Taking blade manufacture to the next level

Wind turbine manufacturers are showing increasing interest in exploiting the potential for improved quality and lower costs that pultruded composites promise. Exel Composites, with cost effective, global production capabilities and market-leading carbon pultrusion expertise, is perfectly positioned to meet this demand.

Exel's Wind Energy team and European, Chinese and new US production facilities are collaborating closely with wind energy customers as they seek to introduce pultrusion into their next-generation designs.


Better, faster

The wind energy industry is extremely dynamic. Every turbine producer has their own design philosophy and they tailor their blades taking into account not only aerodynamics, but also a complex combination of factors including wind speeds, turbine dimensions, blade frequencies and tower set-up. And whilst cost out remains the top priority, a number of other key trends are driving innovations in blade manufacture today.

The biggest of these is industrialization. Although the wind industry is relatively young – the first tower was erected around 30 years ago – it has grown rapidly into a global market of more than 50 GW. However, many companies have not yet fully industrialized their blade manufacturing process so this is still to some extent a manual process.

Blade manufacturers are also always striving for improved quality, which translates into multiple design, production and service benefits.

A third priority is faster cycle time. A blade mould requires a very high investment and blade models change frequently, so it is crucial to lower cycle times as far as possible. By reducing the cycle time and increasing output, fewer moulds and less production space are needed, and additionally the cost of the blades manufactured from each mould is reduced.

Today, a cycle time of about 12-24 hours is possible, depending on the material chosen for the blade, and the blade producers are pushing for further reductions.

Pultrusion can support all three objectives of industrialization, improved quality, and reduction of cycle time.

Driving down costs

The blade spar cap, a critical structural component, is one target application for pultrusion. While infusion is still the dominant technology in spar production at present, pultruded glass and carbon fiber spar caps, supplied on coils and ready to install, can deliver significant reductions in cycle time and costs.

Pultrusion, a continuous process, also results in parts of consistently high quality. In addition, the costs per part are stable since the exact amount of fibre and resin at each location in the part is known and does not vary from part to part, which is not as easy to achieve with infusion. This makes it possible to design parts of lighter weight which are also much stronger than those manufactured with other techniques. This weight reduction leads to cost savings throughout the turbine.

For example, every blade must weigh the same on the tower and to achieve this counter or balance weights are used. If these balance weights can be removed or reduced by using pultruded parts, the tower, generator and drive train can all be designed to be less substantial. So although pultruded parts may be more expensive than infused, overall system costs are driven down.

One leading turbine producer has already introduced pultruded carbon fiber spar caps with great success, and the others are looking to follow suit. Exel Composites is currently involved in programmes with all the leading global players, together with our recent US acquisition Diversified Structural Composites (DSC), which has been actively developing carbon spar caps for more than 10 years.

And while spar caps offer the biggest potential for pultruded composites in volume terms, there are numerous other opportunities for pultrusion in the blade, turbine and tower. Exel offers solutions for parts such as blade root joints, generator insulation components, platforms, walkways, handrails and ladders, and cable management systems. Glass fibre composites are already specified in the US market because of strict restrictions relating to electrical conductivity.

Global development partner

For the biggest players in the highly-competitive wind energy industry, global availability of products, consistent quality and competitive pricing are paramount requirements for suppliers. The acquisition of DSC makes Exel Composites the only pultrusion company with significant production presence on all three major continents, and truly able to serve global wind energy companies locally. Our production technologies also ensure the high speed pultrusion of high quality parts and the most efficient use of material, helping to make carbon fiber profiles more cost effective than ever before.

Offering an unparalleled combination of composite materials and process expertise, Exel is the ideal development partner to support wind turbine design and technology teams as they move to adopt pultrusion in their new blade concepts. As the wind energy industry prepares to take this next step, we will ensure that our partners stay ahead of the competition and achieve long-term success in the market.

Further informatio
Mr. Kari Loukola
Senior Vice President
Sales & Marketing
Exel Composites
tel. +358 40 5040 755
kari.loukola@exelcomposites.com