Across the past two decades, wind power has become one of the key pillars of the energy transition, accounting for 33% of the global renewables market capacity share in 2024, according to GlobalData. The wind energy sector has experienced significant expansion, with global installed capacity increasing from 438.2 GW in 2015 to 1,150.36 GW in 2026 – a compound annual growth rate of 11%. And looking ahead, GlobalData forecasts suggest that global installed wind power capacity could reach 3,197 GW by 2035.
In recent years, several factors have contributed to pricing pressures in the wind market. Raw material costs and overall project expenses have increased, while fierce competition between manufacturers has forced companies to lower prices in order to win contracts. Shifting government targets, evolving incentive schemes, and lower prices for competing energy sources, including other renewables, can affect demand for wind projects, causing manufacturers to cut prices to remain competitive.
With margins tighter than ever, manufacturers are under pressure to boost their efficiency through quicker, less labour-intensive processes, enabling faster production without compromising on the quality and consistency of the parts produced. A significant opportunity lies in optimising the composite moulding process through reusable technologies – but is the industry ready to adopt a new way of working?
The problem with today’s processes
Large wind turbine components such as nacelles and blades are typically manufactured through infusion moulding to produce lightweight, high-performance parts. The process begins by applying a gel coating over a rigid mould and filling it with dry fibers and other core materials. The mould is carefully covered with a plastic bag or sheet, which is then sealed against the flange and connected to a vacuum pump. The vacuum draws air out of the mould, creating negative pressure which is then used to infuse a resin (epoxy, polyester, or vinylester) through the fibers. At the end of the process, the resin is cured, the vacuum bag is discarded, and the part is removed from the mold for finishing touches.
While this technique is well established in the wind turbine industry, it has introduced several inefficiencies into the process, as well as large volumes of single-use plastic waste. Achieving a quality finish requires careful positioning of the plastic and other components – a time-consuming, manual process that must be repeated for each individual part. If the bag is not laid flatly and evenly, defects can occur on the surface such as sharp fins of cured resin. These must then be removed after infusion, adding another step to the process and raising the possibility for inconsistencies.
A smarter approach
The introduction of reusable silicone solutions has brought much-needed improvements to the infusion moulding process. Working in partnership with composite experts at Magnum Venus Products (MVP), Elkem Silicones has developed a unique silicone solution with specific properties, enabling wind turbine manufacturers to create a reusable vacuum bag for easier, quicker moulding with better part consistency.
Elkem’s Bluesil RTV 3724 A&B is first applied on specific parts of the mould and then built up across the whole surface into layers using an MVP spraying machine and a brush. Infusion channels and reinforcement mesh are added, and the silicone bag is left to cure at room temperature for 24 hours before it is demoulded and used time and time again.
“You have to make an investment at the beginning to create the customised silicone bag, but once that’s done you can produce parts very quickly and very easily,” explains Valentin Bacquet, Technical Service Manager, Industrial Assembly and Moulding, Elkem Silicones.
He adds that the bag can be used across upwards of 500 moulding cycles in combination with a polyester resin, saving significant plastic waste from landfill while also reducing the manufacturer’s consumables costs.
Depending on the specific type of resin used, the number of cycles may be in the thousands, and a return on investment can be expected somewhere between 10 and 20 cycles in. When it comes to the silicone itself, specific properties ensure its ease of use and durability.
“It’s a very specific moulding silicone that we developed with a partner,” says Bacquet. “It’s a two-component polyaddition product with a very specific thixotropic behaviour, because it needs to be sprayed onto the mould precisely without flowing and running off.”
Strong chemical and mechanical resistance were essential for ensuring a long lifespan. “The silicone has to have a very strong resistance because of the resins. It also has good mechanical strength, because it has to be manipulated by hand and adjusted. Finally, it needs to be demoldable, with very good release properties.”
Reusable silicone bags represent a major advancement in vacuum infusion moulding, enhancing efficiency, reducing labour costs, and minimising waste. Elkem and MVP are reshaping the composite moulding landscape, providing a much-needed solution to help wind turbine manufacturers ensure profitable production in a highly competitive market.
To learn more about the role of silicone solutions in the energy transition, please download the whitepaper below.
