By Dag Kirschke, Wind Energy Segment Owner, Exel Composites
The demand for wind energy is increasing. It’s clean, cost effective and sustainable. As environmental and climate change concerns are influencing a greater need for renewable and sustainable energy, wind turbines are a substantial part of the solution — with over 340,000 wind turbines in the world already used to produce energy. For example, China is responsible for over one-third of the world’s wind energy capacity and in 2015 installed more wind turbines than the EU, whereas Scotland generated enough electricity from wind in 2018 to power the equivalent of five million homes. Industry experts believe that if the demand for wind energy continues, one-third of the world’s electricity needs will be fulfilled by wind power by 2050.
Today, manufacturers are facing continued pressure to produce higher returns on turbines, with improved cost efficiency and increased power output that can generate more energy. To achieve this, manufacturers are creating turbines with longer blades that capture more wind, in turn generating more energy. However, a longer blade means increased weight, which works against efficient power production. In order to maintain a powerful and efficient turbine with longer blades, manufacturers require materials that are lightweight and stronger than traditionally used materials.
A composite solution
A large part of a turbine blade’s strength comes from a support beam, or spar cap, which runs the length of the blade. Traditionally, spar caps have been made out of fiberglass, which provides the needed strength and stiffness, with less weight than other materials like metals. Yet, with the push for longer blades, carbon fiber is used as its lighter weight compared to fiberglass, allowing longer blades to capture more wind energy. Typically, each blade manufacturer will determine in its design the point at which carbon becomes the optimal solution, and the spar cap is designed accordingly.
Exel Composites works closely with turbine and blade manufacturers to engineer, manufacture and deliver composite solutions for blades, including fiberglass and carbon fiber spar caps, as well as many other composite solutions used in wind turbines. We use our experience of design, combined with manufacturing technology allows us to help turbine manufacturers produce more efficient turbines by reviewing design specifications and proposing an appropriate solution.
To keep up with the growing demand for wind energy, manufacturers need to invest in long-lasting, high-performance composites, that contribute efficiencies to help ensure the maximum amount of energy is produced. Using a composite manufacturer like Exel means that design specifications will be thoroughly reviewed and met in order to achieve a powerful and efficient turbine.
In bicycle frames, one manufacturer has begun using a small proportion of graphene (under 1%) to enable stiffer stronger and lighter frames. As graphene costs come down to price not too dissimilar to carbon fibre, I guess that incorporating small quantities of graphene into the outer portions of the carbon fibre layup may be a solution to further lengthening the blades whilst keeping weight acceptable.