the wind turbine blades more resistant to splits and damages. When going towards larger and larger blades, making them perfect is getting yet more difficult. Instead of spending a lot of capacities on localizing defects our philosophy is creating composite materials which are more tolerant to damages in order to prevent prevalence of damages and growth of splits.”

The project group consists of universities as well as manufacturers of composite materials (fiberglass, carbon composite and matrix materials), end users and a certification company.